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In. Boston

ANNUAL'

O F

SCIENTIFIC DISCOVERY:

R,

YEAR-BOOK OF FACTS IN SCIENCE AND ART

FOR 1864.

EXHIBITING THB

MOST IMPORTANT DISCOVERIES AND IMOVEMTS

1 N

MECHANICS, USEFUL ARTS, NATURAL miLOSOrHY. CHEMISTRY,

ASTRONOMY, GEOLOGY, ZOOLOGY, BOTANY, MINERALOGY,

METEOROLOGY, GEOGRAPHY, ANTIQUITIES, ETC.

TOGETHER WITH

NOTES ON THE PROGRESS OF SCIENCE DURING THE YEAR 1863; A LIST

OF RECENT SCIENTIFIC PUBLICATION'S; OBITUARIES OF

EMINENT SCIENTIFIC MEN, ETC.

EDITED BY

DAYID A. WELLS, A.M.,M.D.,

AUTHOR OF PRINCIPLES OF NATURAL PHILOSOPHY, PRINCIPLES OF CHEMISTRY,

FIRST PRINCIPLES OF GEOLOGY, ETC.

BOSTON:

GOULD AND LINCOLN,

59 WASHINGTON STREET.

NEW YORK: SHELDON AND COMPANY.

CINCINNATI: GEORGE S. BLANCIIARD.

LONDON: TRUBNER & CO.

1864.

Entered according to Act of Congress, in the year 1864, by

GOULD AND LINCOLN,
In the Clerk's Office of the District Court for the District of Massachusetts.

NOTES BY THE EDITOK

ON THE

PROGRESS OF SCIENCE FOR THE YEAR 163.

THE thirty-third annual meeting of the British Association for the
Advancement of Science was held at Newcastle-on-Tyne, Sir William
Armstrong (the gun-maker) being in the chair. The meeting was
above the average, as respects the numbers in attendance and the
interest of the papers brought forward. Sir Charles Lyell was se-
lected as the President for 1864.

From the annual address of the President, reviewing the recent prog-
ress of Science, we make the following extracts. Referring to the
district of Newcastle as the birth-place of Stephenson, and of locomo-
tives and railways, he said , " The history of railways shows what
grand results may have their origin in small beginnings. When coal
was first conveyed in this neighborhood from the pit to the shipping-
place on the Tyne, the pack-horse, carrying a burden of three hun-
dred-weight, was the only mode of transport employed. As soon as
roads suitable for wheeled carriages were formed, carts were introduced,
and this first step in mechanical appliance to facilitate transport had
the effect of increasing the load which the horse was enabled to carry,
from three hundred-weight to seventeen hundred-weight. The next
improvement consisted in laying wooden bare or rails for the wheels of
carts to run upon, and this was followed by the substitution of the four-
wheeled wagon for the two-wheeled cart. By this further application
of mechanical principles the original horse-load of three hundred-weight
was augmented to forty-two hundred-weight. These were important
results, and they were not obtained without the shipwreck of the for-
tunes of some men whose ideas were in advance of the times in which
they lived. The next step in the progress of railways was the attach-
ment of slips of iron to the wooden rails. Then came the iron tramway,
consisting of cast-iron bars of an angular section; in this arrangement,

in

IV NOTES BY TIIE EDITOR

the upright flange of the bar acted as a guide to keep the wheel on the
track. The nexr advance was an important one, and consisted in
transferring the guiding-flange from the rail to the wheel ; this improve-
ment enabled east-iron edge-rails to be used. Finally, in 1820, after
the lapse of about 200 years from the first employment of wooden bars,
wrought-iron rails, rolled in long lengths, and of suitable section, were
made, and eventually superseded all other forms of railway. Thus,
the railway system, like all other large inventions, has risen to its pres-
ent importance by a series of steps ; and so gradual has been its prog-
ress that Europe finds itself committed to a gauge fortuitously deter-
mined by the distance between the wheels of the carts for which wooden
rails were originally laid down.

Last of all came the locomotive engine, that crowning achievement
of mechanical science, which enables us to convey a load of 200 tons at
a cost of fuel scarcely exceeding that of the corn and hay which the
original pack-horse consumed in conveying its load of three hundred-
weight an equal distance.

In thus glancing at the history of railways, we may observe how
promptly the inventive faculty of man supplies the device which the
circumstances of the moment require. No sooner is a road formed fit
for wheeled carriages to pass along than the cart takes the place of the
pack-saddle : no sooner is the wooden railway provided than the wagon
is substituted for the cart : and no sooner is an iron railway formed,
capable of carrying heavy loads, than the locomotive engine is found
ready to commence its career. As in the vegetable kingdom fit con-
ditions of soil and climate quickly cause the appearance of suitable
plants, so in the intellectual world fitness of time and circumstance
promptly calls forth appropriate devices. The seeds of invention ex-
ist, as it were, in the air, ready to germinate whenever suitable con-
ditions arise, and no legislative interference is needed to insure their
growth in proper season."

Necessity for a Neiv System of Writing. " The facility now given
to the transmission of intelligence and the interchange of thought is one
of the most remarkable features of the present age. Cheap and rapid
postage to all parts of the world, paper and printing reduced to the
lowest cost, electric telegraphs between nation and nation, town and
town, all contribute to aid that commerce of ideas by which wealth and
knowledge are augmented. But while so much facility is given to
mental communications by new measures and new inventions, the fun-
damental art of expressing thought by written symbols remains as im-
perfect now as it has been for centuries past. It seems strange that

ON THE PROGRESS OF SCIENCE. V

while we actually possess a system of short-hand by which words can
be recorded as rapidly as they can be spoken, we should persist in
writing a slow and laborious long-hand. It is intelligible that grown-up
persons who have acquired the present conventional art of writing
should be reluctant to incur the labor of mastering a better system ;
but there can be no reason why the rising generation should not be in-
structed in a method of writing more in accordance with the activity
of mind which now prevails. Even without going so far as to adopt
for ordinary use a complete system of stenography, which it is not easy
to acquire, we might greatly abridge the time and labor of writing by
the recognition of a few simple signs to express the syllables which are
of most frequent occurrence in our language. Our words are in a
great measure made up of such syllables as com, con, lion, ing, able-,
ain, ent, est, ance, etc. These we are now obliged to write out over
and over again, as if time and labor expended in what may be termed
visual speech were of no importance. Neither has our written charac-
ter the advantage of distinctness to recommend it it is only necessary
to write such a word as minimum or ammunition to become aware
of the want of sufficient difference between the letters we employ."

National Uniformity of Weights and Measures. " Another subject
of a social character which demands our consideration is the much-de-
bated question of weights and measures. Whatever difference of
opinion there may be as to the comparative merits of decimal and duo-
decimal division, there can, at all events, be none as to the importance
of assimilating the systems of measurement in different countries.
Science suffers by the want of uniformity, because valuable observations
made in one country are in a great measure los to another from the
labor required to convert a series of quantities into new denominations.
International commerce is also impeded by the same cause, which is
productive of constant inconvenience and frequent mistake. It is
much to be regretted that two standards of measure so nearly alike as
the English yard and the French metre should not be made absolutely
identical. The metric system has already been adopted by other na-
tions besides France, and is the only one which has any chance of be-
coming universal. We in England, therefore, have no alternative but
to conform with France, if we desire general uniformity. The change
might easily be introduced in scientific literature, and in that case it
would probably extend itself by degrees amongst the commercial classes
without much legislative pressure. Besides the advantage which would
thus be gained in regard to uniformity, I am convinced that the adop-
tion of the decimal division of the French scale would be attended with

1*

VI NOTES BY THE EOITOK

great convenience, both in science and commerce. I can speak from
personal experience of the superiority of decimal measurement in all
cases where accuracy is required in mechanical construction. In the
Elswick Works [where the Armstrong guns are made. ED.], as well
as in some other large establishments of the same description, the inch
is adopted as the unit, and all fractional parts are expressed in deci-
mals. No difficulty has been experienced in habituating the workmen
to the use of this method, and it has greatly contributed to precision of
workmanship. The inch, however, is too small a unit, and it would be
advantageous to substitute the metre if general concurrence could be
obtained. As to our thermometric scale, it was originally founded in
error ; it is also most inconvenient in division, and ought at once to be
abandoned in favor of the centigrade scale. The recognition of the
metric system and of the centigrade scale by the numerous men of
science composing the British Association, would be a most important
step toward effecting that universal adoption of the French standards
in this country which, sooner or later, will inevitably take place ; and
the Association in its collective capacity might take the lead in this
good work, by excluding in future all other standards from their pub-
lished Proceedings."

In this connection it may be interesting to add that a commission of
scientists has recently been convened in Germany, to consider what
measures may be best adopted there, to secure uniformity of weights
and measures, and the various continental Governments have been
called upon to examine the practicability of those which have been rec-
ommended. The Bavarian Government states its readiness to adopt
the decimal system for weight and long measure, but in surface and
cubic measure can only promise to have tables of reduction prepared
and circulated. The land-tax, as it exists in Bavaria, is the chief ob-
stacle to any simplification of the surface scale, while the fact that there
are different measures for fire-wood, for timber, for earth and for stone
would cause great confusion if any reform of cubic measure were to be
introduced.

Accuracy of Modern Astronomical Investigations. In another part
of the present volume, attention is called to the discrepancy which ex-
ists in the estimates of astronomers respecting the solar parallax. This
has usually been represented by eight seconds and a half; but accord-
ing to the recent calculations of Hansen, the German astronomer, four-
tenths of a second should be added, which reduces the distance of the
earth from the sun about four millions of miles. At a recent meeting
of the Royal Astronomical Society (G. B.), Mr. Pritchard thus rep-

ON THE PROGRESS OF SCIENCE. VII

resented the difference : " Take a hair and measure it, .and you will
find that the correction of the distance amounts to this, that we have
to look at the hair at a distance of 125 feet. This is the correction
that astronomers have made : or, let us look at a sovereign at a distance
of eight miles ; it amounts to about the same thing. "We ought to be
thankful that we are able to calculate and correct such inappreciable
quantities."

Astronomical Memoranda. The Lalande prize of the French
Academy has been awarded to Mr. Alvan Clark, of Cambridgeport,
Mass., for his discovery of the companion star of Sirius, the great object-
glass (18 inches in diameter), with which this most interesting discovery
was made, was Mr. Clark's own manufacture, and was intended for the
observatory of the University of Mississippi. In consequence, however,
of the breaking out of the civil war, this glass was never delivered, and
has since been sold to the Astronomical Association of Chicago for
11,000 dollars. It is highly creditable to the West that such a purchase
should have been made for its busiest trading city, and we may antici-
pate that the observatory of Chicago, which has already done good
work, will achieve a reputation in the higher branches of astronomy.

At a meeting of the Royal Asiatic Society held March, 1863, Dr.
Kern produced a translation of a portion of the works of Aryabhatta, a
celebrated Hindoo mathematician of antiquity, which seemed to prove
conclusively that the sphericity and diurnal rotation of the earth had
been correctly apprehended by that early Indian writer, who flourished
at an epoch variously estimated by different investigators, but which
must have been prior to A. D. 600, and has been placed as far back as
B. c. 100.

Extension of Telegraphic Communication. During the year 1863, com-
munication by electric telegraph has taken place between London and
Turnen, in Siberia, a distance of 4039 miles. It was anticipated that
an extension of the wires will be made to Nikolaievski, on the Pacific,
by the end of 1863, and that telegraphic communication with New
York, via Siberia and California, will be established by the end of
1865.

Meteorological Science. The most important contributions to Me-
teorological Science of the year have been made through the balloon
ascensions of Mr. James Glaisher, under the auspices of the British As-
sociation. The observations of the meteorologist show that the de-
crease of temperature with elevation does not follow the law previously
assumed of 1 in 300 feet, and that in fact it follows no definite law at
all. Mr. Glaisher appears also to ha^e ascertained the interesting fact

VIII NOTES BY THE EDITOR

that rain is only precipitated when cloud exists in a double layer. Rain-
drops, he has found, diminish in size with elevation, merging into wet
mist, and ultimately into dry frog. Mr. Glaisher met with snow for a
mile in thickness below rain, which is at variance with our preconceived
ideas.

Cinchona Bark from India. The gradual but certain destruction
of the Cinchona forests of America, which has been viewed with so
much anxiety by all who know how indispensable quinine is to the ex-
istence of Europeans in many of the tropical parts of the world, may
for the future be considered of minor importance, inasmuch as the suc-
cessful cultivation of the Cinchonas in India has been demonstrated
the past year. At a meeting of the Linnean Society, London, June,
1863, the first specimens of Cinchona bark sent from India to Europe
were exhibited. It was stated that these had been found to yield a
percentage of quinine, and the other febrifuge alkaloids, fully equal
to that furnished by the bark of the same species when grown in South
America ; and it had also been ascertained that quinine might be ob-
tained in small quantities from the leaves. The successful culture of
the Cinchona plants in India must be regarded as a subject of the
highest importance, not merely to the prosperity of India, but indirectly
to the whole world ; as the exploration and civilization of many tropi-
cal countries by Europeans is absolutely dependent on a reliable sup-
ply of quinine.

Acclimatizing Efforts in A ustralia. The work of acclimatizing
European animals in Australia, under the direction of proper authori-
ties, is being pursued vigorously, and with great success. Mr. Edward
Wilson, of Melbourne, Australia, in a report on the subject, states that
the English skylark and the thrush were breeding freely in a wild state,
, and " not only making various neighborhoods vocal, but absolutely, by
force of example, compelling the native birds to improve their song-
notes." A number of fallow deer had been turned out, and taken
readily to bush life. Several kinds of English pond fish had been safely
brought over, and transferred to the native waters. A collection of
birds, amongst others the Indian vcurassow, gold, silver, and common
pheasants, Ceylon peafowl, American and other waterfowl, were being
prepared in the Botanic Gardens for transfer to wild land, and it was
thought that all would eventually thrive. The lama has been acclima-
tized and its wool has become one of the products of Australia.

Steam Cultivation. A " General Steam Cultivation Company " has
been started in London, with a capital of over a million dollars, whose
object is announced to be to purchase, keep on hand, and rent or

ON THE PROGRESS OF SCIENCE. IX

to farmers, at reasonable rates, every kind of steam agricultural imple-
ment. The prospectus suggests that many farmers would gladly use
steam in ploughing and otherwise working their soil, but cannot afford
to invest several thousand dollars in the needful machinery. To these
this company proposes to be helpful. It is asserted that applications
are already received for renting machinery to the value of quarter of
a million of dollars. A Mr. Smith, of Woolston, England, who has es-
pecially exerted himself during the last few years to promote " steam
culture," has recently published a resume of his personal experience in
this matter. He states, that the cost of preparing land for roots was,
with steam, $2.88 ; with horses, $10.03 ; for barley two years, $2.16
with steam against $5.05 by horse power ; four years for wheat, $50.20
by steam against the same for horse power, and foots up a total for a
number of other articles, which shows a gain of 200 per cent, in favor
of steam. The writer says also that besides the economy of the plan,
he had much better crops.

Novelty in Architectural Construction. A novelty in architectural
construction has been brought out during the past year in the construc-
tion of a building designed for a school of art at Nottingham, England.
The dome of the tower is to be covered, and some panels in the front
filled in with Minton's encaustic tiles, patterned in bright colors. The
London Athenceum commenting on this peculiarity says, " We cannot,
understand why, considering the exigencies of our town life and atmos-
phere, the whole exterior of a building could not be covered with ceram-
ics, comprising bands in bold relief richly moulded and colored, dec-
orated heads for windows, and friezes of figures, either relieved, or,
preferably, drawn on the flat, in an architectonic character and soberly
toned in color, either on a white or a bright-hued ground. Glazed sur-
faces are obviously the only ones fit for exterior decoration in modern
towns. Let any one look at the waste of labor on the carvings of St.
Paul's, what a stained and smeared great structure it is, or at the
Houses of Parliament, and see how the sooty streams trail over the
costly waste of mouldings and figures, and not only hide but eat them
away ; then let him consider what the latter building will be a century
hence, judging by what he sees of the piebald state of the former. Do
we not make glazed earthenware for half the planet, and can we not
cover our own houses with it ? "

Recent Progress of Chemical Science. During the past year,
through the aid of the process of spectral analysis, another new body,
Indium, has been added to the list of the elements. Bessemer's process
of manufacturing iron and steel may now be considered as having

X NOTES BY THE EDITOR

passed out from the domain of theory, into the province of actual and
practical fact. The contributions made to our knowledge by Professor
Graham respecting the molecular constitution and properties of gases,
should also be included among the important novelties of the year in
inorganic chemistry. The recent advances in organic chemistry are
thus detailed by a writer in the London Pharmaceutical Journal, Dr.
Mac Adam. He says, " Not only does the manufacturing chemistry
of the day transform starch and sugar into alcohol by fermentation, as
in brewing operations ; sawdust into oxalic acid by the action of soda
and nitre ; starch or sawdust into grape-sugar by the aid of sulphuric
acid ; wood and coal into paraffin and paraffin oils by the process of
destructive distillation ; coal into aniline and the coal-tar colors ; and
guano into a magnificent color, rivalling that from the cochineal insect ;
but the organic chemistry of the day has proceeded to produce artifi-
cially many alcohols and ethers, including jargonelle pear essence and
pine-apple essence ; and to construct many alkaloids resembling quinine,
strychnine and morphine in their-composition and chemical properties,
encouraging the hope that we may soon be in possession of the means
of preparing by artificial processes these powerful medicines, and pos-
sibly others equally efficacious. And more than that, and principally
through the researches of Berthelot, dead mineral matter has been
worked up by stages into organic compounds. Thus Berthelot, taking
carbon and sulphur, combines these into bisulphide of carbon, a mo-
bile, ethereal liquid ; and therefore, by the mutual reaction of copper,
hydrosulphuric acid, and the bisulphide of carbon, he obtains olefiant
gas. The latter is absorbed by sulphuric acid (oil of vitrol) to the ex-
tent of 120 volumes of the gas in one of the acid, and thereafter by di-
lution with water and distillation, the acid mixture yields alcohol of
the same composition and properties as that obtained from ordinary
grain. Strecker takes the olefiant gas in solution in sulphuric acid,
and by adding water, neutralizing with ammonia, evaporating and
heating, obtains crystals of taurine, one of the constituents of bile.
Wohler combines the simple elements, nitrogen and oxygen, by electric
discharges, into nitric acid, and then by the successive mutual reaction
of this nitric acid with tin, hydrochloric acid, and black lead, and lime
(or oxide of lead), he obtains a complicated organic substance, called
the hydrocyanate of ammonia. The latter may also be prepared by
passing a mixture of the gases ammonia and carbonic oxide through a
red-hot tube. The hydrocyanate of ammonia may then be employed
in yielding cyanogen, hydrocyanic acid (prussic acid), oxalic acid, and
urea ; also formic acid, paracyanogen, cyanuric acid, sulphocyanogen,
and mellon.

ON THE PEOGEESS OF SCIENCE. XI

" When cast-iron (which contains carbon) is dissolved in dilute sul-
phuric or hydrochloric acid, there is evolved a volatile oil resembling
turpentine, and there is left in the vessel a small quantity of graphite,
and a brown mould resembling vegetable mould. Ordinary carbonate
of soda (washing soda) can have carbon extracted from it, and if the
latter is acted upon by dilute nitric acid, and the solution evaporated,
an artificial tannin is obtained, which has the property of precipitating
gelatine or glue from its solution, like ordinary tannin obtained from
gall nuts or oak bark. Berthelot has taken carbonic oxide and caustic
potash, and compelled them to produce formic acid (yielded naturally
by red ants) ; and with a single link of the chain awanting, he has
manufactured glycerine, which is the base of fatty substances, and com-
bining it with the fatty acids, he has prepared artificially the oils and
fats generally obtained from the plant and the animal, and many more
new oils and fats not known in nature. Berthelot has acted upon gly-
cerine by putrefying animal matter, and obtained artificially grape
sugar ; and has converted oil of turpentine into ordinary camphor and
Borneo camphor ; whilst, in conjunction with De Luca, he has prepared
artificially one of the chief constituents of oil of mustard (sulphocyanide
ofallyl).

" These researches in organic chemistry may appear, at this, the mo-
ment of their birth, to have little influence on the arts and manufac-
tures and on mankind in general. But are they not researches into
the deep mysteries of nature ? and who can predict the influence which
they rnlfcy yet have on the prosperity of the human race ? "

Change of Color in Stars. It is more than suspected by some of
the European astronomers that an example of a star successively
changing its color may now exist in the stellar body known as ninety-
jive Herculis. Mr. Higgins, in his observation on Spectra of Stars,
has had occasion to notice the phenomena, and he describes the
change as observable, even after intervals so brief as three or four
nights.

The so-called Spiritual Phenomena. A recognition of the reality
of many of the phenomena physical or physiological which are
popularily classified under the term " Spiritual " appears to be gradu-
ally gaining ground among the scientific men of the United States
and Europe. Among the names of note who are reported during the
past year as having extended such a recognition, we find that of Prof.
De Morgan, who is confessedly one of the most distinguished of liv-
ing British physicists and mathematicians. The position which this
gentleman and others assume is probably well expressed in the follow-

XII NOTES BY THE EDITOR.

ing extracts of a letter recently published in the London Athenceum.
This observer savs :

" I divide, for brevity sake, all the phenomena into physical and meta-
physical, a division which, if not strictly philosophical, will be suffi-
ciently understood by those who have been present at any so-called
sitting. My testimony, then, is this : I have seen and felt physical
facts wholly and utterly inexplicable, as I believe, by any known and
generally received physical laws. I unhesitatingly reject the theory
which considers such facts to be produced by means familiar to the
best professors of legerdemain. I have witnessed also many very sur-
prising and extraordinary metaphysical manifestations. But I cannot
say that any of those have been such as wholly to exclude the possibil-
ity of their being deceptive, and indeed, to use the honest word
required by the circumstances, fraudulent. This is my testimony
reduced to its briefest possible expression.

" If it be asked what impression, on the whole, has been left on my
mind by all that I have witnessed in this matter, I answer, one of per-
plexed doubt, shaping itself into only one conviction that deserves the
name of an opinion, namely, that quite sufficient cause has been shown
to demand further patient and careful inquiry from those who have
the opportunity and the qualifications needed for prosecuting it ; that
the facts alleged, and the number and character of the persons testify-
ing to them, are such that real seekers for truth cannot satisfy them-
selves by merely pooh-poohing them."

Interesting Report on Fisheries. An interesting instance of a
governmental inquiry, under scientific auspices, into a branch of natu-
ral industry, has been presented to us during the past year, in a re-
port to the British Parliament, of a commission appointed to consider
and investigate the subject of the herring fishery, particularly as it
is connected with British interests. This commission consisted of Col.
Maxwell, Dr. Lyon Playfair, and Mr. T. Huxley ; and the following
is a resume of the more important features of the report in question.
The conclusion is arrived at, that the herring does not, as some natu-
ralists have affirmed, migrate to the seas within the Arctic circle, but,
probably, on disappearing from the shores of the British Islands, passes
into dejep water near them. The herring is found under^four different
conditions: 1st, Fry or Sill; 2d, Maties, or Fat Herring; 3d,
Full Herring ; 4th, Shotten, or Spent Herring. It is extremely diffi-
cult to obtain satisfactory evidence as to the length of time which the
herring requires to pass from the embryonic to the adult or full con-
dition. The commissioners, after considering all the evidence obtain-

ON THE PROGRESS OF SCIENCE. XIII

able, are of the opinion, that the herring attains to full size and matu-
rity in about eighteen months. It is also probable that this fish arrives
at its spawning condition in one year, and that the eggs are hatched
in, at most, two to three weeks after deposition, and that in six or
seven weeks more the young have attained three inches in length. The
maties, or fat herring, feed, develop their reproductive organs, and be-
come full herrings in about three or four months. The herrings then
aggregate in prodigious numbers for about a fortnight in localities
favorable for the reception of their ova. Here they lie in tiers, cover-
ing square miles of sea bottom, and so close to the ground that the
fishermen have to practise a peculiar mode of fishing in order to take
them, while every net and line used in the fishing is thickly covered
with the adhesive spawn which they are busily engaged in shedding.
So intent are the fish on this great necessity of their existence that
they are not easily driven from their spawning ground ; but when once
their object has been attained, and they have become spent fish, the
shoal rapidly disappears, withdrawing in all probability into deep water
at no great distance from the coast. There is no positive evidence as
to the ultimate fate of the spent herrings ; but there is much to be
said in favor of the current belief, that after a sojourn of more or less
duration in deep water, they return as maties to the shallows and lochs>
there to run through the same changes as before. The commission-
ers were unable to gain any information respecting the time which
one and the same herring may pass through the cycle. The enemies
of this fish are, however, too numerous and active to render it at all
likely that the existence of any one fish is prolonged beyond two or
three reproductive epochs. Great difference of opinion has been held
respecting the spawning season of the herrings. The commissioners'
conclusion is, that the herring spawns twice annually, in the spring
and in the autumn. It is not, however, at all likely that the same fish
spawn twice in the year ; on the contrary, the spring and the autumn
shoals are most likely perfectly distinct; and if the herring, as is
probable, comes to maturity in a year, the shoals of each spawning
season would be the fry of the twelvemonth before.

The food of the herring consists of Crustacea, varying in size from
microscopic dimensions to those of a shrimp, and of small fish, particu-
larly sand-eels.

The commissioners ascribe the remarkable variableness in the
annual visits of shoals of herrings to the British coasts to the varying
quantity of food of the fish, and to the number and force of the
destructive agencies at work. Any circumstance which increases or

XIV NOTES ON THE PKOGBESS OF SCIENCE.

decreases the quantity of Crustacea and sand-eels must exercise great
influence on herring-shoals ; but these are even more acted upon by
their great destroyers. The latter may be ranged under the heads of
fish, birds, marine animals, and man. Of these, by far the greatest de-
stroyers are fish and marine animals, as porpoises and other cetacea.
It is estimated that the total annual take of herrings by British fisher-
men is 900,000,000 ; a prodigious number ; but great as this is, it sinks
into comparative insignificance when compared with the destruction
effected by other agencies. Cod alone destroy ten times as great a
number as are captured by all our fishermen. It is a very common
thing to find a cod-fish with six or seven large herrings in his stomach.
When it is further considered that the conger and dog-fish do as much
mischief as the cod and ling, that the gulls and gannets slay their mil-
lions, and that porpoises and grampuses destroy additional countless
multitudes, it will be evident that fishing operations, extensive as they
are, do not destroy five per cent, of the total number of full herrings
that are destroyed every year by other causes. These facts, which
cannot be controverted, prepare us for the conclusions arrived at by
the commissioners with reference to the legislative enactments relating
to the herring fishery.

They recommend that all prohibitory or restrictive laws bearing on
the herring fishery be repealed, and that the fishermen be allowed to
follow their business in any manner they may think proper. In con-
clusion they add : "If legislation could regulate the appetites of cod,
conger, and porpoise, it might be useful to pass laws regarding them ;
but to prevent fishermen catching one or two per cent, of herring in
any way they please, seems, in the opinion of the Commissioners, a
wasteful employment of the force of law."

We present to the readers of the Annual of Scientific Discovery for
1864, the portrait of Major-General Q. A. GILLMORE, U. S. A., best
known in science for his investigations and researches respecting
"limes, mortars, and cements," and for the brilliant military engineer-
ing displayed by him in the reduction of Forts Pulaski, Sumter, and
Wagner.

THE

ANNUAL Or SCIENTIFIC DISCOVERT.

MECHANICS AND USEFUL ARTS.

THE SEWERS OF PARIS.

THE present system of sewerage in Paris, decreed by the Emperor
Napoleon III. in 1852, consists of six main galleries, called collectors,
fifteen secondary ones opening into the former, and themselves fed by
a vast number of smaller ones intersecting the city in every direction.
Three of the collectors are located upon the right bank of the Seine,
and three upon the left bank. The united length of the former is
8.GOO metres; of the latter, 9.200 metres.

The ratio of the section to be given to the various sewers has been
fixed, as experience required, at from two to three square metres of
wet surface for every 100 hectares. On this principle, twelve different
sizes have been chosen, the smallest having a section of 2.15 metres in
height by 1.15 in breadth, and the largest one of 4.40 metres in height
by 5. GO in breadth. The former is of an ovoid shape, and offers ample
space for a man and a wheelbarrow. The largest sewer or collector
has a circular segment for its section ; its breadth is divided into three
parts, the two lateral ones being foot pavements, and the middle one a
gutter or drain 1.20 metres broad. On each foot pavement, a series of
iron forks support a water pipe, varying in diameter from 1.10 metres
to 0.80. In some of the galleries there is but one water-pipe. To
cleanse the drain a small cart, running on iron rails laid along the bot-
tom, is pushed forward by two men ; the front of this cart is provided
with a drop-plank, acting like a sort of sluice, which, when down,
exactly closes the section of the gutter, and pushes all the mud before
it as the cart advances. By the sewers above described, all the foul
waters of the right bank are easily brought to the Place de la Con-
corde, where a general collector receives them and carries them off to
Asrueres. But what was to be done with the sewerage of the left bank,
which, according to the system adopted, was also to be poured into the

15

16 ANNUAL OF SCIENTIFIC DISCOVERY.

general collector. After much reflection, It was decided that the waters
of the left bank should be carried over by a siphon passing under the
bed of the Seine ; and this singular engineering feat has actually been
accomplished. An enormous pipe of wrought iron having an interior
diameter of one metre, and about 200 metres in length, is sunk, a little
above the Pont de la Concorde, two metres below the low-water mark,
and thus the desired communication is established. As to the general
collector, it is the most stupendous work of the kind in existence. It
is 5 metres in height by 5.G1 in breadth, with a length of about five
kilometres and a half, in nearly a right line, except a turn under the
Place de la Madeleine. The foot pavements are 1.90 metres on each
side, the central drain is 3.60 metres in breadth, with a depth of 1.35 ;
so large, in fact, that a well sized boat is kept afloat on it for the pur-
pose of cleansing. This boat is also provided with a drop-plank in
front; this is let down to a distance of 15 centimetres from the bottom,
while the boat advances, whereby such a head of water is obtained in
front as to drive all the sedimentary matter nay, even stones to a
distance of 100 metres. There the boat finds it again as it advances,
and drives it further and further, till the orifice of the emissary is
reached. Four boats perform this work, and it takes sixteen days to
cleanse the whole length. Ventilation is provided for by air-traps at
certain distances, and the gallery is lighted with oil lamps. The exe-
cution of this immense system of sewers has cost fifty millions of francs.
M. Dezobry, comparing this gallery with the far-famed Cloaca Maxima
of Rome, shows that it is infinitely superior to it in size, not to mention
the improvements in construction, of which the Romans had no idea.
The Cloaca Maxima is two metres in height, and only 4.48 broad, and
is supposed never to have exceeded a length of 900 metres. The di-
mensions we have given abundantly show how vastly superior the
modern French construction is to the ancient Roman one.

THE NEW SEWERS OF LONDON.

It is well known to our readers (See Annual Sci. Dis., 1859-60)
that for the last few years, there has been in the course of construction
in London, a system of sewage, of such magnitude as to form one of
the marvels of modern engineering, and of such cost, as but few cities
could afford to pay for. The. object of the scheme is to do away with
the present plan, whereby all the enormous drainage of London is dis-
charged into the Thames; a plan which has latterly converted the
river itself into one vast sewer, to the great annoyance and sanitary
detriment of the vast population contiguous to its waters. " At the very
first glance," says the London Times : " This arrangement seems bad
enough, though it is infinitely worse when we come to examine how it
was arranged to work. On both sides of the river the banks are very
little above high-water mark, while the average level of the ground im-
mediately behind them is much below it ; half Lambeth and Rothcr-
hithc being six feet below high-water level. Of course, when this is the
level of the ground, the sewers arc much lower still, and their outlets so
completely tide-locked that it is only at dead low-water that they can
empty themselves at all. Thus, for nearly eighteen hours out of the
twenty-four, the sewage on both sides of London is to an immense ex-
tent, pent up, giving off its miasma into every street and house. As

MECHANICS AND USEFUL ARTS. 17

we have said, it could only escape at dead low water, when the return-
ing tide immediately churned it up the river, keeping all its abomina-
ble 'flotsam and jetsam' above bridge till the tide ebbed out, finding
200,000 or 300,000 gallons of filth to be operated upon in a similar
manner on its return. This was the arrangement twelve years ago,
and is almost entirely so still ; but, even bad as this was, it was capa-
ble of being made worse, and worse accordingly it was made. In
1849, most of the houses in London had cesspools attached to them,
and a very large proportion were without any drains at all. The
alarming nature of this evil showed itself slowly but surely in the Bills
of Mortality, and the then Commissioners of Sewers, who were feebly
battling with the evils of the drainage system, set to work to mitigate
the cesspool danger by drainage, making the Thames, as usual, the
general receptacle. From thtit time to the present some 700 or 800
miles of new drains have been made, and all cesspools made to drain
at once into the river. By this ' improved ' drainage some 200,000
additional gallons of sewage were daily added to the Thames at low
water, containing no less than 300 tons of ' organic matter,' which in

' ^^ C^

this case is the scientific term of filth. The result, as a matter of
course, has been that in the summer months the stench from the river
has occasionally been intolerable. In 1857, great quantities of lime
and chloride of lime were put in daily; in 1858, the same expedient
had to be resorted to again ; and in 1859, the dose had to be increased
into 110 tons of lime and 12 tons of chloride of lime, costing 1,500/.
per week. Even in a pecuniary point of view, however, this was not
the only evil of the system. The Thames in hot weather runs short
of water ; and when there is no rain, the collections of refuse in the
sewers have to be flushed into the river by artificial means. This
flushing alone during summer costs 20.000/. a year to get the poison
into the TTiames, where 20.000/. more is generally required to keep it
from breeding a plague." To obviate these difficulties, an immense
new sewage system was devised, and for the last few years has been in
the course of construction, whereby London will be effectually drained,
and the Thames purified. As may easily be imagined, it is impossible,
in an article like the present, to give more than an outline of this great
plan, which- may best be briefly described as consisting of three gigan-
tic main tunnels or sewers on each side of the river. These completely
divide underground London, from west to east, and cutting all existing
sewers at right angles intercept their flow to the Thames, and carry
every gallon of London sewage under certain conditions into the river
at a point far below the city limits and not far distant from the sea.
" These main drains are called the High, Middle, and Low Level sew-
ers, according to the height of the localities which each respectively
drains. The High Level, on the north side, is about eight miles in
length, and runs from Hainpstead to Bow, being at its rise only four
feet six inches in diameter, and thence increasing in circumference, as
the waters of the sewers it intercepts require a wider course, to five
feet, six feet, seven feet, ten feet six inches, eleven feet six inches,
and at its termination to twelve feet six inches in diameter. This
drain is now entirely finished, and in full work. Its minimum fall is
twelve feet in the mile ; its maximum at the beginning nearly fifty
leet a'inile. It is laid at a depth of from twenty to. twenty-six feet be-
2*

18 ANNUAL OF SCIENTIFIC DISCOVERY.

i

low the ground, and drains an area of fourteen square miles. The
Middle Level, as being lower in the valley on the slope of which Lon-
don is built, is laid at a greater depth, varying from thirty to thirty-six
feet, and even more below the surface. This is nearly complete, and ex-
tends from Kensal Green to Bow. The Low Level will extend from
Cremorne to Abby Mills, on the marshes, near Stratford. At Bow, the
Low Level waters will be raised, by powerful engines, at a pumping sta-
tion, to the junction of the High and Middle Level ducts, thence descend-
ing by their own gravity through three tunnels to the main reservoir and
final outfall. These three tunnels are each nine feet six inches in diam-
eter, and nearly four miles long. Great engineering difficulties existed
in the construction of these main arteries, as, from the height at which
they all meet, it was necessary to take them above the level of the marshes
leading to Barking For a mile and a half the embankment which en-

^^ ^j

closes the three tunnels is carried on brick arches, the piers going eighteen
feet below the surface, and being based on solid concrete. In the marshes
at Barking, a reservoir for the reception of the sewage of the north
side has been formed. This reservoir is a mile and a half long by one
hundred feet wide, and twenty-one feet deep. It is made of this great
length in proportion to Avidth to allow of its being roofed with brick
arches, which are again covered with earth to a considerable thick-
ness, so that not the slightest smell or escape of miasma can take
place. This is capable of containing more than three times the
amount of sewage which can enter it while the pipes are shut, and
thus, when all is complete, the works will not only be large enough to
take off all London's sewage now, but its sewage when London is
double its present size.

"While the sewage is in the reservoir we have spoken of, it will be
completely deodorized by an admixture of lime. When the tide is at
its height the sluices which pass from the bottom of the reservoir far
out into the bed of the river will be opened, and the whole allowed to
flow away. It takes two hours thus to empty the reservoir, by which
time the tide will be flowing down strongly, and will carry its very last
gallon a distance of thirteen miles below Barking, which, being itself
thirteen miles below London, will place the contents of the sewers,
every twelve hours, twenty-six or more miles distant from the metrop-
olis. Thus, instead of letting loose the rankest of this great city's
abominations in the very midst of London, and leaving it to stagnate,
or, still worse, to be agitated backwards and forwards in a small body
of water, it will all be'carried away a distance of thirteen miles, then
deodorized, then suffered to escape into a body of water more than a
hundred times greater than that into which it now crawls, and thus
disinfected and diluted, so as to be without either taste or smell, swept
still further down the stream, till every trace of it is lost.

" On the south side, the three great sewer arteries are constructed on
similar plans, - - the High Level, from Dulwich to Deptford ; the Mid-
dle, from Clapham to Deptford ; and the Low Level, from Putney to
Deptford. At this point is a pumping station, which raises the water
from the low to the high level, whence it flows away through a ten feet
tunnel to Crossness Point. One part of this tunnel, passing under
Woolwich, is a mile and a half in length, without a single break, and
driven at a depth of eighty feet from the surface. At the outfall will

MECHANICS AND USEFUL ARTS. 19

be another pumping "station, to lift the water to the reservoir. The
southern reservoir is only five acres in extent ; that on the north is
fourteen. In the reservoir it will be deodorized and discharged in a
similar Avay to that we have already described.

" The pumping stations will each consist of an engine-house, contain-
ing ten boilers calculated to work up to five hundred horse-power nom-
inal. This power, working through eight pumps of seven feet diameter
and four feet stroke, will "daily raise 119,000,000 cubic feet of sewage
from nineteen feet below low water to the level of the outfall ; but, in
case of necessity, the pumps can raise 250,000,000 cubic feet per day.
The reservoir into which it will all flow is not yet finished, but when
roofed in with brick will hold 20,000,000 gallons of sewage.

" The total length of the three rows of intercepting sewers, the course
of which we have sketched on each side of the river, will be fifty
miles, and before all the works are completed 800,000 cubic yards of
concrete will be consumed, upwards of 300,000,000 of bricks, and
4,000,000 cubic yards of earthwork."

During the past year, a part of this great work has been so far com-
pleted, that a portion of the sewage of London has been diverted from
its old channels.

UNSHAKABLE TIMBER SHIPS.

At the last meeting of the British Association, Admiral Belcher stat-
ed that many years since, Mr. Walters, an architect, tried to render
ships for mercantile purposes unsinkable, by introducing copper cylin-
ders between the timbers, the hold-beams, and, indeed, every opening
where the cargo did not prevent ; and he calculated that these dis-
placements or cells would about compensate for difference of specific
gravity between cargo, vessel, and gear, so as to simply reduce her to
the state of a water-logged craft, to save crew, vessel, and such portions
of cargo as might be secured in air-tight vessels.

Latterly, the pneumatic trough had suggested itself to his (Admiral
Belcher's) mind the propriety of close-ceiling the holds, or under-
planking the hold-beams, and saving those spaces between them for
the storage of light dry-goods above that deck (which was generally
lost), ancf placing loose planks (indeed, as we were in the habit of
hatching many, of our brigs of 386 tons and under) as a temporary
deck. Now, in the event of a dangerous leak, or even a large hole being
stove in the bows or bottom of a ship, he proposed securing the hatches
from beneath to hatches above, screwed firmly in opposition to each
other, and filled in by pitch from the upper or open hatch. Now, it
would be apparent that if the ship was air-tight, the water could only
enter so long as the air was compressible, and by inverting the pump-
boxes and rendering them air-pumps, the leak would not only be
stopped, but, by the continued action of the air, it would be expelled by
the very orifice by which it entered. Therefore, the customary and con-
tinued labor and wear of the powers of the crew would not be required
to such an extent, if at all, when once the necessary quantity of air
had been forced in. He came now to the use of iron plates in forming
air-tight cellular vessels, and he hoped to 'be able to show that, by
pursuing this mode of construction, a vessel would not only be very
much less liable to injury by collision with a ram, but if carefully and

20 ANNUAL OP SCIENTIFIC DISCOVERY.

scientifically fitted, might be overrun by an adversary, and come up
on the other side. He claimed the introduction into the navy of the
air-tight compartments, by constructing a vessel upon the plan of a
ship within a ship the outer, sectional compartments each independ-
ent per se for coals or stores ; the inner to contain compartments and
accommodation, if necessity demanded, for the crew. The oval form
would secure the means of withstanding, externally, any compression ;
it would facilitate the delivery of coals from the bunkers, and if any
one of those bunkers was perforated or stove, you possessed the en-
gine-power, to be exerted from within, of expelling the water, by
ibrcing- in air, making every such valve self-acting from the interior.

STEERING SCBEW FOR STEAMERS.

Some experiments have recently been made by the British Admiralty
on a new arrangement of that screw propeller which has for its object
steering, as well as the propulsion of a vessel. ' The peculiarity of the
screw is that a universal joint is placed within the hollow boss of the
screw, which is thereby connected with the main shaft, the centre of
gravity of the screw and the centre line of the rudder intersecting
the centre line of the main shaft, so that the entire weight of the
screw is borne by the shaft ; and by means of a tail or spindle to the
screw, projecting from the boss working in the rudder, or an iron car-
rier in lieu of rudder, whatever may be the movement of the tiller or
wheel, it communicates an equal movement to the screw, which be-
comes not only the propelling but also the guiding power of the ship. One
of these screws, fitted to a naval steamer of sixty-horse power, has been
tried upon the Thames, and the result is reported in the London Post,
as unequivocally satisfactory, "clearly demonstrating that it is no
longer needful to apply double screws, hydraulic steering apparatus,
or add any other extra complications to the machinery of a steamer,
when by a wave of her own screw, her motion can be directed and con-
trolled at will."

RAILWAY TUNNELS IN GREAT BRITAIN.

At a recent meeting of the Institution of Civil Engineers, Mr. J. S.
Eraser stated that the aggregate length of the tunnels, now daily
traversed by railway trains in the united kingdom, amounts to eighty
miles ; and, supposing their cost to have been on an average fifteen
pounds per lineal yard, their construction must have caused the ex-
penditure of six and a half millions sterling.

STEEP RAILWAY INCLINE.

The Bhore Ghaut Incline of the Great Peninsular Railway of India
has occupied more than seven years in construction, and during the great-
er part of that time there have been 45,000 workmen daily employed
upon it. The incline is a series of tunnels through mountains of
rock, and viaducts stretching across valleys, alternating with each
other; each part a triumph of modern science and skill.

The incline reaches at one long lift the height of 1,832 feet, the
highest elevation yet attained by any railway incline. It is lo^ miles
long, and its average gradient consequently 1 in 4G.39. The highest
gradient is one in 37, and the sharpest curve 15 chains radius. The

MECHANICS AND USEFUL AHTS. 21

tunnels are twenty-five in number, the greatest length of any of them
being 34 H yards. There are eight viaducts, one consisting of eight
arches of 50 feet and being 129 feet high, and another, of a like num-
ber of arches, with a maximum height of 143 feet. The quantity of
cutting amounts to 2,067,738 cubic yards, and of embankments to
2,452,308 cubic yards. There are twenty-two bridges of various spans,
and seventy-four culverts. The total cost of the works has been
1,100,000," or 68,750 a mile.

STEAM BOILER EXPLOSIONS.

AVith reference to these destructive accidents, Dr. Joule, at a recent
meeting of the Philosophical Socie-ty, of Manchester, England, stated
his belief that, in nearly every -instance, rupture took place simply be-
cause the iron, by wear or otherwise, had become unable to withstand
the ordinary working pressure. Various hypotheses, set up to account
for explosions, were worse than useless because they diverted attention
from the real source of danger. He believed that one of these hy-
potheses that which attributed explosions to the introduction of water
into a boiler, the plates of which were heated in consequence of de-
ficiency of water-- was quite inadequate to account for the facts; al-
though weak boilers might be exploded at the moment of starting the
engine, in consequence of the swelling of the water through renewed
ebullition throwing hot water over the heated plates. The absolute
necessity of employing the hydraulic test periodically had been point-
ed out so frequently that he considered that the neglect of it was
highly criminal.

UTILIZATION OF THE TIDES.

Let us suppose (says a writer in the Chemical News') that by the action
of the tides, the difference of level of the surface of the ocean at a cer-
tain spot is twenty-one feet between high and low water. Omitting for
the present all consideration of the power of the subjacent liquid,
what is the mechanical value of a space of one hundred yards square
of this water? One hundred yards square by twenty- one feet deep,
equal 70,000 cubic yards of water, which is lifted to a height of twenty-
one feet, or to 1.470,000 cubic yards lifted to a height of one foot.
Now, since one cubic yard of water weighs about 1 G83 pounds, 1,4 70,000
cubic yards weigh 2,474.010,000 pounds, which is lifted in six hours.
This is equivalent to lifting a weight of 412,335,000 foot pounds in
one hour ; and since one-horse power is considered equivalent to rais-
ing 1,800,000 foot pounds per hour, w r e have, locked up in every one
hundred yards square of sea surface, a power equal to a two hundred
and thirty horse power steam-engine ; acting, be it remembered, day and
night to the end of time ; requiring no supervision ; and costing nothing
after the first outlay but the wear and tear of machinery. By means
of appropriate machinery connected with this tidal movement, any
kind of work could be performed readily.

THE PNEUMATIC DESPATCH.

In the Annual of Sci. Dis. 1863, p. 43, the application of the prin-
ciple of forcing packages through tubes by atmospheric pressure to the
conveyance of mail-bags in London, to and from, the District Post

22 ANNUAL OF SCIENTIFIC DISCOVERY.

Office and the Euston Street Railway station (a distance of 1800 feet)
was described as about to be put in practical operation. A recent
report of the Pneumatic Despatch Company now states, " That
since the 20th of February, 18G3, the authorities have discontinued
their street conveyances, and intrusted the company with the trans-
mission of the mails, and that the service of the district had since
been entirely performed by the company. Thirty trains per diem
(Sundays excepted) have been despatched with perfect regularity,
and upwards of 4,000 trains have run without impediment or delay.
The time occupied in the transmission has not exceeded seventy sec-
onds. The daily cost of working has averaged l. 4s. 5d. ; and five
times the number of trains could have been conveyed without any
appreciable increase of expense."

The successful result of these experiments has induced the com-
pany to proceed to the laying of an additional line of pipe for further
post-office accommodation, which will be 2|- miles in length and 54
inches in diameter, at an estimated total cost of 65,000. It is confi-
dently predicted that, in the course of a few years, the entire trans-
mission of the London mails throughout the city will be accomplished
by atmospheric pressure.

IMITATION RUSSIA SHEET IRON.

At a recent meeting of the Franklin Institute, Prof. Fleury pre-
sented specimens of imitated Russia sheet iron, made under the patent
of Mr. Win. Riesz from ordinary rolled iron, the original cost of which

* ^3

was 5 cents per pound ; the expense of the process was 2^ cents, mak-
ing the total cost of the iron in its present condition, 7 cents per
pound. He stated that " the inventor, who was for a number of years
director of a large iron manufacturing establishment in Germany, had
made it his particular study to examine theoretically and practically
the manufacture of the iron which was imported in large quantities
from Russia. By repeated analyses of the iron, and also through no-
ticing its beautiful, smooth, and incorrodible surface (by scraping off*
the surface from a large number of sheets), he came to the curious con-
clusion that the Russia iron was not, as he had thought, and as the gen-
eral impression among iron manufacturers still seems to be, covered by
a film of carburet of iron, but that the smooth surface consisted of an
atomic accumulation of a peculiar substance, a NITRIDE of iron com-
bined with about 20 per cent, of carbon: the nitro-carburetted iron of
Fremy. The quantity of carbon and nitrogen diminished gradually
towards the centre, where the iron was nearly pure and very flexible.
After years of experiments, he has finally succeeded in producing from
ordinary sheet iron the best imitation of Russia sheet iron which, in
iny opinion, can be made."

" Though the process is very simple, it requires considerable skill ;
but once learned, by short practice under the guidance of the inventor,
it can be carried on in the most regular manner. The iron is cleaned
in a sulphuric acid bath, then washed with an alkali and water, and
placed in a peculiar mixture described in the patent, which prevents
oxidation ; it is then rolled with the before-named coating, and, after
being re-heated, placed under the hammer to receive the required tem-
per and smoothness."

MECHANICS AND USEFUL ARTS. 23

PROTECTION OF IRON FROM RUST.

At a recent meeting of the Society of Arts, London, the question of
preserving iron from rusting formed a subject of conversation. It was
stated that galvanized iron wire for telegraphs was not affected with
rust in passing through the rural districts of England ; but that the
coating of zinc on the iron afforded no protection to wires in cities.
The acid gas generated by the combustion of fuel attacked the coating
and decomposed it. A new substitute for covering telegraphic wire
was desirable.

With respect to paints for coating iron, such as the plates of iron
vessels, machinery, &c., Mr. John Braithwaite stated that pure red lead
was the best. His experience dated as far back as 1806, with the use
of red lead, and for fifty years he had used it with success. White
lead was more injurious than beneficial as a paint for iron. In April
last, he inspected a well, two hundred feet deep, a short distance out of
London, where he had put up an engine forty-five years ago ; the long
iron rods which had been placed in it had been painted with red lead,
and the metal had remained unchanged in all that period. The same
preservative effects of red lead paint on iron, he had witnessed upon
other iron-work which had been many years in use.

ALUMINUM BRONZE.

It has long been an object with scientific inquirers to reduce the
weight of the philosophical instruments which they have to employ.
Especially is this the case with magnetical and astronomical instru-
ments used in the triangulation of a country for a survey, or the highly
important operation of measuring an arc of the meridian. Aluminum
bronze supplies the long-sought desideratum. This metal is produced
from a mixture of ten per cent, of aluminum with pure copper ; and a
most remarkable metal it is. Col. Strange, in a recent communication
to the Royal Astronomical Society, thus enumerates some of its proper-
ties: Good gun-metal will break with a strain of 35,000 Ibs. to the
square inch; aluminum bronze requires 73,000 Ibs to the square inch
to break it. It resists compression equally well ; it is malleable when
heated ; can be easily cast, and behaves well under the file. " It does
not clog the file ; and in the lathe and planing-machine, the tool re-
moves long elastic shavings, leaving a fine, bright, smooth surface."
Moreover, " it can be worked with much less difficulty than steel ; tar-
nishes less readily than any metal usually employed for astronomical
instruments, and is less affected by changes of temperature than either
gun-metal or brass." This latter quality is especially important in in-
struments used for surveying in the tropics, as expansion by heat would
very much impair their accuracy. It is remarkably well fitted to re-
ceive graduation, as it takes a fine division, which is pure and equable,
surpassing any other cast metal in this respect. Col. Strange remarks
that in its elasticity it is said to surpass even steel, and it would there-
fore appear to be the most proper material for the suspension strings of
clock pendulums.

C. Tissier, Director of the Aluminum Works at Rouen, shows that
one per cent, of aluminum in copper makes the latter more fusible,
giving it the property of filling the mould in casting, at the same time

24 ANNUAL OF SCIENTIFIC DISCOVERY.

preventing it from rising in the mould. The action of chemical agents
upon it is also weakened, and the copper gains in hardness and tena-
city without losing its malleability, thus producing an alloy which has
the malleability of brass, with the hardness of bronze.

Aluminum bronze has been selected by Col. Strange as the most ap-
propriate metal for the construction of the large theodolite for the use
of the Trigonometrical Survey of India. The horizontal circle of this
theodolite, is three feet in diameter, and the effect of using this alloy
will be to keep the weight of the instrument within reasonable limits,
notwithstanding its possession of means and appliances not hitherto
bestowed on such instruments. In the manufacture of the alloy, Col.
Strange says that extremely pure copper must be used; electrotype
copper is best, and Lake Superior copper stands next, giving an alloy
of excellent quality. The ordinary coppers of commerce generally
fail, owing, it is said, to the presence of iron, which appears to be spe-
cially prejudicial. Further, the alloy must be melted two or three
times, as that obtained from the first melting is excessively brittle.
" Each successive melting, up to a certain point, determined by the
working, and particularly the forging properties of the metal, improves
its tenacity and strength." The present price of English-made 10 per
cent, aluminum bronze is 6 shillings 6 pence per Ib. This is four or
five times that of gun-metal.

MALLEABLE IRON NAILS.

There is a description of nails of cast malleable iron coming into use
for fixing slates on to the roofs of factories and similar buildings. They
oxidize much less in damp air than common iron nails, or even copper
ones. To manufacture them, very hot metal is run into ordinary sand
moulds. These malleable iron nails are very brittle before being placed
in the annealing furnace. Their sojourn in the furnace renders them
very ductile. They are then put into polishing barrels, in which they
are cleaned, whereupon they are thrown into a zinc bath to obtain
a coating. London Mechanics' Magazine.

IMPROVEMENT IN STEEL WORKING.

Mr. Anderson, Assistant Superintendent of Woolwich Arsenal, an-
nounces the discovery of a simple process by which steel is rendered as
tough as wrought-iron without losing its hardness. This change is ef-
fected in a few minutes by heating the metal and plunging it in oil,
after which the steel can be bent, but scarcely broken. The value of
this discovery will be at once appreciated by those who are aware of
the difficulties hitherto experienced in obtaining a suitable material for
the interior tubes of built-up guns.

FILES MADE BY MACHINERY.

The manufacture of files by machinery is said to have been success-
fully commenced in Birmingham, England. The blanks are forged by
machinery, and they are then cut with the French machine of M. Ber-
not. The machine, which is very compact, resembles a small steam-
hammer in its general appearance. It is provided with a vertical slide,
carrying a chisel on the lower end. The top of this slide is pressed by
a flat spring, which is governed by a cam mounted upon a shaft, and

MECHANICS AND USEFUL ARTS. 25

actuated by a ratchet wheel and pawl ; and thus the strength of the
blow of the chisel is regulated to the varying breadth of the file. A
projection at the other end of the slide comes in contact with a cam
upon the driving shaft of the machine, and so sets the machine in mo-
tion. The blank to be cut is placed upon a travelling slide, .resting
upon a semicircular bed, which is mounted in trunnions resting upon
swivelling journals, so that the surface of the blank can be presented
at the desired angle to the chisel. The blank is held parallel to the
edge of the chisel by means of a weighted " leveller." All being
ready, the file is fixed in the bed, the machine is set in motion, and
presently the file runs out cut. The chisel makes from 800 to 1,500
cuts per minute, and will produce about five or six times the amount of
work which can be supplied by hand-cutting. A comparison of the
two modes of cutting hand and machinery, shows that, while a
machine, to cut fourteen-inch hard files, makes 1,000 cuts per minute,
or 600,000 cuts per day, a good file-cutter, upon the same size and
description, could only make 140 cuts per minute, or 84,000 per day.

COPPER PAINT.

A paint prepared by M. Oudry, of Paris, from electrotype copper re-
duced to an impalpable powder (by the aid of a steam-hammer), and
diffused in varnish, is, undoubtedly, a most important industrial discov-
ery. The preparation of the color is not difficult and not expensive.
It is stated to be susceptible of easy application to wood, plaster, cem-
ent, brass, or iron, and also to the hulls of ships. It forms a perfect
covering, dries rapidly, and takes an agreeable lustre susceptible of re-
ceiving, by means of chemical agents, the tone of bronze, bright or
dark, verd-antique, or Florence green, which has never before been
communicated to pure copper. Ornaments in brass or statues in plas-
ter, when painted in this manner, lose none of their most delicate de-
tails, and they assume completely the appearance of objects in bronze.
Even statues in plaster appear to resist remarkably inclement condi-
tions of the atmosphere. By mixing the powder of galvanoplastic cop-
per with certain fatty oils, Oudry obtained very beautiful greens of
varied hues.

REPAIRING THE SILVERING OF LOOKING-GLASSES.

The repairing of the silvering on the backs of looking-glasses has
hitherto been considered a very difficult operation. A new and very
simple method, however, has been described before the Polytechnic
Society of Leipsic. It is as follows : Clean the bare portion of the
glass by rubbing it gently with fine cotton, taking care to remove every
trace of dust and grease. If this cleaning be not done very carefully,
defects will appear around the place repaired. With the point of a
knife cut upon the back of another looking-glass, around a portion of
the silvering of the required form, but a little larger. Upon it place a
small drop of mercury : a drop the size of a pin's head will be sufficient
for a surface equal to the size of the nail. The mercury spreads imme-
diately, penetrates the amalgam to where it was cut off with the knife,
and the required piece may now be lifted and removed to the place to
be repaired. This is the most difficult part of the operation. Then
press lightly the renewed portion with cotton : it hardens almost inmae-
3

26 ANNUAL OF SCIENTIFIC DISCOVERY.

diately, and the glass presents the same appearance as a new one.
Builder.

CEMENT FOR ROOMS.

A recent invention by M. Sorel, of Paris, is described to consist in
the discovery of a property possessed by oxychloride of zinc, which
renders it superior to the plaster of Paris for coating the walls of rooms.
It is applied in the following manner: A coat of oxide of zinc mixed
with size, made up like a wash, is first laid on the wall, ceiling, or
wainscot, and over that a coat of chloride of zinc applied, being pre-
pared in the same way as the first wash. The oxide and chloride
effect an immediate combination, and form a kind of cement, smooth
and polished as glass, and possessing the advantages of oil paint, with-
out its disadvantages of smell.

WIRE LATHING FOR WELLS.

W. E. Gedge, of London, England, has secured a patent for the em-
ployment of iron wires as a substitute for wood laths used on the walls
of rooms that require plastering. The wires are stretched and crossed
on the studs and joists and then secured in screw rings. The wires are
fixed at such a distance apart that the priming coat of thick plaster
mixed with hair will adhere to them perfectly. These wires do not
shrink nor warp like laths, and on this account they are said to be su-
perior for plastered walls.

PREVENTION OF FIRE ACCIDENTS.

An English architect proposes to construct buildings in an improved
manner by economizing the space which the staircases usually occupy,
and to render them fire-proof by dividing or insulating the staircases
from the building of which they form part. This he proposes to ac-
complish by arranging the stairs (which are to be made of incombusti-
ble materials), in a recess formed in the outer wall of a building ; which
recess is to extend from the foundation to the roof, and have no open-
ing whatever on its inner side ; but it is to be provided, where neces-
sary, with openings or doorways on its outer face, leading to balconies
(which are also to be formed of incombustible materials) fixed at the
level of, and giving access to, each of the floors or flats of the building.
By means of this arrangement of staircase and balconies, each floor will
be rendered totally distinct from, and independent of, that one below
or above it, so far as regards any internal communication therewith or
therefrom.

WATER-PROOF WALKS.

The following new method of path-making is recommended by the
London Gardener's Magazine, for its excellence, permanence, and
economy. Instead of making the walk of loose material, on the old
fashion, concreting is resorted to, by which the appearance of gravel is
retained with all its freshness and beauty of contrast to grass and flow-
ers, and the walk itself is rendered as dry and durable as the best
pavement. The modus operaudi is as follows : Procure a sufficient
quantity of the best Portland cement; then," with the help of a laborer,
turn up the path with a pick, and have all the old gravel screened, so

MECHANICS AND USEFUL ARTS. 27

as to separate the loam and surface weeds from it, and to every six
parts of the gravel add three parts of gritty sand of any kind, but
soft pit sand is unsuitable, and one part, by measure, of Portland
cement. When these are well mixed together in a dry state, add suffi-
cient water to make the whole into a moderately stiff working consist-
ence, and lay it down quickly two inches thick on a hard bottom. A
common spade is the best tool with which to spread it ; it must be at
once spread, as it is to remain forever, and a slight convexity given to
the surface. In forty-eight hours it becomes as hard as a rock ; not a
drop of rain will go through it, and if a drop lodges on it, blame your-
self for not having made the surface even ; but a moderate fall is suffi-
cient with such an impenetrable material. Not a weed will ever grow
on a path so formed ; not a worm will ever work through it ; a birch
broom will keep the surface clean and bright, and of course it never
requires rolling. It is necessary to be very particular as to the quality
of the cement. For the flooring of a green-house, fowl-house, or barn,
this is the best and cheapest that can be had, always clean, hard,
and dry, and never requiring repairs of any kind if carefully put down
in the first instance.

HOW MUSKET BARRELS ARE STRAIGHTENED.

A curious and interesting part of the operation of manufacturing
muskets is the straightening of the barrel. This straightening takes
place continually in every stage of the work, from the time the barrel
first emerges from the chaotic mass produced by heating the scalp,
until it reaches the assembling-room, where the various parts of the
musket are put together. As you enter the boring and turning rooms
of the Springfield armory, you are struck with surprise at observing
hundreds of workmen standing with musket-barrels in their hands,
one end held up to their eyes, and the other pointing to some one of
the innumerable windows of the apartment. Watching them a few
moments, however, you will observe, that, after looking through the
barrel for half a minute, and turning it around in their fingers, they
lay it down upon a small anvil standing at their side, and strike upon
it a gentle blow with a hammer, and then raise it again to the eye.
This is the process of straightening.

In former times, a very slender line, a hair or some similiar substance,
was passed through the barrel. This line was then drawn tight, and
the workman, looking through, turned the barrel round so as to bring
the line into coincidence successively with every portion of the inner
surface. If there existed any concavity in any part of this surface,
the line would show it by the distance which would there appear be-
tween the line itself and its reflection in the metal. This method has
not, however, been in use for over thirty years. It gave place to a
system which, with a slight modification, is still in practice. This
method consisted in placing a small mirror upon the floor near the
anvil of the straightener, which reflected a diagonal line drawn across
a pane of glass in a window. The workman then placed the barrel of
the musket upon a rest in such a position that the reflected line in the
mirror could be again reflected, through the bare of the barrel, to his
eye, the inner surface of the barrel being in a brilliantly polished
condition from the boring. When the barrel is placed at the proper

28 ANNUAL OF SCIENTIFIC DISCOVERY.

angle, which practice enables the person performing this duty to ac-
complish at once, there are two parallel shadows thrown upon opposite
side-s of the inner surface, which, by another deflection, can be made to
come to a point at the lower end. The appearance which these
shadows assume determines the question whether the barrel is straight
or not, and if not, where it requires straightening. Although this
method is so easy and plain to the experienced workman, to the un-
initiated it is perfectly incomprehensible, the bore of the barrel
presenting to his eye only a succession of concentric rings, forming a
spectacle of dazzling brilliancy, and leaving the reflected line in as
profound a mystery after the observation as before.

At present, the mirror is discarded, and the workman holds the
barrel up directly to the pane of glass, which is furnished with a
transparent slate, having two parallel lines drawn across it. The only
purpose subserved by the mirror was that of rendering the operation
of holding the barrel less tiresome, it being easier to keep the end of
the musket presented to the line pointing downwards than upwards.
Formerly this means of detecting the faults, or want of straightness in
the barrel, was the secret of one man, and he would impart it to no
one for love or money. He was watched with the most intense
interest, but no clue could be obtained to his secret. They gazed into
the barrel for hours, but what he saw they could not see. Finally,
some fortunate individual stumbled upon the wonderful secret, dis-
covered the marvellous lines, and ever since it has been common
property in the shop. Atlantic Monthly.

SMITH'S AIR-LIGHT.

A highly successful and economical application of the oxy-hy-
drogen lime light has recently been made by Dr. G. H. Smith, of
Rochester, New York ; atmospheric air being substituted in the place
of oxygen gas, and carburetted hydrogen, or common gas, in the place
of hydrogen. The rendering of these substitutes applicable for the
production of the oxy-hydrogen light a project which at first seems
chimerical is explained by the inventor as follows: "Common air
contains one part of oxygen and about three parts of nitrogen gas ;
hence it would require four parts of air to give the amount of oxygen
required for illuminating purposes ; i. e. to obtain one part of oxygen
four feet of air would be needed, as three feet would be nitrogen.
Now, the great difficulty in using air as a substitute for pure oxygen,
in the production of the lime light, is due to the fact (and to this
solely) that when four parts of air are combined with one of common
gas, the gas is so greatly diluted as to prevent its burning readily, and,
what is still worse, if combustion was complete, the nitrogen, not being
combustible, would fly off unconsumed, and carry away the heat gen-
erated to such a decree as to render the luminosity of the cylinder of

^J V /

lime (against which the ignited jets of the combined gases are direct-
ed) of no practical value. But if an amount of heat, from any source,
is applied to the current of air previous to ignition, sufficient to supply
the loss of heat abstracted by the inert nitrogen, at the time of com-
bustion, no heat is lost upon the lime, and the whole power of the oxy-
gen is obtained as though no nitrogen was present. Hence, by sup-
plying a current of preheated air to one of common gas ignited, an

MECHANICS AND USEFUL ARTS. 29

ample supply of oxygen is afforded, and all the heat generated is
saved and concentrated upon the lime." Herein is the principal feature
of Dr. Smith's invention. The invention is practically carried out for
railway (locomotive) lights the purpose for which it has thus far
been applied as follows : The burner is composed of four compound
jet tubes encircling a small cylinder of lime. A current of atmos-
pheric air, and one of coal-gas, is conveyed to each jet, and the two
allowed to mingle after leaving their respective jet orifices. The tube
conveying the stream of air, passes over several small gas burners,
which heat the air-tube to a high degree of heat, at a point near the
orifice of the tube, and by this device, the air current is intensely
heated before it reaches the jet and mingles with the jet of coal-gas.
The effect is, to produce the dazzling whiteness of the lime, peculiar
to the oxy-hydrogen light. When placed in the focus of a parabolic
reflector, such as are in present use upon locomotive engines, it is in-
creased to a ball of light twenty inches in diameter, or to the size of
the mirror. The flow of air and gas is reliably and simply controlled
by durable regulators and stop-cocks, within the lamp. Two gas-
holders containing air and coal-gas, respectively, under pressure, placed
under the engine, and communicating with the lamp by a small pipe
for each, carry twice or three times the requirements of a trip. These
receive their charge at the engine-houses, before starting, from two
stationary holders of larger dimensions, which are kept filled by a
small pump driven by the local power employed at those places. To
fill the holders on each locomotive occupies its engineer only from,
three to four minutes very much less time than is required for filling
and trimming an oil lamp.

This light has within the past year been introduced upon the loco-
motive engines of the New York Central Railroad, and its efficacy
and great economy has been so fully demonstrated that the invention
may without doubt be ranked among the most useful and novel of the
year.

IMPROVEMENTS IN TYPE-SETTING.

Mr. Thomas Rooker has lately introduced into the Tribune office, N.
Y., type-cases with movable bottoms. In these cases, the bottoms may
always be kept conveniently full in composition, and in distribution
the bottoms may be lowered so as to receive a large quantity of type.
Mr. J. H. Tobitt, of New York, and Mr. A. H. Bailey, of Boston, have
also recently interested themselves, to introduce composite type, or the
plan of uniting two or more letters upon one body, so that by one lift
two or three letters are set up instead of one. Mr. Bailey's system of com-
binations is calculated to save from twenty to forty per cent, in com-
position. When it is considered that the word the forms six per cent,
of the language, and and about four, while many others exceed about
two per cent, the advantage of a combination system is evident. The
difficulty in the matter is as to how many and what combinations may
be used with profit.

SCENE PAINTING.

M. Foucault proposes to remedy certain defects in scenic arrange-
ments by the following means. At present, our mountains, towns, and
3*

30 ANNUAL OF SCIENTIFIC DISCOVERY.

villages are of one piece with the back-scene ; and while nature pre-
sents objects to us through a cone of visual rays drawn from the eye,
the stage represents them in an exactly inverted position that is, Ave
see them through the base, instead of through the vertex of the cone.
By M. Foucault's ingenious and artistical plan, all these inconvenien-
ce's are obviated. The sky being so often required, 'he has made the
upper part of it fixed, of a dome-like shape, as in nature ; the lower
or perpendicular part is of canvas stretched on frames, and arranged
cylindrically, so as to form a panorama, the end of which cannot be
perceived from any point of the house. His mountains or towns of the
background are independent of the sky, and stand forth in real relief;
so do his trees or shrubs, which are made to rise from or descend below
the floor. As for those objects which are nearer the foreground, they
are made of two pieces, the lower one to sink down, the upper one, a
fly, to be drawn upward when a change of scene is required. His
views of the sea or of interminable plains display a vast expanse never
yet seen on a stage ; rich architecture is also cut out, and shows beau-
tifully on the fixed sky of the background, which, however, is so con-
trived that all the phenomena of storms, sunset, approaching night,
travelling clouds, with varying illuminations, etc., are imitated with
surprising fidelity.

SQUARING THE CIRCLE.

M. Hobinet has presented to the French Academy aperies of equa-
tions laboriously worked out and represented as having a remarkable
approximation to accuracy. The proportion of various multiples and
fractions of the diameter to the circumference is given, and it is stated
that " the side of a square equivalent to a circle of a diameter equal to
unity = Iff 0.000,0006 = 0.8862269."

A NEW SLOPE-LEVEL, BY M. RIBOT.

This instrument is designed to solve practically either of the follow-
ing inverse problems, namely, to find the slope per metre of a given line ;
or, to set a line to a given slope per metre (or per yard). The instru-
ment is so simple as scarcely to need description. The horizontal dis-
tance between the feet or points of support is exactly one metre (or
yard). The right hand foot of the figure is capable of protrusion by
a screw, and is provided with a scale to measure the amount of this
protrusion. When the two feet are on a level, the index is at the
zero of the scale. If you want to determine a given slope, project
the foot until the instrument stands on the slope ; the protrusion mea-
sured on the scale gives the slope in terms of the distance apart of the
feet (metres or yards). If you want to establish a given slope, set the
foot to the indicated point of the scale, and adjust your plane to the
instrument. The lower bar of the instrument may be graduated so
that the plummet shall read* angles of slope. Dull. Soc. d' Encour.
pour V Indus. Nationale.

A NEW MODE OF CONSTRUCTING CASKS.

A new method of constructing casks has been recently patented by
John Connolly, of Boston. It consists in making the heads of the cask
of iron, or other metal, so arranged that the iron head serves at once

MECHANICS AND USEFUL ARTS. 31

as a head, a cap for oozing staves, and as a head-hoop, all combined in
one. The head may be screwed on, the flanch or hoop part of the
head having a female screw cut on it which cuts a worm for itself,
and embeds in the stave as it goes on ; or it may be barbed with con-
centric rings, and driven on with a hammer. This latter method, the
patentee considers as generally preferable. The advantages of this
improvement for preventing leakage and furthering the durability of
the casks are considered to be very great.

Mr. Connolly also recommends the construction of casks of iron in
the place of wood, with heads applied in accordance with his improve-
ment. The body of the cask might be rolled out in one piece, or it
might be of two, three, or more pieces, which, being ground at joints,
or rebated, or tongued and grooved and put together in any way with
packing, would insure a tight joint, if well bound, as at present, with
hoops. A cask so constructed, of boiler-iron, could be more readily
" shooked " and " set up " than a wooden one. If dented, it could be
beaten out. No more shrinkage, with its consequent leakage and
labor, would then occur. Such casks would last for generations.

A NEW BRICK AND MORTAR ELEVATOR.

There is no operation in all the arts in which the waste of labor is
more palpable than that of carrying up brick and mortar in erecting
buildings. In order to raise forty or fifty pounds, the hod-carrier is
required to exert muscular effort to raise his own weight (some one
hundred and fifty pounds) in addition, thus involving a waste of about
three-fourths of the power expended. An invention to economize the
power required in this operation, devised by Mr. T. F. Christman, of
Wilson, North Carolina, is substantially as follows : An endless chain,
formed of iron links, passes around two pulleys, one at the ground,
and the other at the top of the wall. The pulleys have spurs which
take into holes in. the belt, to prevent slipping, and the upper pulley
is furnished with a crank for turning it. Hoppers are secured upon
the upper side of the belt for receiving the brick, and as the wall rises,
the belt is lengthened bv the insertion of additional links, which are

/

furnished with hooks so that this may be readily done. Scientific
American.

NEW MATERIAL APPLIED TO THE ARTS.

At the great London Exhibition, 1862, a new material applied to
the manufacture of fancy articles, such as picture-frames, canes, inlaid-
work, &c., attracted considerable attention. It is obtained from sev-
eral species of marine plants, washed up on the shores in the vicinity
of the Cape of Good Hope, South Africa, but principally from the
lamlnaria buccinalis. It is of a dark color, and when fresh, it is thick
and fleshy, but when it is dried it becomes compact and its surface
looks like a beautifully-grained deer's horn. After it becomes dry
and hard it can be rendered soft again by steeping in water, and in
this condition it may be stretched and formed into various shapes.
When dry it can also be reduced to powder, then made plastic by
soaking in water, and in this condition it may be struck into almost
any shape in a die press. It comes out of the moulds like articles
formed of gutta percha. The discoverer of the use of this substance

32 ANNUAL OF SCIENTIFIC DISCOVERY.

prepares the plant by cleaning it first with weak caustic alkali, and
then with dilute sulphuric acid, after which it is washed, and before it
is quite dry it may be pressed into sheets or any other form. It then
may be rendered very hard by steeping it in a hot solution of
alum, after which it is removed to a hot room where it is dried, and
retains its shape afterward. Reduced to powder it may also be
mixed with various substances, like india rubber, and moulded into a
great variety of articles. When it is bleached, by treating it first with
a- warm alkaline solution, and afterward with sulphurous acid gas, it
resembles ivory and may be used as a substitute for that material.

MANUFACTURE OF STRINGS FOR MUSICAL INSTRUMENTS,
AND OTHER USES, OF GUT AND SINEW.

The London Mechanics' Magazine publishes the following interest-
ing article on the above subject :

A manufacture, of which comparatively little is known, is the pre-
paration of the substance usually termed catgut, though for the most
part made from the dried, twisted, peritoneal coverings of the intes-
tines of sheep. Catgut cord is used for a variety of purposes where
strength and tension are required, as for the strings of musical instru-
ments, for suspending clock-weights, bow-strings for hatters' use, and
for archers' bows.

The manufacture of musical strings requires a great amount of care
and skill, both in the choice of materials and in the manufacturing
processes, in order to obtain strings combining the two qualities of re-
sistance to a given tension and sonority. Until the beginning of the
last century, Italy had the entire monopoly of this trade, and they
were imported under the names of harplings, catlings, lute-strings,
&c. ; but the trade is now carried out, with more or less success, in
every part of Europe. However, in the opinion of musicians, Naples
still maintains the reputation of making the best small violin strings,
because the Italian sheep, from their leanness, afford the most suitable
material ; it being a well ascertained fact, that the membranes of lean
animals are much tougher than those of high condition. The smallest
violin strings are formed by the union of three guts of a lamb (not
over one year old), spun together.

The chief difficulty in this manufacture is in finding guts having
the qualities before mentioned, namely, to resist tension, and giving
also good vibrating sounds. It is far more easy to arrive at the proper
point in the making of harp, double-bass, and other musical strings, and
the manufacturer is not so much circumscribed in the choice of the
proper material. The tension upon the smallest string of the violin,
which is made of only three guts, is nearly double that on the second
string, formed by the reunion of six guts of the same size.

In the preparation, the sheep's guts, well washed and scoured, are
steeped in a weak solution of carbonate of potash, and then scraped
by means of a reed cut into the shape of a knife. This operation is
repeated twice a day, and during three or four days, the guts being
every time put into a fresh solution of carbonate of potash, prepared
to the proper strength. In order to have good musical strings, it is
indispensable to avoid putrid fermentation ; and as soon as the gutg

MECHANICS AND USEFUL ARTS.

rise to the. surface of the water, and bubbles of gas begin to be evolved
from them, they are immediately spun.

In spinning, the guts are chosen according to their size ; combined
with throe or more, according to the volume of the string required,
they are fastened upon a frame, and then alternately put in connexion
with the spinning-wheel, and submitted to the required torsion. This
operation performed, the strings, left upon the frame, are exposed for
some hours to the vapor of sulphur, rubbed with a horse-hair glove,
submitted to a new torsion, sulphured again, further rubbed, and
dried.

The dried strings, rolled upon a cylinder and tied, are rubbed with
fine olive oil, to which one per cent, of laurel oil has been previously
added. The oil of laurel is supposed to keep the olive oil from be-
coming rancid.

The gut-strings employed by turners, grinders, and for cleaning
cotton, &c., are made with the intestines of oxen, horses, and other
animals. These, cleared by putrefaction of the mucous and peritoneal
membranes, and treated by a solution of carbonate of potash, are cut
into straps by means of a peculiar knife, and spun in the same way as
the musical strings. The uses of bladders and gut for holding lard,
for covering gallipots and jars with preserves, as cases for sausages,
polonies, &c., and other domestic purposes, are well known. Lately,
however, the vegetable parchment, as it is termed (which is ordinary
paper steeped in sulphuric acid), has come into extensive use for this
purpose.

Insufflated, or inflated guts, are chiefly employed for the preserva-
tion of alimentary food. They have to pass through a long series of
modifications and processes, before becoming fit for use. The end of
these preparations is, to free the muscular membrane of the intestine
from the two other membranes covering it, the peritoneal and the
mucous.

The first operation of scouring consists in freeing, by means of a
knife, the gut from the grease attached to it, and also of the greatest
part of the peritoneal membrane. The scoured guts are washed and
turned inside out, then tied together, put into a vat without any more
water than that adhering to them, and left in this state to undergo a
putrid fermentation. The time required for this operation will be from
five to eight days in winter, and two or three days only in summer.
If the fermentation were pushed too far, the guts would be disorgan-
ized : to avoid this inconvenience, the workmen are often obliged to
add some vinegar, in order to neutralize the ammoniacal compounds
formed, and also because fermentation is slow in the presence of acids.
After this fermentation, the mucous membrane is completely decom-
posed, and the remaining portions of the peritoneal membrane are
easily taken off. The guts are then well washed, and insufflated (in-
flated).

This operation is performed in the same way as swelling a bladder,
with this difference, that the extremity of the gut is tied by a ligature,
serving also to join a new gut insufflated (inflated) in the same way.
During this operation, the guts exhale the most noxious smell, and
workmen employed at such work could not blow or insufflate many
days in succession without having their health affected.

34 ANNUAL OP SCIENTIFIC DISCOVERY.

In order to prevent that inconvenient, unhealthy process of manu-
facture, the Sociele d' Encouragement of Paris proposed a premium
for a chemical process enabling the manufacturers of these articles to
dispense with putrid fermentation. The process suggested by Mons.
Labarraque, the successful candidate, is remarkable for its cheapness
and the facility of its application. In following the method recom-
mended by this chemist, these animal matters can be worked more
easily, and kept for a longer time without evolving any noxious
smell.

The guts, previously scoured, are put into a vat containing, for
every forty guts, four gallons of water, to which 1^ pounds oxychloride
of sodium, marking 13 on the areometer of Beaunie, is added. After
twelve hours of maceration, the mucous membrane is easily detached,
and the guts are free from any bad smell ; by this method, the process
of insufflation is more easily performed.

The insufflated guts are suspended in a dry room until the desicca-
tion is complete ; and, once dried, the extremities by which they were
tied together are cut, and, in pressing the hand over the length of the
insufflated (inflated) gut, the air inside is completely, taken out. The
guts are then submitted to fumigation by sulphur, in order to bleach
and to preserve them from the attacks of insects. After this last opera-
tion, the guts are fit for use.

Besides a large home supply of bladders, England imports several
hundred thousand a year, packed in salt and pickle, from America and
the Continent ; and the aggregate value of the bladders used in Great
Britain, is stated at 40,000 or 50,000.

NEW METHOD OF PREPARING GUNPOWDER.

Mr. W. Bennett, of England, has invented a new method of manu-
facturing gunpowder, the ingredients consisting of lime, nitre, sulphur,
and charcoal ; the lime is dissolved in a sufficient quantity of water
to bring the other elements into a paste. The lime, after having
been made into a solution, is strained through a fine sieve ; this solu-
tion is then added to the other ingredients, and the whole is put into
a mill, and ground until it becomes a paste ; it is then taken out of the
mill, and passed between two rollers, one grooved and the other plain.
The paste, by passing between the rollers, is formed into long strips of
a triangular shape ; it is then carried on an endless web or canvas
over some hot tubes, which are heated by steam, hot waier, or any
other artificial heat which may be applied ; by this means, the strips
are easily broken into grains. This mode of manufacture prevents a
great deal of danger, as the powder is pulverized and brought into
grain while in a wet state. The lime makes a firm grain, resists the
damp, and gives it a degree of lightness which increases the bulk 25
per cent, over ordinary gunpowder, a great advantage for blasting
purposes. Plaster of Paris, Koman or Portland cement, or other strong
cementing substance, may be used as a substitute for lime. And the
patentee finds that for blasting purposes the following proportions an-
swer well, that is to say, nitre, 65 Ibs. ; charcoal, 18 Ibs.; sulphur, 10
Ibs. ; and lime, 7 Ibs. ; but the proportions may be varied according to
the strength required.

MECHANICS AND USEFUL AETS. 35

THE CONSTRUCTION OF SAFES.

The following is an abstract of a series of highly interesting and im-
portant researches recently made by Prof. E. N. Horsford, of Cam-
bridge, Mass., on the " Construction of Safes," intended for protection
against fire, dampness, rust, and frost:

Protection against Fire. The experience of the last few years has
practically demonstrated, what might have been foreseen, that protec-
tion against fire can be relative only, not absolute. Fire-proof buildings,
so called, yield, when stored with combustible materials and for a long
time surrounded by flame. The best of fire-proof safes are destroyed,
when exposed to heat sufficiently intense and prolonged. This being
admitted, how shall the largest practical measure of protection against
fire be secured? First. By placing the books, papers, etc., to be pre-
served, in an incombustible enclosure, as of iron. Second. By sur-
rounding the books, etc., by a non-conductor of heat. Third, and
chiefly, by interposing between the incombustible enclosure, or outer
iron shell, and the wooden case containing the valuables, a substance
w r hich on the approach of fire, is converted into vapor, absorbing the
heat and carrying it. away.

If the second and third be omitted, the contents of the safe will* be
destroyed as soon as the iron enclosure has become sufficiently hot to
set them on fire. If the third only has been omitted, the power of
preservation will be proportioned to the thickness of the layer of non-
conducting material ; and this, at the best, is relatively but for a' brief
period. If the second, only, has been omitted, since the protection
arising from vaporization is due to the absorption of heat in convert-
ing liquid or Solid substances into vapor, it will obviously be propor-
tioned to the quantity of substance so converted into vapor. A hun-
dred pounds of water will absorb twice as much heat in passing off in
the form of steam, as fifty pounds will ; and a safe that contains one
hundred pounds of water to be evaporated, will preserve its contents
in safety, through a fire in which a safe containing but fifty pounds
would be destroyed. A safe will then, manifestly, be a better protec-
tion against fire, in proportion as it unites within it, an incombustible
shell, the best non-conductor, with the largest amount of liquid or solid
to be converted into vapor, at a temperature not dangerous to the con-
tents of the safe.

Dampness. Injuries from dampness in safes are not unfrequently
of a most serious character ; such as the mildew, and disintegration of pa-
pers, writings, &c. These injuries arise from the transmission of water
irom the fire-resisting composition, through cracks imperfectly closed
at the time of manufacture, or made subsequently by rusting; or
through the pores of the wooden case ; or by the freezing of the water of
the composition, by the expansion of which the walls are separated from
each other, and communication established between the filling and the
chamber of the safe. They may be prevented by so constructing
the safe as absolutely to prevent any communication of water or
vapor between the filling of the safe and the books and papers.

In a climate like ours, a safe may be exposed occasionally to tem-
peratures below freezing. Any of the safes, as at present constructed,
cannot contain any considerable quantity of water above that in chem-

36 ANNUAL OF SCIENTIFIC DISCOVERY.

ical combination, without the danger of bursting by cold. This open-
ing of the seams of the safe at once exposes the contents of the case
to the exhalation of moisture from the filling. The protection against
this kind of injury manifestly lies in such construction of the safe as
will provide for the expansion consequent on freezing, without opening
the joints or seams of the various parts.

Rust. This is one of the agencies by which communication be-
tween the filling and the chamber of the safe is effected after the lapse
of time ; and by which the contents of the chamber become damp.
It may be prevented by consuming the oxygen of the air which would
otherwise act on the iron. Chemical compositions are prepared which
will, by absorbing the oxygen, perfectly protect the iron from corrosion
or rust, even in the presence of air and water.

Varieties of Safes in use. The safes at present in use differ from
each other in various respects, but chiefly in the capacity of the com-
position employed, to yield vapor.

The earliest safes were designed chiefly to protect treasure against
burglary, and were distinguished for their strength. Next came safes
having non-conducting walls as protection against fire. In 1840, a
safe appeared which took advantage of the principle of vaporization of
water as protection against fire. The alum safe, upon the same prin-
ciple was devised in 1843. The gypsum safe, also on the same princi-
ple, has long been in use. The cement safe, in which hydraulic cem-
ent is substituted for gypsum, has been many years in use. In the
English safe of Milner, invented in 1840, the space between the
iron shell and wooden case is occupied with closed tubes containing
water, these tubes being imbedded in saw dust. On exposure to fire,
the tubes burst, and the water, flowing into the sawdust, is converted
into vapor, and escapes through the joints of the iron shell.

In the alum safe, invented by Messrs. Tann, of England, and a
modification of which is produced in this country, the vapor is derived
from the water of crystallization of the alum. Twenty per cent, of the
weight of the alum is converted into vapor at 212, and eighteen more
at 250. The remainder is given up only at a heat destructive to the
contents of the safe.

In the ordinary gypsum safes, the surplus water added in the mixing,
if it does not remain to do injury by charging the case and books with
dampness, or by freezing, is in process of time exhaled until there re-
mains only what has entered into chemical combination. This latter
amounts to twenty per cent. Of this, ten per cent, is given up at 212,
and half of the remainder below 300. The cement safes, as they are
usually prepared, contain, after setting, and after time for giving up
the surplus water, about six per cent, of water. Of this, one per cent.
goes out at 212. As the Alum safes are prepared in this country, the
alum is mixed with pipe clay, and this mixture with fragments of brick,
the former to absorb the water as the alum melts and to facilitate the
vaporization ; the latter to give support and prevent the composition
from falling when the alum melts. The proportion of alum is about
one quarter of the whole. This would give of water from the compo-
sition, at 212, only five per cent, and at 250, four and a half per
cent, more, or only nine and a half in all. If the alum were raised to
the proportion of one half of the whole mixture, it would give up but

MECHANICS AND USEFUL ARTS. 37

ten per cent, of water at 212, and nine more at 250, or only nineteen
per cent, at temperatures not dangerous to the contents of the safe.

In most fires the exposure is for so brief a period that the protection
in some of the best safes is adequate ; but there is the constant possi-
bility that the fire may be too powerful and too protracted for the com-
position employed, and the protection consequently inadequate.

Can this protection against fires be increased ? The incombustible
inclosure is of wrought iron, and nothing could be better than this.
The points, therefore, remaining for consideration are, What is the
best practicable non-conductor ? and, What is the best composition for
keeping down heat for vaporization ?

In answer to the first question, experiments were made, among other
materials, with Infusorial Earth ; a mixture of Sal Soda and Gypsum ;
a mixture of Glaubers Salt and Gypsum; set Cement; Alum and dry
Cement ; Gypsum with Gelatine.

A wrought-iron cup, containing about eight ounces of water, was filled
with each substance in its turn, and the bulb of a thermometer imbed-
ded to the same distance from the bottom in all. The vessel and its
contents were then subjected to the same degree of heat. The con-
ducting power, or the facility of heating throughout, was measured by the
number of degrees swept over by the ascending column of mercury in
successive minutes. The range of heat was from 220 to 572.

Infusorial earth was heated 27 in one minute.

Sal soda and gypsum taken in equal parts, 14 in one minute.,

Glaubers salt and gypsum, taken in equal parts, 12 in one minute.

Cement, set and dried, 11 in one minute.

Potash alum, 3 oz. ) 5 per minute, from 220 to 300.

Dry cement, 6 oz. ) 4 per minute, from 300 to 572.

Gypsum, 6 oz., and water, 6 oz., | 2 per min. from 220 to 300.
with 3 per cent, of gelatine, ) 4 per min. from 300 to 572.

From each, the water due to a temperature of 212, had, as already
intimated, been driven out. In the cement, alum, and gypsum, there
remained water in combination. The infusorial earth proved the best
conductor, and would of course be the poorest substance for filling a
safe. Of all, the gypsum and gelatine, as prepared for this experiment,
.throughout the range in which the contents of the safe are secure
against fire, namely, below 300, affords the best protection, so far as
conduction is concerned. It is, indeed, difficult to conceive of a sub-
stance better suited for non-conduction than this mass of set plaster and
gelatine, after the surplus water alternating with every particle of gyp-
sum has been driven out, leaving behind an infinity of minute cavities,
rendering the whole porous and non-conducting to the last degree.

How shall this quality be combined most advantageously with the
second requisite mentioned above, that of supplying matter to be va-
porized, thereby carrying the heat away ?

Two sets of experiments were undertaken to determine this point.
The first on a small scale, the second on a large and more practical
scale. The first was conducted at the same time with the series al-
ready detailed, and employing the same apparatus. The wrought-iron
cup was filled with each mixture in turn, supported at a constant alti-
tude over a flame of uniform height, and the thermometer imbedded to
the same depth in all.

4

38 ANNUAL OF SCIENTIFIC DISCOVERY.

The results showed, that, as regards protection to be afforded by
vaporization from 212 to 220, the following substances ranked in
value in the order stated : Gypsum, gelatine, and water; Cement;
Glaubers salt and gypsum ; Sal soda and gypsum ; Alum.

The question of using a composition which should give up vapor at a
temperature above 212 only, was tested in the use of a mixture of
sulphate of ammonia and common salt, diluted with powdered coke,
which, on the application of heat, yielded sal ammoniac. Experiments
were also made with a mixture of ammonia-alum and common salt, dilu-
ted, like the above, with coke. This yielded water in addition to sal
ammoniac. Clay and powdered brick were substituted for coke. They
gave results inferior to all except the potash-alum.

In addition to these laboratory experiments, a series were undertaken
on a scale of such magnitude as to render the results of more direct
practical value. As the object was to determine the relative excellence
of different kinds of safes in which all the circumstances of exposure
were the same, it was conducted with great attention to details, and
was, on many accounts, the most important ever made of which any
record, has been preserved.

Experiments in Reverberalory Furnaces. Five wrought-iron safes were
constructed, each of one cubic foot capacity. For each, a small wooden
box four inches in the clear, and three-quarters of an inch in thickness,
was prepared to represent the inside case. When in place, there was
a space for composition of three inches thickness on every side of the
box. In each wooden box was placed a piece of parchment, some
white writing paper, cotton batting, a piece of sealing-wax, a self-
registering thermometer ranging to 600, and a series of small ther-
mometers bursting at given temperatures.

No. 1 contained sulphate of ammonia, 15.5 Ibs. ; common salt, 15.5
Ibs. ; powdered coke, 24 Ibs.; wooden box, 2 Ibs.; iron shell, 27 Ibs.
Total, 84 Ibs.

No. 2 contained potash-alum, 26 Ibs. ; pipe-clay, 26 Ibs. ; brick, 28 f
Ibs. ; dry cement, to fill, f Ibs. ; wooden box, 2 Ibs. ; iron shell, 28 f Ibs.
Total, 11 2^ Ibs.

No. 3 contained ammonia-alum, 26 Ibs. ; common salt, 13^ Ibs. ;
coke, 16 Ibs. ; wooden box 2^ Ibs. ; iron shell, 29^ Ibs. Total, 87^ Ibs.
No. 4 contained cement, 60 Ibs. ; water, 19|- Ibs. ; soapstone front, 9
Ibs. ; wooden box, 2 Ibs. ; iron shell, 30 Ibs. Total, 120| Ibs.

No. 5 contained plaster of Paris, 50 Ibs.; water, 21 Ibs. ; dry cement,
to fill, 9 Ibs. ; wooden box, 2 Ibs. ; iron shell, 28 Ibs. Total, 110 Ibs.

These safes were carefully introduced into a reverberatory furnace
from which a discharge of twenty thousand pounds of molten iron had
just taken place, and when the walls were nearly at the temperature
of melted iron. The safes were placed on the bottom of the furnace,
the door closed, and after adjusting the draft so as to permit the fur-
nace to cool slowly down in the usual way, the safes were left from five
o'clock in the afternoon till ten the next morning.

On taking the safes from the furnace, they were first weighed. No.
1 had lost 8j Ibs. ; No. 2, 1 15| ; No. 3, 2 16 ; No. 4, 13 ; No. 5, 16.

l This is the common alum safe, except that one-third of alum was employed
instead of one-quarter.

-' One pound of this, and of each of the preceding two, is due to the charring of
the wooden box.

MECHANICS AND USEFUL ARTS. 39

The temperature of No. 1 had been above 600. The paper, cotton
batting, and box were charred ; the parchment and sealing-wax were
destroyed.

The temperature of No. 2 had been as high as 580. The paper,
cotton, and box were charred. The parchment and sealing-wax were
destroyed.

The temperature of No. 3 had been 350. Contents were much
less injured than those of No. 1 and No. 2, but were still greatly dis-
colored. The box was partially charred.

The temperature of No. 4 was 287. The paper and cotton were
discolored. The box thoroughly dried and shrunken somewhat, but
not charred. The parchment was shrivelled and the sealing-wax
melted.

The temperature of No. 5 had been 212. The parchment was
somewhat shrivelled, and sealing-wax melted ; but the paper, cotton
batting, and box were uninjured.

In the safes filled with potash-alum, clay, and brick, with ammonia-
alum, salt and coke, and with sulphate of ammonia, salt, and coke, a
coarse porous wall around the interior wooden case was preserved after
the volatile matters had been driven out. In the cement safe, the cem-
ent retained about one-third of its water and the form perfectly. In
the gypsum and water safe, the plaster retained its form. It had parted
with about four-fifths of its water. (Strictly -||.)

From the foregoing, it is evident that in keeping the temperature
down a given time, 7 Ibs. of sal-ammoniac are inferior to 14| Ibs. of
water from potash-alum; and these inferior to 15 f Ibs. of water and
sal-ammoniac, from ammonia-alum and salt; and these inferior to 13
Ibs. of water from the cement safe; and these inferior to 16 Ibs. of
water from the plaster and water safe.

In the gypsum and water safe, 5 pounds of water were fixed in the
setting, and ]6 pounds were held by capillary attraction. These 16
were driven out at 212. There remained 5 in combination, at the
close of the experiment, to be driven out at the same temperature. In
the cement safe, G pounds were fixed in the setting, and 13f pounds
were held by capillary attraction. Of these 13f, 13 were driven out
at 212. There remained but f of a pound to be driven out at 212.

In the alum safe, there were but 8 Ibs. expelled at 212.

In summary the gypsum and water sate lost 16 Ibs. at 212 ; the
cement and water safe, 1 3 Ibs. ; the alum safe, 1 S Ibs.

The water remaining to be expelled, at 212, from the gypsum and
water safe, was 5 Ibs. ; from the cement safe, was f lb. ; from the alum
safe, was 0.

Not only was there no water to be driven out at 212, but 6| Ibs.
had been driven out at much higher temperatures, the last at 580.

A cement safe, as ordinarily made, set and dried, of these dimensions,
contains a little more than half a pound of water to be driven out at
212. In a plaster safe, set and dried, there would have been but 5
Ibs. to be driven out at 212. In an ordinary alum safe, there would
have been less than 8 ; while in the gypsum and water safe, as
here prepared, there were 21 Ibs., which, by the process already de-
scribed, might have been increased to 50 Ibs.

1 A part of this loss was evidently due to the moisture in the clay.

40 ANNUAL OF SCIENTIFIC DISCOVERT.

The potash-alum safe lost altogether within l Ibs. as much water as
the plaster and water safe, but nearly one-half went out at temper-
atures from 212 to 58*0, a range destructive to books and papers.
The ammonia-alum and salt safe lost about 20 per cent, more of water
and sal-ammoniac than the cement safe of water alone, and yet did
not afford the same degree of protection, for the cement safe was heated
only to 28 7 , 1 while the ammonia safe was heated to 350.

Experiment in a Furnace at a White Heat. Another experiment
was undertaken with four safes of the capacity of one cubic foot each.
Each contained a wooden box, enclosing a series of thermometers con-
structed to burst at given temperatures.

No. 1 contained cement, 64 Ibs. ; water, 3| Ibs. This is cement
containing the quantity of water which remains after the filling is set
and dried.

No. 2 contained plaster, 62| Ibs.; water, 12 Ibs. This is a plaster
of Paris safe, containing twenty-five per cent, more than the quantity
of water due to plaster set and dried.

No. 3 contained alum, 33 Ibs.; pipe-clay, 33 Ibs.; brick, 19 Ibs.
This safe, with a smaller proportion of alum, is in extensive use in this
country.

No. 4 contained plaster, 28 Ibs. ; gelatine, 2 1^ Ibs. ; water, 43 Ibs.

These safes were placed in the same reverberatory furnace in which
the preceding experiment was conducted. There was this difference
between the experiments : The first was conducted with a constantly
falling temperature. This with a temperature carried from freezing
up to a white heat, and there maintained for thirty minutes ; and then
permitted to cool down. At the end of the first half hour, Nos. 1 and
2, which were least exposed, were red hot ; No. 3 was at low red, and
No. 4 was dark.

At forty minutes, the condition was the same. At forty-two min-
utes, pronounced melting heat by the workmen, Nos. 1, 2 and 3 were
red, but 4 still dark equally. At fifty minutes, No. 4 became low red,
and No. 3 was burnt through and melted away at points nearest the
fire. At 60 minutes, No. 3 was at a white heat, and No. 4 was red.

This white heat was maintained for thirty minutes, when the furnace
was opened and cooled down sufficiently to examine the condition of
the safes.

No. 4 was burned so as to crack a little on one side, but was not
melted in any part. No. 3 was melted away from the top, front, and
two sides. The side farthest from the fire, and bottom, were alone
whole. No. 2 was scarcely less injured. The melting did not, how-
ever, extend so far down the sides. No. 1 , which was further from the
fire and sheltered by the other safes, was burned but not melted.

The fire was again raised to the melting point, the furnace closed,
and the safes left in this heated chamber, slowly cooling down, from five
o'clock in the afternoon till ten o'clock the next morning.

1 This elevated temperature, while there was still water in the cement, is mani-
festly due to the conducting' power of the soapstone upon which the wooden box
rested.

2 I employ the term gelatine as expressing in a single word the substance ob-
tained by the action of boiling water from gelatinizable substances, like sea-weed,
of the variety known as Iceland moss, or potato starch, or animal membranes,
or from other similar vegetable aiid animal substances.

MECHANICS AND USEFUL AETS. 41

On opening the furnace, the appearances of the safes had not appar-
ently changed since the examination at the close of the first experi-
ment. The wooden boxes in Nos. 1, 2, and 3, had been destroyed.
The temperature in No. 2 had been above 600, and in Nos. 1 and 3,
above 300, but not to 600, though probably not far below.

The wooden box in No. 4 was as fresh as when put in. The ther-
mometer bursting at 150 was destroyed, but that bursting at 212
was sound. The heat had not attained to that of boiling water. It
will be borne in mind that No. 1 is the ordinary cement safe, No. 2 is
the ordinary plaster of Paris safe, No. 3 is the alum safe, and No. 4
the new safe. The first three were destroyed, while the temperature
in No. 4 was, at the utmost, entirely within the range of safety to the
books and papers.

Conclusions. 1st. It is evident that the protection against fire is
mainly proportioned to the quantity of water the safe can give up to ~be
carried away as steam, and not to the non-conducting quality of its filling.

2d. It is evident, further, that the protection against fire is not
simply as the quantity of water that may be present in the composition
for filling, but as the quantity of water that may be parted with unre-
strained by chemical affinity, or WATER AS SUCH. The more powerful
the chemical affinity resisting the escape of vapor, the more elevated
must be the temperature at which it will leave, while the capacity of
the escaping vapor to render heat latent or to absorb and carry it
away will remain unchanged. The same quantity of water in combi-
nation in alum is not so serviceable in keeping down the temperature
as when free.

3d. It is evident, further, that while the water, in its uncombined
or natural state, must constitute a large part of the filling of a safe in
order to make its protection against fire in the highest degree avail-
able, this water must be held in solid form so as to give strength to the
safe ; and the safe must be so constructed as to prevent the water from
passing off by leakage or as vapor, to the injury of the books and pa-
pers, or to the lessening of the fire-proof qualities of the safe ; and yet
be so constructed as to allow, on the application of high heat, the most
free escape of vapor from those points to which the heat is applied,
without endangering the strength of the safe, or driving the vapor into
the interior chamber of the safe ; and withal so arranged as to permit
freezing, without injury to the safe or its contents.

In a safe made in the light of the foregoing experiments, from 70 to
80 per cent, of the space appropriated to filling was occupied by
water, and yet was exposed for a day and two nights to a temperature
of zero without injury.

On exposure to fire the water is resolved into vapor first at the outer
surface of the filling, and leaves the best non-conductor, according to
the results of foregoing experiments between the water which remains
and the heated metal of the exterior shell. At length, when all the
water has been driven out as vapor, there remains the non-conductor
of the whole thickness of the filling, to protect, as long as it may, the
contents of the case.

42 ANNUAL OF SCIENTIFIC DISCOVERY.

THE GREAT BOSTON ORGAN.

During the past year there has been erected in the Music Hall, of
the city of Boston, Massachusetts, an organ, which for absolute power
and compass ranks among the three or four mightiest instruments ever
built ; and in the perfection of all its parts, and in its whole arrange-
ments, challenges comparison with any the world can show. The in-
strument in question was built by E. F. Walcker, of Ludwigksburg,
in the kingdom of Wiirtemburg, and was upwards of six years in the
course of construction. Its cost was upwards of $50,000, and the case
alone cost $15,000.

In itself, this organ may be described as really comprising five dis-
tinct organs, or systems of pipes, which are capable of being played on
alone, or in connection with each other. Four of these are played
upon by manuals or hand key-boards, and the other by pedals or a
foot key-board. The lowest of the former controls the swell organ,
the pipes of which, as in other instruments, are enclosed in a box (in
this case, itself as large as many complete organs), and so arranged
that it may be open or perfectly tight at the will of the performer, thus
giving opportunity for light and shade in endless variety. This organ
contains 18 registers or stops, with which are drawn on or shut off an
equal number of ranks or series of pipes, all of which, or any of them
separately or in combination, may be made to speak through the swell
manual. Next above this is placed the key-board of the " great
organ," as it is technically called. Here we have 25 registers, all
of which connect with pipes on a large scale, and are the loudest
voiced pipes in the whole organ. Here are the grand diapasons which
form the foundation of the whole sound-superstructure, and the im-
mense trumpets and clarions which ring out like a call to battle. Above
the great organ manual comes that of the choir organ, which has 15
registers, and is in many respects the " great organ " on a softer scale,
but without the harsher reed stops. The last and upper manual be-
longs to the solo organ, which also answers for the echo organ, con-
taining 1 1 stops, and among them the famous vox humana, the quali-
ties of which have not yet been publicly tested. The pedals are the
only remaining key-board, and in connection with them are 20 dis-
tinct stops, 15 loud and the rest soft, some of the former being monster
reeds and a close imitation of orchestral instruments. We have then
a total of 89 speaking stops, which may all be combined, and a grand
total of 5474 pipes. The largest of these pipes measure thirty-two
feet in length, and are sufficiently capacious in diameter to allow men
to crawl through them, while the finest tubes " are too small for a baby's
whistle." The breath to the'se pipes, " to be poured forth in music, " is
furnished by twelve pairs of bellows, moved by water-power derived
from the Cochituate reservoirs.

But this great instrument does not differ from other organs merely
in size and wonderful variety of stops, but it excels them in almost
every detail which can be mentioned. The principal diapasons are
made of the purest English tin which is consistent with stability, and
the pipes in the swell organ, although they are always hidden from
view, are finished with the most scrupulous nicety. The dip of the
keys of ordinary organs is three-eighths, or at the most three-eighths

MECHANICS AND USEFUL ARTS. 43

and a sixteenth of an inch, while the keys of this organ dip no less than
five-eighths of an inch, presenting a considerable obstacle to players
unused to such great depth. But the difficulties which would arise
from such a vast "amount of mechanism connecting with the keys, ask-
ing of an organist's finger the strength of a blacksmith's arm, are over-
come by a delicate pneumatic action, which is called too easy rather
than otherwise. The arrangement of the stops is controlled to a great
extent by the feet, there being twelve separate pedals for this purpose,
so that the most beautiful and changeful effects can be made without
removing either hand from the key-board. There is also a pedal by
which all the stops of the organ may be gradually, one by one or
instantaneously, drawn on or shut off", thus producing the most mag-
nificent crescendo and diminuendo, as well as explosive effects. Thus
a tone which is scarcely heard at first can be augmented by degrees
until it makes the air quiver with its thunders, and then slowly sink
ao-ain to hushed repose ; or the crash can come without warning and
with almost deafening power, and as suddenly sink into music of which
the listener can catch but the slightest murmurs. The value of such
immense power under perfect control will be easily appreciated.

This great instrument, enclosed in a case of black walnut covered
with carved statues, busts, faces and figures in bold relief, is placed
upon a low platform, the outlines of which are in accordance with its
own. Its whole height is about sixty feet, its breadth forty-eight feet,
and its average depth twenty-four feet.

MANUFACTURE OF BOOTS AND SHOES BY MACHINERY.

The old system of making boots and shoes entirely by hand labor is
rapidly yielding to the march "of improvement, and will soon, to all ap-
pearances, be numbered with the relics of the past. This change in
the character of the manufacture of a great staple industrial product,
although slowly progressing for the last eight or ten years in the United
States under the spur of competition, has been rapidly consummated
within the last two years under the influences growing out of the pres-
ent civil war ; hand labor having proved entirely inadequate to supply
the immense demand for boots and shoes required by government for
its armies. Machines, therefore, have been invented, and are now in use,
executing the different operations necessary to the manufacture of such
articles, and with a rapidity and accuracy of action which far excel the
efforts of hand labor.

The following interesting account of a manufactory in New York
city, in which boots and shoes are made upon an extensive scale by
machinery, we derive from a recent number of the Scientific American :

Three large apartments are occupied by the operatives, mechanism,
and goods. The skins for the uppers" are first spread out, examined,
and selected according to the purposes for which they are required.
Different cutters then cut out the respective parts according to the size
and form required, and these are all arranged and classified. After
this these separate parts are given out in lots to be sewed by machines,
and those uppers which are intended for boots are crimped, and the
whole made ready for receiving the soles. The more heavy operations
of punching, sewing, pegging the soles -and finishing the articles, are

4*

46 ANNUAL OF SCIENTIFIC DISCOVERY.

iron, and the gas generator connected with it. The heated chamber
is of the usual form, but instead of a fireplace there are four passages
(two at each end of the chamber) leading downwards into four regen-
erators or chambers filled with loosely piled firebricks. The lower ex-
tremities of these four regen'erator chambers communicate with two
cast-iron reversing valves. The gas arriving from the producer through
a pipe is directed by the valve into one regenerator or other, according
to the position of the valve. The gas then ascends through the one
"regenerator, where it takes up the heat previously deposited in the
brickwork, and issues into the furnace at a point where it meets with a
current of heated air arising from the second regenerator to effect its
combustion. The products of combustion pass away through the oppo-
site regenerator and the reversing valves into the chimney flue. The
last-named regenerators receive at this time the waste heat of the fur-
nace, becoming heated at their upper extremity to the temperature
nearly of the furnace itself, but remaining comparatively cool towards
the bottom. Every hour or half-hour the direction of the currents is
reversed by a change of the valve lever, the heat before deposited in
the one pair of regenerators is now communicated to the air and gas
coming in, while the waste heat replenishes the second pair of regener-
ators. The gas producer consists of tAvo inclined planes upon which
the fuel descends, being gradually deprived in heating of its gaseous
constituents, and finally burnt to carbonic oxide by the air entering
through the grate at the bottom of the inclines. Water admitted at
the bottom also assists in the decomposition of the ignited coke at the
bottom, converting the same into carbonic oxide and hydrogen gas.
The saving of fuel which has been effected by this arrangement
amounts to from forty to fifty per cent. In the application to re-heat-
ing and puddling furnaces, a saving of iron has been effected, owing to
the mildness of the gas flame, of from three to four per cent, of the en-
tire quantity put in ; the iron also welds more perfectly than it does in
the ordinary furnaces. Smoke is entirely obviated. By another ar-
rangement the regenerative principle has been applied also to coke
ovens, the result being that the separation of the coke from its gaseous
constituents is effected without losing the latter. In placing the coke
ovens, constructed on this plan, near the works where the iron is pud-
dled and re-heated, the latter operation may be entirely effected by the
gas generated in producing the coke necessary for the blast furnace in
producing the pig iron. The gas resulting from the regenerative coke
oven may be used to heat the blast and boilers connected with the
blast furnace. These hitter improvements are now in course of being
carried into effect on a large scale. The gas produced from the last-
named producers is of a very illuminating character, and may, it is re-
ported, be used for that purpose in preference to the hydrocarbon now
manufactured for that purpose by a much more expensive process.

American manufacturers desirous of acquainting themselves in detail
with the principles of Siemans's furnace will find a descriptive paper by
the inventor in the Proceedings of the Society of Mechanical Engineers,
London.

MECHANICS AND USEFUL ARTS. 47

IMPROVEMENTS IN THE SCONCE OF WAR.

In accordance with the plan pursued during the last two years, we
give under the above head a summary of such inventions, discoveries,
and applications relative to the science of war, brought before the pub-
lic during the past year, as have seemed to the editor as most worthy of
notice.

IMPROVEMENTS IN GUN-COTTON.

At the British Association meetings of 1862, a joint committee of
chemists and physicists was appointed to inquire into and report on
the so-called "Austrian Gun-Cotton" At the last meeting of the
Association, a chemical report was submitted by Dr. Gladstone, and a
report on the mechanical portion of the question by Mr. J. Scott Russell.
We present first an abstract of Dr. Gladstone's report.

Chemical Report. Since the discovery of gun-cotton by Schonbein,
its application to war purposes has been frequently thought of; and
many experiments, with a view of using it, have been made, especially
by the French. Such serious difficulties have, however, presented
themselves, that the idea gradually came to be abandoned everywhere
but in Austria. Here experimentation was kept up, and it having
been reported on good authority that the experimenters had
succeeded in overcoming many of the difficulties encountered else-
where, the committee of the Association applied to the Austrian gov-
ernment for information, which was furnished them. The following is
a summary of the more important facts elicited. In the first place, the
gun-cotton prepared by Baron Von Lenk, the inventor of the Austrian
system, differs from the gun-cotton generally made in its complete con-
version into a uniform chemical compound. It is well known to chem-
ists that if cotton is treated with mixtures of strong nitric and sulphuric
acids, compounds may be obtained varying considerably in composition,
though they all contain elements of the nitric acid, and are all explo-
sive. The most complete combination (or product of substitution) is
that described as Co ? H 21 (9 NO 4 ) Ogo, which is identical with that
termed by the Austrian chemists trinitrocellulose, C 12 H T (3 NO 4 ) O 10 .
This is of no use whatever for the making of collodion ; but it is Von
Lenk's gun-cotton, and he secures its production by several precau-
tions, of which the most important are the cleansing and perfect dessic-
cation of the cotton as a preliminary to its immersion in the acids,
the employment of the strongest acids attainable in commerce, the
steeping of the cotton in a fresh strong mixture of the acids after its
first immersion and consequentim perfect conversion into gun-cotton,
the continuance of this steeping for forty-eight hours. Equally neces-
sary is the thorough purification of the gun-cotton so produced from
every trace of free acid. This is secured exclusively by its being
washed in a stream of water for several weeks. These prolonged
processes are absolutely necessary. It seems mainly from the want of
these precautions that the French were not successful. From the evi-
dence before the committee it appears that this nitro compound, when
thoroughly free from acid, is not liable to some of the objections which
have been urged against that compound usually experimented upon as

48 ANNUAL OP SCIENTIFIC DISCOVERT.

gun-cotton. It seems to have a marked advantage in stability over all
other forms of gun-cotton that have been proposed. It has been kept
unaltered for fifteen years ; it does not become ignited till raised to a
temperature of 136 C. (277 Fahr.) ; it is but slightly hygroscopic, and
when exploded in a confined space, is almost entirely free from ash.
There is one part of the process not yet alluded to, and the value of
which is more open to doubt, the treatment of the gun-cotton with a
solution of silicate of potash commonly called water-glass. Some Aus-
trian chemists think lightly of it ; but Von Lenk considers that the
amount of silica set free on the cotton by the carbonic acid of the at-
mosphere is really of service in retarding the combustion. He adds,
that some of the gun-cotton made at the Imperial factory has not been
silicated at all, and some imperfectly ; but when the process has been
thoroughly performed, he finds that the gun-cotton has increased per-
manently about 3 per cent, in weight. Much apprehension has been
felt about the effect of the gases produced by the explosion of gun-cot-
ton upon those exposed to its action. It has been stated that both ni-
trous fumes and prussic acid are among these gases, and that the one
would corrode the gun and the other poison the artilleryman. Now,
though it is true that from some kinds of gun-cotton, or by some meth-
ods of decomposition, one or both of these gases may be produced, the
results of the explosion of the Austrian gun-cotton without access of
air are found to contain neither of them, but to consist of nitrogen, car-
bonic acid, carbonic oxide, water, and a little hydrogen and light car-
buretted hydrogen. These are comparatively innocuous, and this
weight of evidence is, that the gun is less injured by repeated charges
of gun-cotton than of gunpowder, and that the men in casemates suffer
less from its fumes. It seems a disadvantage of this material, as com-
pared with gunpowder, that it explodes at a temperature of 277 Fahr. ;
but against the greater liability to accidents from this cause may be set
the almost impossibility of explosion during the process of manufacture,
since the gun-cotton is always immersed in liquid, except in the final
drying. 1 Again, if it should be considered advisable at any time, it
may be stored in water, and only dried in small quantities as required
for use. The fact that gun-cotton is not injured by damp like gunpow-
der is, indeed, one of its recommendations, while a still more important
chemical advantage which it possesses arises from its being perfectly
resolved into gases on explosion ; so that there is no smoke to obscure
the sight of the soldier who is firing or to point out his position to the
enemy, and no residuum left in the gun to be got rid of before another
charge can be introduced.

Physical Report. Mr. Russell stated, that greater effects are produced
by gases generated from gun-cotton than by gases from gunpowder,
and it was only after long and careful examination that the committee
were able to reconcile this fact with the low temperature at which the
mechanical force is obtained. The great waste of force in gunpowder
constitutes an important difference between it and gun-cotton, in which

1 In ten years' experience it is proved that this temperature is sufficiently high to
insure safety of manipulation ; 277 Fahr. is an artificial temperature, and artificial
temperatures accidentally produced are generally high enough to ignite gunpow-
der. The greater liability to accident from this cause can, therefore, scarcely be
admitted.

MECHANICS AND USEFUL AKTS. 49

there is no waste. The waste in gunpowder is sixty-eight per cent, of
its own weight, and only thirty-two per cent, is useful. This sixty-
eight per cent, is not only waste in itself, but it wastes the power of the
remaining thirty-two per cent. It wastes it mechanically, by using up
a large portion of the mechanical force of the useful gases. The waste
of gunpowder issues from the gun with much higher velocity than the
projectile ; and if it be remembered that in one hundred pounds of useful
gunpowder this is sixty-eight pounds, it will appear that thirty -two
pounds of useful gunpowder gas is wasted in impelling a sixty-eight pound
shot composed of the refuse of gunpowder itself. There is yet another pe-
culiar feature of gun-cotton. It can be exploded in any quantity instan-
taneously. This was once considered its great fault; but it was only a
fault when we were ignorant of the means to make that velocity anything
we pleased. Baron Von Lenk has discovered the means of giving
gun-cotton any velocity of explosion that is required by merely the
mechanical arrangements under which it is used. Gun-cotton, in his
hands, has any speed of explosion, from one foot per second to one foot
in YoVg- of a second, or to instantaneity. The instantaneous explosion
of a large quantity of gun-cotton is made use of when it is required to
produce destructive effects on v the surrounding material. The slow
combustion is made use of when it is required to produce manageable
power, as in the case of gunnery. It is plain, therefore, that, if we can
explode a large mass instantaneously, we get out of the gases so explo-
ded the greatest possible power, because all the gas is generated before
motion commences, and this is the condition of maximum effect. Itjs
found that the condition necessary to produce instantaneous and com-
plete explosion is the absolute perfection of closeness of the chamber
containing the gun-cotton. The reason of it is, that the first ignited
gases must penetrate the whole mass of the cotton, and this they do,
and create complete ignition throughout, only under pressure. This
pressure need not be great. For example, a barrel of gun-cotton will
produce little effect and very slow combustion when out of the barrel,
but instantaneous and powerful explosion when shut up within it. On
the other hand, if we desire gun-cotton to produce mechanical work,
and not destruction of materials, we must provide for its slower com-
bustion. It must be distributed and opened out mechanically, so as to
occupy a larger space, and in this state it can be made to act even more
slowly than gunpowder ; and the exact limit for purposes of artillery
Von Lenk has found by critical experiments. In general, it is found
that the proportion of eleven pounds of gun-cotton, occupying one cubic
foot of space, produces a greater force than gunpowder, of which from
fifty to sixty pounds occupies the same space, and a force of the nature
required for ordinary artillery. But each gun and each kind of projec-
tile requires a certain density of cartridge. Practically, gun-cotton is
most effective in guns when used as to ^ weight of powder, and oc-
cupying a space of l^th of the length of the powder-cartridge. The
mechanical structure of the cartridge is of importance as affecting its
ignition. The cartridge is formed of a mechanical arrangement of spun
cords, and the distribution of these, the place and manner of ignition,
the form and proportion of the cartridge, all affect the time of complete
ignition. It is by the complete mastery he has gained over all these
minute points that Von Lenk is enabled to give to the action of gun-
5

50 ANNUAL OF SCIENTIFIC DISCOVERY.

cotton on the projectile any law of force he pleases. Its cost of pro-
duction is considerably less than that of gunpowder, the price of quan-
tities which will produce equal effects being compared. Gun-cotton is
used for artillery in the form of a gun-cotton thread or spun yarn. In
this simple form it will conduct combustion slowly in the open air, at a
rate of not more than one foot per second. This thread is woven into
a texture or circular web. These webs are made of various diame-
ters, and it is out of these webs that common rifle cartridges are made,
merely by cutting them into the proper lengths, and inclosing them in
stiif cylinders of pasteboard, which form the cartridges. (In this shape
its combustion in the open air takes place at a speed of ten feet per
second.) In these cylindrical webs it is also used to fill explosive
shells, as it can be conveniently employed in this shape to pass in
'through the neck of the shell. Gun-cotton thread is spun into ropes in
the usual way up to two inches diameter, hollow in the centre. This
is the form used for blasting and mining purposes ; it combines great
density with speedy explosion. The gun-cotton yarn is used directly
to form cartridges for large guns by being wound round a bobbin so as
to form a spindle like that used in spinning-mills. The bobbin is a hol-
low tube of paper or wood, the object of the wooden rod is to secure in
all cases the necessary length of chajnber in the gun required for the
most effective explosion. The gun-cotton circular web is inclosed in
close tubes of India-rubber cloth, to form a match line, in which form it
is most convenient, and travels with speed and certainty. In large
quantities, for the explosion of mines, it is used in the form of rope, and
in this form it is conveniently coiled in casks and stowed in boxes. As
regards conveyance and storage of gun-cotton : it results from the fore-
going facts, that one pound of gun-cotton produces an effect exceeding
three pounds of gunpowder in artillery. This is a material advantage,
whether it be carried by men, by horses, or in wagons. It may be
placed in store, and preserved with great safety. The danger from
explosion does not arise until it is confined. It may become damp and
even perfectly wet without injury, and may be dried by mere exposure
to the air. This is of great value in ships of war, and in case of danger
from fire, the magazine may be submerged without injury. As regards
its practical use in artillery, it is easy to gather from the foregoing gen-
eral facts how gun-cotton keeps the gun clean and requires less wind-
age, and therefore performs much better in continuous firing. In gun-
powder there is sixty-eight per cent, of refuse, or the matter of fouling.
In gun-cotton there is no residuum, and therefore no fouling. Exper-
iments made by the Austrian committee proved that one hundred
rounds could be fired with gun-cotton, against thirty rounds of gun-
powder. From the low temperature produced by gun-cotton, the gun
does not heat. Experiments showed that one. hundred rounds were
tired with a six-pounder in thirty-four minutes, and the gun was raised
by gun-cotton to only 122 Fahrenheit, whilst one hundred rounds
with gunpowder took one hundred minutes, and raised the temperature
to such a degree that water was instantly evaporated. The firing with
the gunpowder was, therefore, discontinued ; but the rapid firing with
the gun-cotton was continued up to one hundred and eighty rounds
without any inconveniencc > . The absence of fouling allows all the
mechanism of a gun to have much more exactness than where allow-

MECHANICS AND USEFUL ARTS. 51

ance is made for fouling. The absence of smoke promotes rapid firing
and exact aim. There are no poisonous gases, and the men suffer less
inconvenience from firing in casemates, under hatches, or in closed
chambers. The fact of smaller recoil from a gun charged with gun-
cotton is established by direct experiment. Its value is of the recoil
from gunpowder, projectile effect being equal. To understand this
may not be easy. The waste of the solids of gunpowder accounts for
one part of the. saving, as in one hundred pounds of gunpowder sixty-eight
pounds have to be projected in addition to the shot, and at a much higher
speed. The remainder Von Lenk attributes to the different law of
combustion. But the fact is established. The comparative advanta-
ges of gun-cotton and gunpowder for producing high velocities are
shown in the following experiment with a Krupp's cast-steel gun, six-
pounder. With ordi nary charge thirty ounces of powder produced 1 ,338
feet per second. With charge of thirteen and one-half ounces, gun-cot-
ton produced 1,563 ft. The comparative advantages in shortness of
gun are shown in the following experiments, twelve-pounder :

Velocity
Calibers. Charge. feet per second.

Cotton, length 10 . . 15.9 oz. . 1,426

Powder, " 13^ . 49 (normal powder charge) . . . 1,400
Cotton, " 9". . 17 1,402

As to advantage in weight of gun, the fact of the recoil being less in
the ratio of 2 : 3 enables a less weight of gun to be employed, as well
as a shorter gun, without the disadvantage to practice arising from
lightness of gun. As regards durance of gun, bronze and cast-iron
guns have been fired 1,000 rounds without in the least affecting the
endurance of the gun. As regards its practical application to destruc-
tive explosions of shells, it appears that from a difference in the law of
expansion, arising probably from the pressure of water in intensely-
heated steam, there is an extraordinary difference of result, namely,
that the same shell is exploded by the same volume of gas into more
than double the number of pieces. This is to be accounted for by the
greater velocity of explosion when the gun-cotton is confined very
closely in very small spaces. It is also a peculiarity that the stronger
the shell, the smaller the fragments into which it is broken. As "re-
gards mining uses, the fact that the action of imn-cotton is violent and

f^ *-^ ^j

rapid in exact proportion to the resistance it encounters, tells us the
secret of its far higher efficacy in mining than gunpowder. The
stiongcr the rock, the less gun-cotton, comparatively with gunpowder,
is necessary for the effect ; so much so that while gun-cotton is stronger
tl .an powder as three to one in artillery, it is stronger in the propor-
tion of 6.274 to 1 in a strong and solid rock, weight for weight. It

CT5 C^ ^j

ia the hollow-rope form which is used for blasting. Its power of split-
ting up the material is regulated exactly as wished. As regards mili-
tary and submarine explosion, it is a well known fact, that a bag of
gunpowder nailed on the gates of a city will blow them open. In this
case gun-cotton would fail. A bag of gun-cotton exploded in the
same way is powerless. If one ounce of gunpowder is exploded in
scales, the balance is thrown down ; with an equal force of gun-cotton,
nothing happens. To blow up the gates of a city, a very few pounds
of gun-cotton, carried in the hand of a single man, will bo sufficient,

52 ANNUAL OF SCIENTIFIC DISCOVERT.

only be must know its nature. In a bag it is harmless ; exploded in a
box it will shatter the gates to atoms. Against the palisades of a for-
tification : a small square box containing twenty-five pounds, merely flung
down close to it, will open a passage for troops ; in actual experience
on palisades a foot diameter and eight feet high, piled in the ground,
backed by a second row of eight inches diameter, a box of twenty-five
pounds cut a clean opening nine feet wide. To this three times the
weight of gunpowder produced no etfect whatever, except to blacken
the piles. Against bridges : a strong bridge of oak, twenty-four feet span,
was shattered to atoms by a small box of twenty-five pounds laid on its
centre ; the bridge was not broken, it was shivered. As to its effects un-
der water : in the case of two tiers of piles, in water thirteen feet deep,
ten inches apart, with stones between them, a barrel of one hundred
pounds gun-cotton, placed three feet from the face and eight feet under
water, made a clean sweep through a radius of fifteen feet, and raised
the water two hundred feet. In Venice, a barrel of four hundred pounds
placed near a sloop in ten feet water, at eighteen feet distance, threw it in
atoms to a height of four hundred feet. All experiments made by the
Austrian Artillery Committee were conducted on a grand scale,
thirty-six batteries, six and twelve pounders (gun-cotton) having been
constructed, and practised with that material. The reports of the Aus-
trian Commissioners are all based on trials with ordnance, from six-
pounders to forty-eight-pounders, smooth bore and rifled cannon. The
trials with small fire-arms have been comparatively few, and are not re-
ported on. The trials for blasting and mining purposes were also made
,on a large scale by the Imperial Engineers' Committee.

Sir William Armstrong said it was impossible to listen to the report
which had been read without being very much impressed with the great
promise there was of gun-cotton's becoming a substitute for gunpowder ;
but at the same time there were certain peculiar anomalies about it
which he certainly should like to have cleared up, and until they were,
they could not feel that perfect confidence in the results that they
wished to do. In the first place, with regard to the heat evolved, they
were told that, with such a quantity of gun-cotton as would produce a
given quantity of gas, a certain initial velocity was imparted to the
projectile, and that the heating effect upon the gun was much less than
when a similar -velocity was produced by an equivalent quantity of
gunpowder. The absence of heat in the gun implied an absence of
heat in the gas. Where was the projectile force to come from, if there
was no heat in the gas ? He could not, for his part, conceive how it
was possible of explanation. The next point that occurred to him was
with regard to the recoil. It was stated that the recoil was very much
less. That was ascribed to the absence of solid inert matter in the
charge, which, in gun-cotton, was next to nothing. If the recoil was
only two-thirds that of gunpowder, it would require, in order to account
for that difference, a much larger quantity of solid matter than there
really was in the case of gunpowder. The report stated that the use
of gun-cotton enabled them to reduce the length erf the gun. It was
quite certain, however, that with a short gun they could not get an
equal initial velocity as with a long gun. If the initial velocity were
increased, there was more danger of bursting the gun than with gun-
powder. Because, if they got any velocity, or an equal velocity with

MECHANICS A1STD USEFUL AETS. 53

the shorter gun, it must be concluded that it was done by virtue of a
greater initial pressure and an earlier action upon the shot. That
necessarily implied a greater strain upon the gun at the first explo-
sion, and that would necessitate the employment of stronger guns. He
should have expected a smaller velocity by a shorter gun, for the ac-
tion of the gas was necessarily shorter than in a longer gun. The heat
question, however, was to him the greatest puzzle of all. How they
could have the propelling power without heat in the gas, and if they
heated the gas, how they escaped heating the gun, he could not under-
stand. Prof. Pole said he was quite unable to give any explanation of
the difference of recoil. If the shot left the gun with the same velocity
as when fired with gunpowder, it was natural to suppose that there
must be the same quantity of recoil. Mr. Siemans, having briefly spo-
ken on the dynamical question involved in the matter, suggested that
the greater heat imparted to the gun in the case of gunpowder might
be owing to the greater amount of solid matter, which, taking up the
great heat of the gases under a pressure of some four hundred atmos-
pheres, imparted a portion of the same by radiation to the side of the
gun, while in the case of gun-cotton gases only were produced, which
could only impart heat to the gun by the slower process of conduction,
and left a larger margin of heat to be developed in force by expansion.
Admiral Sir E. Belcher thought that the reason the gun was not heat-
ed by an explosion of gun-cotton might be because the gases had not
time to heat-the gun, owing to the rapidity of the explosion, which was
slower in the case of gunpowder ; or that it might arise from the great-
er amount of fouling in the case of gunpowder. Mr. Scott Russell then
said he would endeavor to clear away the many difficulties which at-
tended this very difficult subject. How was it that in gunpowder and
in gun-cotton, where there were equal quantities of gas put in, the gas
in the case of gunpowder was raised to an enormously high tempera-
ture, and came out at an enormously high pressure, showing that they
had gas enormously expanded by heat ; whereas in the case of gun-cot-
ton the gas came out quite cool, so that you might put your hand upon
it, and the gun itself was quite cool ? He (Mr. Russell) had a theory.
Steam was a gas, and steam expanded just by the same laws as other
gases did. A great deal of the gas of gun-cotton happened to be steam.
Let them conceive one hundred pounds of gun-cotton shut up in a cham-
ber that just held it. They had got there all the gases that had been spo-
ken of, but they had also got twenty -five pounds of solid water about
one-third of a cubic foot of water in that chamber. What did they do
with it ? They put fuel, they put fire to it. They heated the whole
remaining pounds of patent fuel. If, then, they considered the gun-cot-
ton gun as the steam-gun, they got rid of two difficulties. They would
have, first, the enormous elasticity of steam ; and secondly, they would
get the coolness of it. They all knew that if they put their hand to
expanded high pressure steam, it had swallowed up all the heat and
came out quite cool. He believed that the gun-cotton gun was neither
more nor less than Perkins's old steam-gun, with only this difference,
that you bottled up the fuel and water, and let them fight it out with
each other. They did their work, and came out quite cool. He hoped,
however, that it was understood that he did not dogmatize. He put
all he had said with a note of interrogation upon it. Prof. Tyndall
5*

54 ANNUAL OF SCIENTIFIC DISCOVERT.

said he thought that a note of interrogation ought to be put to what
Mr. Russell had said.

The subject was considered of so much importance that the Associa-
tion not only reappointed the joint committee to continue the inves-
tigations, but passed a resolution requesting the government to investi-
gate the matter separately.

Submarine Batteries, or Torpedoes. M. F. Maury, formerly
an officer in the United States service, who was present, re-
marked in the course of the above discussion, that Mr. Rus-
sell's report " was important as affording an element of security by giv-
ing the preponderance on the side of defence. Ever since steam had
been applied to purposes of naval warfare, it had been considered a
matter of very great doubt by many professional men how far ordinary
steamers and men-of-war, where forts were to be passed at the mouth
of a river, were capable of sustaining the fire of such forts and passing
up the river. And to show that there was ample time for them to do
so, they had only to recollect the fact of steamers having fought forts
for several hours. In the Crimea and at Charleston, the steamers
had remained under fire for several hours, a much longer time than
was necessary to enable them to pass the forts and go higher up the
river into a place of safety, where they could do damage to the enemy.
Tron-clads had rendered this much more easy than it had previously
been. If, then, their principal defences failed them at the mouth of a
river in this way, the question was whether they should not have re-
course to mining for the destruction of the invading vessels ? He him-
self had been engaged upon the subject. He found this difficulty in em-
ploying gunpowder, that in order to be sure of destroying the vessel as
she passed in a given line by means of gunpowder, the magazines must
be in actual contact, or very nearly in actual contact, with the side of
the vessel ; otherwise, the probability was that the vessel would not be
destroyed. Recently they had the intelligence of a vessel having had
a mine exploded under her on the James River. That magazine con-
tained several thousands of pounds of powder. The vessel did not
know that the mine was there ; but the mine did not destroy the ves-
sel. It merely threw up a column of water, which washed some of the
men overboard. His own conclusion was that to make sure of destroy-
ing a vessel after she had passed the forts, they must mine the channel
in such a manner that the vessel must come in contact with one or other
of the mines. It was found that wooden vessels to contain the pow-
der would not do. They would not confine the powder long enough to
produce a sufficient force. It was necessary to make them of stout
boiler-iron. It would not do to leave the magazines on the top of the
water, and it would not do to put them at the bottom, for then there
would be a cushion of water between the bottom of the ship to be de-
stroyed v and the magazine, which would protect the vessel. In short,
they had to anchor them beneath the surface with short buoy-ropes,
at a depth proportioned to the kind of vessel expected to come up.
But when they made the magazine of boiler-iron, they had to have
buoys to float it so large that they were always in danger of being
carried away by the vessels crossing the line of magazine. The plan
was to place those magazines in a ring in such a position that the ves-
sel in passing would have to come in contact with at least one and

MECHANICS AND USEFUL ARTS. 55

probably two of them. It was necessary to place those magazines of
powder so that when you saw the vessel in that range you had only to
bring the two poles of the galvanic battery together and make the ex-
plosion. There was, as already stated, a difficulty in using gunpowder.
But since gun-cotton had the remarkable effect of destroying a vessel
he did not know her strength at a distance of eighteen feet, and
that not vertically, but laterally, the question arose whether they might
not fortify and protect those channel ways by placing a ring of gun-
cotton magazines along the bottom ; but, at any rate, if that was not
necessary, they could float them at any depth, and out of reach of the
vessels generally using the channel. That appeared to him to be one
of the most important uses of gun-cotton, and it was one which would
give safety to cities which were some distance from the mouths of nav-
igable rivers. Admiral Belcher stated that the explosion of powder
under water was once done under one of his own vessels to clear away
ice. He placed it upon the ground, thinking that its explosion would
blow the ice clear of her bows without touching the vessel. There
was, however, sufficient water to form a cushion, and when the explo-
sion took place it only produced a great wave upon which the vessel
rose.

EXPERIMENTS AND RESULTS IN RELATION TO GUNS, ARMOR,

AND PROJECTILES.

Armor for Ships of War. Ever since iron-clad ships were invented,
there has been a conflict of opinions upon the subject of their armor.
The proper thickness, the mode of fastening it, whether single plates or
a number of thin ones are the best, with wood backing or without,
these are only a few of the questions bearing upon the subject which
have received attention. That some one plan has not been universally
adopted is owing to obvious natural causes. Each person or govern-
ment thinks himself or itself best qualified to judge where his or its im-
mediate interest is at stake.

In this country, we have more generally adopted the series of thin
plates in preference to heavy single ones ; although there are some ex-
ceptions to this statement. In Europe, the reverse is true. Thus far
we have had more practical experience with iron-clad ships than any
other people. The last to adopt these engines of war, we have been
the first to put them into actual service, and our success has been wholly
with the combinations of thin plating. The gunboats on the Western
rivers Conestoga and Lexington were plated with solid iron 2J-
inches in thickness, yet they were completely riddled in the attack on
Fort Henry by the ordinary guns at that point ; so also was the Essex
before her reconstruction. The Ericsson batteries are all armored
on the principle of many layers of thin plates, and they have proved
themselves impregnable, so far, to every assault. The arguments in
favor of thin plates may be summed up in the following list: It is
claimed that they are stronger for a given weight of metal than thicker
forged armor, by reason of ^he " scale " or cuticle being preserved in-
tact, as well as by the intimate relations of the fibers which occur when
small quantities of the metal are subjected to intense pressure ; for this
reason it is apparent that the structure of thin plates must be, cetens
paribus, more reliable than forged ones. By the same reasoning, how-

56 ANNUAL OF SCIENTIFIC DISCOVERY.

ever, some may assert, that if the requisite machinery existed in this
country for giving the same proportionate tenacity and tensile strength
to heavy single plates, as good results would be produced. This se-
quence, although a natural one, is not, it seems by experience, a cor-
rect one. A combination of thin plates is said to be more effective in
resisting the impact of a heavy shot than a single plate of the same
thickness, by reason of their elasticity or reaction after the instant of
percussion. All experience goes to prove this assertion ; where heavy
plates have been shattered to fragments, the thin ones have been dis-
placed and bent, but not destroyed, and the injuries to them rarely ex-
tend through a whole section of armor. The heavy plates, when
smashed, require much time and expense for their renewal, and are at
best a poor substitute for thinner coats in many layers.

Recent improvements have rendered the thin plates still more ef-
fectual. The gunboat Essex, after her misadventure at Fort Henry, on
the Cumberland river, was taken to St. Louis and there re-clad on the
forward casemate with iron plates only one inch thick ; under these
were placed India-rubber sheets one inch thick, the whole being in-
clined at an angle of 45 upon a wooden backing of oak 16 inches
through. Thus defended, the ship went into service.

" In the action between this gunboat, commanded (at that time) by
Commodore W. D. Porter, and the batteries at Vicksburg, Port Hud-
son, and other points on the lower Mississippi River, the forward caser
mates were struck repeatedly by solid shots, varying from 32 to 128
pounds, some of which were fired from rilled guns at short range. None
of those shots penetrated the forward casemate, but some of the larger
ones indented the armor plates, started the wood-work, and broke in
pieces, showing that the force of the shot was entirely spent. The
after-casemates, covered with iron of the same thickness, and made by
the same manufacturers, but without india-rubber, were penetrated in
several places by shots fired from the same batteries and similar guns ;
in all, over 125 shots struck this vessel at about the same range, proving
that this thickness of iron affords no protection when placed immedi-
ately upon a solid timber support." Scientific American.

Corrugated Armor Plates. - - The following is an abstract of a paper on
the above subject, read to the British Association, 1863, by Mr. George
Bedford. The principle of protecting ships by thick plates of iron against
projectiles of steel or homogeneous iron, hardened and tempered, would
appear to be erroneous, for the following reasons, namely, that iron
plates must always be softer than the projectile, while the latter has an
almost unlimited advantage in the force which can be o-iven to it by

' ^

strengthening guns so as to bear very large charges, and thus gain in-
crease of velocity with increased weight of shot. Still more is this the
case if flat-headed projectiles, hardened and tempered as the Whit worth
shell and shot, are to be provided against. The method which I pro-
pose is founded upon two principles of strength, - - cohesive strength and
mechanical strength. The plates being made of steel, hardened and
tempered as nearly as possible up to the cohesive strength of the Whit-
worth shot and shell, are of two kinds, --one thick and corrugated, the
other thinner and plain. The steel corrugated plates, which "are three
inches thick, are placed upon the thinner plates of one inch, also tem-
pered, arid bolted through the skin of the ship to the ribs in the iron

MECHANICS AND USEFUL ARTS. 57

ship, or to the timbers in a wooden one. If iron plates of the corru-
gated form were backed with an inch plate of steel, hardened and tem-
pered, they would, I think, prove impenetrable ; and even smooth iron
plates of 4 inches thus laid upon steel would be more effective than iron
plates even of 7 inches thick, backed by timber. In explaining the
mode in which I conceive this kind of compound armor-plating to act,
it is necessary to consider to what the great force of flat-headed projec-
tiles is due. It will be admitted that this is not to be attributed to the
velocity of the shot, but to its flat form and great cohesive strength 5
because spherical and conical projectiles sent with higher velocity do
not pierce iron plates. The rationale of the punching action may not
yet be quite clearly understood, but this much seems to be established,
that a flat-headed shot pierces because its whole force is applied equally
in one direction, and free from the lateral resistance which the conical
and round shot meet with. I venture also to state that the suddenness
of the impact of such a body has much to do with the effect; it would
seem that time is an important element in the consideration, and there-
fore if this perfect impact can be delayed, and still more, if it can be
prevented altogether, the piercing of the plate will not be effected. As
an illustration of the difference between force applied with time and
force without it, may be pointed out the simple experiment of striking
an anvil with a small hammer, and placing the same force in weight
gradually, or with time. In the first case, the force is not conducted
away into the mass of the anvil, but is spent in repelling the hammer,
and possibly in breaking it into fragments. This is also exemplified in
the smashing of round shot against an iron target of proper thickness.
In the case of the hammer's being pressed upon the anvil, no effect is
produced upon either the one or the other. Another familiar illustra-
tion is in the effect of soft materials, such as gun wads or tallow candle,
being sent at high velocity through wooden planks, and, as frequently
occurred, killing persons struck by them. Velocity, then, may be de-
scribed as force with the least possible element of time ; the best exam-
ple, perhaps, of which is electric force in the form of lightning. The
analogue of this force is seen in the flash of flame which occurs when a
shot strikes at high velocity upon an iron plate. Now, the object of
the steel plates, being hardened and tempered, is to delay the shot by
its cohesive strength, and to prevent, by the corrugated surface, the
whole area of the flat-head projectile bearing upon the plate at the
same moment of impact. The shot is delayed partly by this means,
and partly by meeting with a metal as hard and tough as itself, and
thus time is allowed for the conduction of the force away into the sur-
rounding metal without fracture and penetration ; the objects which I
consider most important being, first, to prevent penetration of the outer
plate, and to oppose a shot which did pierce it, when it has expended
its force, by covering the skin of the ship with a thin steel plate, in
preference to increasing the thickness of the outer plating. The me-
chanical strength of this arrangement of plates consists in the double
arch form combined with a certain amount of " play " and elasticity, ob-
tained by fixing the corrugated plate upon a flat one. The flat action
of the projectile is also prevented by, as it were, converting it into a
round head or a hollow head before it reaches the inner plate. The
space between the corrugations being about four and a half inches, a

58 ANNUAL OF SCIENTIFIC DISCOVERT.

flat-head shot of five inches diameter would begin to bear upon less
than one square inch of plate if it struck across a furrow, while if it
struck upon a corrugation, the surface pressed upon, even with a seven-
inch shot, would be seven square inches instead of thirty-nine, which is
the area of impact of a shot of this diameter upon a flat surface*. In a
large proportion of hits the shot would have to cut through in an ob-
lique direction about six inches of metal before reaching the plain plate.
The advantages of the plan proposed are, besides the protection of the
ships, the reduction of the weight of armor much below that contem-
plated for the new.ships of war. The saving of at least one inch in
thickness of plates would give a reduction of 100 tuns ; and if it should
be found that timber backing can with this armor be dispensed with,
a point now so much the subject of inquiry, the reduction of weight
would be about 250 tuns in a ship of the Warrior class. The extra
cost would be to a great extent met by the saving in the thickness of
plates and the timber backing.

Interesting English Experiments with Iron-targets, Whitworth and
Armstrong guns. Some interesting experiments with guns and ar-
mor-plates, made under the direction of the British ordnance board, have
been reported during the past year. The following account of trials
on the 3d and 1 7th of March, at Shoeburyness, will be found especially
worthy of notice. Upon the first named date, four guns were tried,
viz: One of Whitworth's, of 71-inch bore, with hexagonal rifled

Zi * >

grooves; one Armstrong 9-inch smooth-bore, and one 10|-inch bore,
rifled ; also one of Thomas's rib-rifled 7-inch bore. The target con-
sisted of several iron plates, 5, 6, 7 and 8 inches in thickness, 20
inches in width, and 8 feet in length. It was 11 feet in width and
8 feet high, with an embrasure of 31 by 21 feet. The plates Avere
fastened to huge bars of iron, placet! vertically and crosswise, secured
with 3-inch through bolts, screwed up behind. This target represented
the strongest experimental gun-shield which has yet been constructed.
The first experiment was made with Whitworth's 7-inch muzzle-load-
ing rifled gun, weighing 71 tuns, and nominally throwing a 120-pound-
er shot, though in reality made for projectiles of the weight of 150
Ibs. and upward. This was loaded with 25 Ibs. of powder and a flat-
headed hardened projectile, weighing 137 Ibs. It struck on the left
side of the target with terrific force, emitting, at the moment of con-
tact, a sheet of flame as broad and vivid as if another cannon had been
fired from, the mark in reply. The massive bar frame of 12 inches
solid iron behind the plates was dislodged, and an 8-inch plate was
cracked. The impact velocity of the shot was 1,240 feet per second.
The next shot was from the Armstrong 9-inch smooth-bore, with a 100-
pound round shot of wrought-iron, and a charge of powder of 25 Ibs.
The missile struck full upon the thick side of the target with a velocity
of 1,470 feet per second, inflicting a tremendous circular dent 2^
inches deep, cracking one of the inner plates of the target, and knock-
ing ofT one of the massive bolt-heads. The target was roughly shaken,
but not pierced.

A new bolt was screwed into it and the third shot was fired from the
10|-inch Armstrong shunt-rifled gun. This piece of ordnance weighs
ll|tuns. It is rilled with 10 deep grooves on the shunt principle
the shot enters freely by the muzzle down one series of grooves, but it

MECHANICS AND USEFUL AETS. 59

is regularly sliunted into another series, along which it comes out when
the gun is fired, and the grooves for exit being shallower than those for
entrance, they, as it were, squeeze the shot with sullk-ient force to make
it take the form of rifling, and give it the rotation on its axis. It was
loaded with a hollow-headed conical-shaped shot, 19^ inches in length,
weighing 230 Ibs., with a 45-lb. charge of powder behind it. It sent
the shot with a velocity of 1,405 feet per second full on the thick part
of the target, inflicting a broad damaging indent, shaking the whole
structure a good deal, and cracking an outer upper plate; but still
there was no through penetration.

The next shot was by Thomas's 7-inch muzzle-loader. This gun
was 11 feet 6 inches long, rifled on a new plan, somewhat in ap-
pearance like the canon raye of the French, but with this difference,
that instead of three grooves it has three ridges projecting nearly an
inch into the bore ; the elongated projectiles, 2-1 diameters long, fitting
into and between the ridges. The shot fired was a wrought-iron one
of 151 Ibs. weight, with a charge of 25 Ibs. of powder." It was the
first time the gun had ever been fired, and it hit the white spot aimed
at so truly as quite to obliterate the mark, doubling up the shot itself
into the form of a huge cauliflower, and making an indent almost as
severe as that of the 100-pounder smooth-bore. Its velocity was 1,21-5
feet per second when it struck. The target appeared much shaken,
but was still impenetrated.

Mr. Whitworth's gun was then again fired, at the same range and
with the same charge oT powder and shot. The shot was aimed at
the untouched plates, below the embrasure, and so close to the ground
that the projectile struck the earth first, making a deep furrow"; and,
of course, considerably diminishing the force of its blow. For this
reason it made but a very slight impression, and did no injury to the
target that was worth speaking of.

The 10-inch Armstrong gun was again fired, with a charge of 45
Ibs. of powder, and a wrought-iron shot of 230 Ibs. This tremendous
missile injured the target considerably, and sent fragments of it flying
through the air in all directions, with a hoarse roar that was terrible to
hear. The force of this blow broke some of the plates in fresh places,
knocked the head off one of the bolts, and drove out another like a
rocket.

Thomas's gun was again fired, with 27-1 Ibs. of powder, and a steel
bolt weighing 133 Ibs. Its maker stated he was afraid of his gun, as it
was too deeply bored ; and it was, therefore, fired with electricity, from
a battery some distance off. When the charge was ignited, the gun
burst into fragments ! The explosion was so complete that the masses
were scattered in every direction, one piece weighing nearly a ton
being thrown to a distance of 140 yards. The experiments were then
terminated for the clay. This gun had a steel interior tube, and an
iron breech banded with a shrunk hoop 13 inches in width and 3
inches thick. The total diameter where it burst at the breech was 29
inches. It was claimed that the victory remained with the target.

On the 1 7th of March following, the experimentation commenced
on the third was continued. The target used on this occasion was 12
feet square, formed of three great plates of the best rolled iron ; the
upper one being 5-1 inches thick, the middle one 1\ inches, and the

60 ANNUAL OF SCIENTIFIC DISCOVERY.

lower one 6i inches. One-half of the target was backed with teak-
wood planking 10 inches in thickness, and the wood was backed with
inside plates of iron 2^ inches in thickness. The other half of the
target had. the outside plates bolted to strong vertical iron ribs, but
had no teak backing or inner skin plates. Six feet square of the
target, therefore, were formed of 10, 0, and 8 inches in thickness of
iron and 10 inches of teak. The quality of the plates was superior
to any ever tested in a target. The firing was at a distance of
200 yards ; and the guns tried consisted of the old smooth 68-pounder,
Armstrong's 110-pounder service gun (with special steel shot cut
down at the base to reduce them to 65 Ibs. weight), Armstrong's
300-pounder muzzle-loading rifled shunt gun, Whitworth's muzzle-
loading 150-pounder or 7-4nch gun, and Thomas's 9-inch or 300-
pounder rifled muzzle-loading gun. Both these latter were made by
Colonel Anderson, at Woolwich, on the built-up coil principle adopted
by Armstrong; both were admirable specimens of workmanship,
though, before the experiments commenced, Whitworth's gun was
found to have a crack or flaw in the centre steel tube round which the
coils of wrought-iron are wound and welded in the course of manu-
facture. This defect prevented its being used in the course of the
experiments except for one discharge with a line-shell. Thomas's gun
was an enormous piece of ordnance, nearly 18 feet long, weighing 1G
tons, and with a thickness of 1 7 inches of metal around the powder
chamber at the breech. Though nominally a 300-pounder, this gun is
claimed to be capable of throwing projectiles of various forms and
weight, from 250 Ibs. up to 410 Ibs. Armstrong's 300-pounder weighs
less than 1 2 tons.

The first shots, three in number, were fired from the old smooth-bore
68-pounder, with the usual service charge of 16 Ibs. of powder; these
were directed against the 5^, 6-J- and 7^-inch plates, and were immedi-
ately followed by three shots from Armstrong's 110-pouncler, loaded
with special steel projectiles weighing 65 Ibs., and fired with the same
service charge as the smooth-bore 68-pounder. Where the 68-pounder
had struck, the indentation varied from 2 inches to 3 inches in depth ;
where the steel shot of Armstrong's had hit, the mark Avas in one case
deeper, and the plate showed a perceptible' crack about 8 inches long,
though apparently of very trifling depth. But the most careful exam-
ination failed to discover any mark on the back of the target to show
that it had been hit at all.

The next shot was fired from Armstrong's 300-pounder, loaded with
a conical steel shot of 296 Ibs. weight, and fired with 45 Ibs. of powder.
This tremendous missile struck, with a velocity of 1,298 feet per sec-
ond, full upon the centre of the 7^-inch plate, where it was backed,
driving in a circular piece of iron 10 inches in diameter quite through
the plate, bending in the whole plate itself to the depth of an inch and
a half, and buckling its ends outwards more than an inch. The mas-
si v<> wrought iron girder which crossed the whole back of the target
horizontally was bent out and broken in several places, as were also
the inner ribs ; the 2^-inch skin was bulged and cracked, the rivet
beads loosened, and many knocked off altogether. The examination
showed that the target had received a most serious shake, though, from
the wonderfully good quality of the iron, there was little of actual frac-

MECHANICS AND USEFUL ARTS. 61

tnre, except in the spot on which the shot itself had struck. Had the
object struck been a ship's side, the damage would have caused a most
serious leakage. It is hardly possible, however, to institute compar-
isons between any armor-dads yet known and this target, as. no sea-go-
ing vessel could possibly carry the masses of iron that were here fired
at, although a floating battery might. This last steel shot rebounded
from the target, and, when examined, showed little signs of damage. All
competing artillerists at Shoeburyness seem to agree that the range
for testing the powers of rilled guns should not be less than 1,000 yards,
at which distance the force of smooth-bore projectiles would be re-
duced one-half, while the rifled shot would be flying at nearly their
greatest impetus.

The next shot was from Sir William's 300-pounder, loaded with a
cast-iron shell weighing 286 Ibs., and charged with 1 1 Ibs. of powder.
This was fired with the usual 45 Ibs. charge, and struck full in the
centre of the 5 i-inch backed plate with a velocity of 1,330 feet per
second. It shattered its way completely through it, leaving a rough
hole about 10 inches in diameter, and then burst in the inside, blow-
ing the teak to minute fragments, setting it on fire, breaking off many
of the rivet heads, and tearing the inner skins of iron, 2^ inches thick,
into rough shredded gaps, as if they had been so much cardboard.
When water had been procured and the fire in the wood extinguished,
it was seen at a glance that the question of the resistance which the
strongest British iron frigates would be able to offer to such ordnance
was settled in the most unpleasant manner. By the side of the target
was a powerful partition of wooden beams, and an examination of
this, after the shell had exploded, gave terrible proofs of its destruc-
tive powers. There was scarcely a square inch of its whole surface
that was not deeply penetrated with fragments of the shell of all
shapes and sizes, from one pound weight to ragged particles as minute
as small shot.

Mr. Whitworth's 150-pounder was next tried, loaded with a steel flat-
headed shell of 156 Ibs. weight, with a bursting charge of 6 Ibs. of pow-
der, and fired from the gun with 25 Ibs. of powder. This shell struck
within about five inches of the spot where Sir William's had struck,
burst and destroyed the teak backing. The Whitworth shell passed
quite through the plate and burst among the debris of splinters behind.
The hole in the plate was of the small, clean-cut, punched kind. It
was claimed that the result was equal to what had been accomplished
by Armstrong's gun, with a 286 Ib. shell and 45 Ibs. of powder. Ow-
insr to the flaw in its breech no further trials were made with this

gun.

Thomas's gun was the next competitor. Unfortunately the gun was
not well pointed, and its first 330 Ib. shot missed the target altogether.
The next shot, weighing 307 Ibs., and fired with a 50 Ib. charge of
powder, struck the hollow part of the target, where it was 7 T V inches
thick, and bent the plate. The third shot was more successful. It
was a steel projectile of 330 Ibs. weight, fired with the same charge.
It struck on the edge of the 7^-inch plate, and made a broken ind^n-
tation to the depth of 10^ inches, sufficient to establish the most alarm-
ing leak in the side of any vessel. The terminal velocities of both
these last shots were lower than any fired, which was attributed to
6

G2 ANNUAL OF SCIENTIFIC DISCOVERT.

what is believed to be the excessive pitch in the mode of ribbed rifling
adopted by Mr. Thomas.

Sir William Armstrong then fired his 300-pounder with an ordinary
cast-iron round shot, weighing 144 Ibs., with a charge of 45 Ibs. of pow-
der. The terminal velocity with which this struck the 7l-inch plate
on the unbacked portion was the highest attained no less than 1,636
feet a second - - and almost in exact proportion to its velocity was the
damage it inflicted. Not only was it indented larger and deeper than
any shot that had gone before, but on the inner side it broke the plate
both vertically and horizontally, leaving a cruciform tear nearly two
inches wide at the openings, besides shaking the target to its very
foundations.

The massive target was now so much damaged, both in plates and
fastenings, that further experiments became almost useless. The iron,
even where most torn, held together in a manner that was really won-
derful ; but Mr. Thomas had knocked off several of the massive screw
bolt heads, and the effect of the entire day's work had been so to bend
the plates and destroy the backing that there was really no part left
that afforded the means of a fair test of resistance.

The practical results elicited by the day's experiments seem to be
these first, that iron plates of 71 inches, or greater thickness, can be
produced with as much perfection, as to quality and strength, as those
of 4 inches ; secondly, that there are guns the fire of which the strong-
est armor-clads could not face and float for ten minutes.

Perhaps the most remarkable fact connected with these experiments
was the smashing of the target with a cast-iron shell. From previous
experiments it had been concluded that all cast-iron shot would break
in pieces in striking thick wrought-iron plates.

The Armstrong Gun.-- Confidence in the Armstrong gun in Great
Britain has been greatly diminished during the past year, both from
the public discussion of its merits in the public prints, and through the
publication of the report of a government committee appointed to in-
quire into the whole subject.

According to the Western Morning Mail, Mr. Armstrong has, since
the commencement of his appointment of government gun-founder,
" constructed not less than ten different kinds of guns ; that of each
kind he made and put into the government's hands a considerable num-
ber, and was paid for them, and that not one of all these cannon has
proved serviceable without great and expensive alterations. He made,
1 1 0-pounders, 120-pounders, both muzzle and breech loading ; 150-
pounders, 300-pounders, 200-pounders, 12-pounders, 40-pounders, 100-
pouuders ; and the only guns of all these which are even claimed to be
successful arc the 12-pounders. But of these we read that they have
been returned and are now having twelve inches cut off the muzzle to
make them safe. They will, consequently, when 'fixed,' be only
9-pounders, with a diminished range."

There are a number of Armstrong guns now in use in the British
navy, 1 1 0-pounders for the most part, but the committee report that
'^although useful as chase guns, they ought not to be introduced as broad-
side guns." The report adds that they are " not sufficiently powerful
to penetrate iron-plated ships, and are imperfect for general naval ser-
vice, owing to the diiliculty of managing and manuiacturing the vent

MECHANICS AND USEFUL ARTS. 63

pieces." The Duke of Somerset testified that " the Admiralty had a
report that the Armstrong gun had the greatest range and the greatest
power of penetration of any gun tried; but that when they came to
try ifc themselves, they found that the report was not confirmed by the
facts. For naval purposes at two hundred yards it certainly had not
the greatest power ; our old 68-pounder is a more powerful gun than
the Armstrong 100-pouuclcr."

Captain Wainwright of the iron-clad frigate Black Prince, in exami-
nation before the committee, stated that in a sea-way, the practice with
the Armstrong guns was very unsatisfactory, particularly in ricochet
practice, the smooth-bores beating them in accuracy. An attempt at
explanation was made, on the ground that the shot was delayed in the
Armstrong gun after the trigger was pulled, longer than in the old
smooth-bore guns, consequently the aim, in a rolling sea-way, must be
less accurate. Captain Wainwright stated that the Black Prince, which
lie commanded, being armor-clad, had very small ports, and that the
smothering sensation from the black smoke produced by these guns was
hardly endurable ; this he imagined to be from something in the wad ;
lie had no other conjecture to hazard.

19-inch Rifled Steel Guns. Krupp, the celebrated cast-steel manu-
facturer of Germany has recently furnished to the Russian Government
a number of 19 -inch rifled cast-steel guns, designed to throw a 300-
pound shell, or a 450-pound solid shot. The London Times gives an
account of some experimental firing with one of their guns, at St. Peters-
burg, with a view of testing certain shell, and the quality of a large lot
of 4 |-incli armor-plates, manufactured for the Russian government at
Sheffield, England. It says : " First, a series of cast-iron shells, 300
pounds each, were fired at different ranges, and then shells made by Krupp
were fired at the 4-i-inch armor-plates. The first shell, of hard cast-
steel, was 22^-inches long (two and a half diameters), with a flat end
4 inches in diameter. Fired with 50 pounds of powder at 700 feet dis-
tance, it passed through the plate, oak and teak backing, and broke
into many pieces, although filled with sand only. The second and third
shells were also of Krupp's steel, the same length, but with 6^-inch
ends. These shells pierced plates, wood, etc., and also went to pieces,
although only filled with sand. The fourth shell was made of puddled
steel the same dimensions as the second and third, went through iron,
teak, etc., but was only bulged up from 9 inches to 12 inches, and the
end flattened ; not a single crack being visible in the shell. The fifth
shell, the same as the fourth, passed through iron, teak, and a second
target, and went at least a mile beyond. The sixth and seventh were
from Krupp, and were charged with powder ; they were quite flattened,
9 inches in diameter. One exploded in the plate, the other in the
wood. The eighth and ninth shells were of cast-iron, and, although they
passed through the plates, were of course destroyed. The results on
the plates were highly satisfactory. In a space of 4 feet 6 inches by 3
feet C inches, eight holes were made without any crack of the slightest
description."

Resitting qualities of Hogs-hair Targets. The U. S. Bureau of Ord-
nance, Navy Department, have recently published the results of some
experimental trials to test the resisting qualities of targets made essen-
tially of hogs-hair, the invention of a Mr. Brady. The target used was

G4 ANNUAL OF SCIENTIFIC DISCOVERY.

made of 5 bales of hogs-hair, faced and backed with pine plank 4 inches
thick, and fastened with 28 wroughfc-iron bolts. Two of the bales had
been subjected to one and the same amount of compression, and two
others were compressed alike but differing" in degree from the former,
and the remaining bale, as stated by the inventor, was but slightly
compressed. The bales were bound with iron hoops. The target was
backed with 4 feet of solid clay.

Dimensions of Target. Eleven feet, three inches long ; four feet
wide ; three feet, three and a half inches thick.

The gun used was a rifled 50-pounder ; charge 3^- Ibs. cannon pow-
der; weight of projectile 38 Ibs. The result of the firing was unsatis-
factory ; the shot passing entirely through the bales and the clay back-
ing, and embedding themselves in a bank of earth 18 feet in the rear
of the target.

Wire-Rope Target. Experiments have been made at the Wash-
ington Navy Yard with a target devised by Mr. Hodge, consisting of
three thicknesses- of half-inch plate iron, backed by a tissue of wire-
ropes fourteen inches thick. The target was mounted on timber nine
inches thick, consisting, first, of two one-inch boards (one horizontal
and one vertical) and then of two layers of timber three and one-half
inches thick, disposed of vertically and horizontally. The dimensions,
of the target were as follows: Length, sixty-seven and one-half inches;
width, fifty and one-half inches ; iron thickness, fifteen and one-half inch-
es ; timber, nine inches. Two shots were fired at this target from a
eleven-inch gun, distance eighty-three feet. The first shot, a wrought
iron projectile weighing one hundred and fifty-six pounds, with a
charge of twenty-five pounds of powder, hit direct and passed clear
through the target. Shot No. two, cast-iron, weight one hundred six-
ty-five pounds, charge of powder fifteen pounds, hit direct, and, pass-
ing clean through the target, buried itself in an earth-bank to a depth
of nine feet six inches.

On the Results of Experiments in Gunner?/ ivitli Iron Target*.
In a discussion on this subject, before the British Association, 1863, Mr.
Calvin stated that the earlier experiments showed that four and one-
half inch plates at least were necessary to resist shot. This thickness
of iron still left the plate'liable to be hurt or fractured, and knocked off
even when not directly penetrated, and the extent to which it would
thus suffer would in some degree be regulated by the backing. The
plan adopted in the Warrior was simply that suggested by the idea of
bolting a plate of iron to the sides of a wooden ship. The iron skin of
the Warrior is covered with two layers of teak planking, each nine
inches in thickness, the one horizontal, the other vertical, and outside
of those is the armor-plate, four and one-half inches thick, secured by
bolts, screwed up with nuts inside of the ship. The wood backing
AVIS to prevent the injuries sustained by the plate from being communi-
cated immediately to the ship, but it afforded no effectual support to
the plate itself. The results of experiments with iron targets having a
rigid backing, composed wholly of iron, had demonstrated that this plan
was not desirable. The arrangement required for the armor-plating
of a ship was a strong front plate, in which deflection under blows
should be prevented, but which should have some cushion behind to
prevent the full concussion of the blow being communicated to the side

MECHANICS AND USEFUL ARTS. 65

of the ship. Mr. J. Nasmyth expressed his opinion that for armor-plates
to answer the end for which they were designed, they must be backed
by some elastic substance, and, in his opinion, that best adapted to give
the requisite elasticity was compressed wool. As Mr. Maury was present,
he should like to have his opinion on the subject of cotton, and
whether it had been found to answer so far as his experience went.

Mr. M. F. Maury, late an officer in the U. S. Xavy, said he had not
had an opportunity of gaining a great deal of experience on this sub-
ject, nor had he had an opportunity of witnessing the experiments that
had been made upon cotton. There had been experiments to test the
capability of cotton to resist cannon-balls, but the results had by no
means been satisfactory. He thought that, cotton had got a false repu-
tation. In the early days of the American difficulty, they thought that
cotton could resist balls successfully ; but when it came to" the test, they
found the bales did not answer the purpose. Mr. J. Scott Russell said
the whole course of experience had been to show that they must arrest
and shatter the shot at the earliest possible moment, and in the short-
est space of time when it struck the armor.

New Vent-holes for Artillery. A series of experiments have been
made during the past year at Shoeburyness, Eng., by the British Ord-
nance Committee, to ascertain how far a method now rather in favor
among French artillerists, by which a series of holes, about an inch in
diameter, are bored through the substance of the cannon near its muz-
zle, in order, by permitting a quick escape of gas, to diminish its recoil,
aifects the service of the piece as to range and accuracy. The experi-
ments were made with two brass 9-pounder ordinary smooth-bore
fieldpieces, which were loaded with the usual service charges, and
spherical shot. Five rounds were fired from each gun in succession,
the recoil of both being carefully measured after each discharge. They
were then shifted, so that each occupied the platform which had been
used by the other, when again more rounds were fired. The general
merits of the performances of each gun were exactly what were antici-
pated before a shot was fired. The recoil of the ordinary gun was, in
round numbers, just twice as great as that which had the holes bored
round the muzzle, while the range and accuracy of the latter were
scarcely more than half as good as those of the common piece. The
lateral escape of gas and flame through the side holes of the French
gun, if we may so call it, was very great indeed, so much so as to prove
at once that even if the gun otherwise possessed the most transient
merits, it could never be used either on shipboard, in casemates, or even
at embrasures. In the open air the trigger had to be pulled by a lan-
yard nearly twenty yards long. One half of the force of the explosion
evidently escaped through the side holes before the force of the powder
was expended on the shot, and virtually, therefore, the barrel of the
gun is shortened by as much of its length as is thus perforated. As a
general rule, the recoil of the gun is always in e:#iet proportion to the
force it exerts in propelling the shot, and anything which takes off
from this reooil, by allowing the gas generated by the explosion to es-
cape before it has done its Avork, just diminishes by so much the range,
and therefore the accuracy, of its fire. The results obtained with this
curiously-bored gun were enough to satisfy the Ordnance Committee
that the device in question was of no value.

G*

66 ANNUAL OF SCIENTIFIC DISCOVEEY.

India Rubber Breech Piece for Cannon. Numerous patents have
recently been taken, both in this country and Europe, for devices to
lessen the strain and liability of explosion in ordnance by the use of
vulcanized 'India-rubber or gutta-percha applied in the breech to con-
fine the air, against which the exploded powder will act, whereby the
sides of the bore are relieved from the immense strain of the ignited
charge. The objects of these inventions are to lessen the danger of
explosion and enable the gun to give a greatly-increased velocity to the
shot by using a larger charge of powder than is allowed or deemed safe
in the old kind of guns. A device recently patented by Horace H.
Day, of New York, consists essentially in inserting into the bottom of
the bore of the gun an India-rubber breech piece, or cushion, having
a conical recess at its base. Upon the top of this the charge and pro-
jectile are inserted in the usual manner. It was claimed that the effect
of this elastic cushion is to impart a gradual movement at the moment of
explosion, which starts the bolt gently from its seat ; the gases then follow
it up and expel it with as much force as the powder is capable of ex-
erting. During the past year, a series of experiments to test this
invention have been made under the direction of the U.' S. Ordnance
Bureau ; the gun employed, in part, being a 130-pounder, filled with
a vulcanized rubber breech-piece, 8 inches in length, .2 of an inch
smaller in diameter than the bore of the gun, with its rear shaped to
fit the bottom of the bore. Its weight was 22 Ibs. The projectile was
a solid shot, weighing 126 Ibs., fired into a bank of earth at 85 feet dis-
tance. The following is the official record of three firings :--"!. Rub-
ber breech-piece was blown out and struck the bank. 2. Rubber
breech-piece started forward 501 inches. While sponging the gun out,
several small pieces of rubber w"ere found. On examining the breech,
found it badly torn. 3. The rubber breech-piece was blown out, and
fell fifty feet to the front of the muzzle of the gun. Finding it so badly
damaged, the trial was discontinued." The results with a 32-pounder
were nearly as unsatisfactory, no increase in the accuracy of fire being
obtained.

Experiments witli Rifled Small Arms. A series of valuable experi-
ments with rifled small arms have lately been conducted by the Ord-
nance Committee of the British Government. Rifles of different
calibers and systems of rifling were tested. As it regards the effect of
the number of grooves in the Enfield rifle, it was found that five were
better than three -- the friction in loading and firing being less and the
shooting more accurate with the five grooves. To test the effect of
the pitch in rifling, two Enfield rifles were tested, the one having a
revolution in sixty-three inches and the other m forty-eight inches, but
both of uniform twist. In calm weather the slow pitch of sixty-three
inches was equal to the other at ranges up to 1,000 yards, but beyond
this it was not so accurate; and in windy weather the more rapid
twist was uniformly more effective at all ranges, but the barrel fouled
more rapidly with the residue of the powder. The caliber of these
rifles is 0.577 of an inch, and they were tried against a Lancaster rifle
of 0.55 inch caliber, elliptical bore, the twist commencing with one
revolution in 36 inches at the breech, increasing to one turn in 33
inches at the muzzle. At all ranges beyond 500 yards the Lancaster
rifle surpassed the Enfield in accuracy, and it^was not so liable to foul.

MECHANICS AND USEFUL ARTS. 67

The same kind of cartridges was used for both rifles. As it respects
the quality of these rifles for army purposes, the report of the Ordnance
Committee is strongly in favor of the Lancaster rifle; the report
sa y S: "Having carefully considered the advantages of the Enfield
and Lancaster systems, ai applied to rifles of large calibers and adapted
to the same ammunition, the committee came to the conclusion that the
Lancaster system has the advantage as regards precision and non-ten-
dency to accumulate fouling, also in simplicity of management^ (a
smooth-bore being more easily cleaned than a grooved one), initial
velocity, and flat trajectory. As it relates to rapidity of fire and cost
of manufacture, the two rifles are about equal."

Experiments were also made with smaller bore rifles, the caliber of
which was .45 of an inch ; the barrels heavier, but stocks lighter than
the Enfield service rifles. Four rifles of this caliber were tested, viz.,
, Whit worth's, with a hexagonal bore and rapid regular twist; Lancas-
ter's, with a smooth elliptical bore and an increasing twist ; Westley
Richard's breech-loader, with a Whitworth barrel ; and an Enfield rifle
of five grooves and regular twist of one turn in forty-three inches. No
less than 1,000 rounds were fired from each rifle without cleaning.
After the seventh round it became difficult to load the Enfield, and be-
fore the conclusion the bullet had to be driven down with a mallet.
The Lancaster did not foul so much, still the mallet had to be used oc-
casionally, but from first to last the Whitworth was loaded with perfect
freedom. As it regards precision, the smaller bore rifles surpassed the
larger bores which were first tried, at all ranges exceeding six hun-
dred yards. The convenience in charging the breech-loader was con-
siderable, and this advantage was fully appreciated.

As the result of these experiments, the Ordnance Committee's
report states that the introduction into the army of a weapon of greater
precision at long ranges would materially increase the efficiency of in-
fantry, and this advantage would be secured in substituting a smaller
bore of rifle for the Eufield service rifle of large bore now in use. But
as the smaller bore rifles wear out faster than those of larger caliber,
their partial introduction into the army only is recommended for the
present. The Whitworth rifle is admitted to have surpassed all the
others for accuracy at long ranges ; but as it requires very peculiar
long cartridges, it was thought these would be inconvenient for army
purposes. The breech-loaders of Westley Richards were recommended
for the cavalry the only apparent obstacle to their introduction for
infantry is their great cost --the price being about fifty dollars each.
The Lancaster system of rifling the barrels is recommended strongly
by the Ordnance Committee to supersede the present method of -rifling
the Enfields, which latter has been copied from the American (Spring-
field) rifles. Scientific American.

Extraordinary Range of Artillery. During the siege of Charleston,
S. C., carried on during the past year by the United States forces un-
der Gen. Q. A. Gilmore, some results have been attained to in artille-
ry practice which are without parallel in the history of warfare. Fort
Sumter, a modern-built, casemated fort, of the best brick masonry,
with walls from six to nine feet in thickness, has been battered into an
irregular heap of ruins and completely destroyed by artillery placed
without elevation on Morris Island, at a distance of 3,500 yards. From

68 ANNUAL OF SCIENTIFIC DISCOVERY.

batteries situated upon the same island projectiles weighing from two
hundred to three hundred pounds have been also sent into the city of
Charleston itself, a distance of ten thousand Jive hundred and sixty
yards (or six miles) and the place successfully bombarded. In 1861,
pending the preliminary operations of -the Confederate army before Fort
Sumter, the question was asked by letter of one of the best authori-
ties in gunnery in this country, whether it would be possible for the
Federal commander of the tort to bombard the city of Charleston
in the event of an attack being made upon him. (The armament of
Fort Sumter at that time consisted of the ordinary smooth-bored thir-
ty-two and twenty-four pounder siege guns, a few eight and ten inch
columbiads, and mortars.) The following was the reply to the inter-
rogatory :

WASHINGTON, Jan. 28, 1861.

Yours of the 25th instant has been received. I am unable to enter
into the reasons on which the opinion is based, but believe that a
bombardment of Charleston from Fort Sumter by any ordnance now
there is out of the question.

Thus it will be seen, that since the commencement of the American
civil Avar in 1861, a most remarkable progress has been made in the
character of the ordnance used in military operations, and results have
been -attained to, which the most sanguine of experts would have hesi-
tated to predict.

English and American Views Respecting Heavy Artillery. The Lon-
don Saturday Review says, " On the question of the best mode of con-
structing heavy artillery, it is possible that we may also have something
to learn from the Americans. All the experiments tried in this country
have pointed at one broad conclusion : that the penetrating power of
a shot depends mainly on the charge of powder, and that it makes com-
paratively little difference whether the powder is utilized by impress-
ing a very high velocity on a moderate-sized bolt, or a lower speed
upon such masses of metal as are hurled from the Dahlgren guns. The
shot, after all, is only a means of carrying the force of the powder from
the cannon's mouth to the target ; and it is not surprising that the re-
sulting effect should depend more on the amount of the original impulse
than on the means employed for its transmission. Still, there must be
certain proportions between the charge and the shot which will pro-
duce the greatest effect; and upon this point English and American
views have long been divergent. Our artillerists have thought more
of increasing velocity, while the Americans have attached the greatest
importance to the bulk of the cannon-ball. It may deserve considera-
tion whether (especially for long-range firing) the Americans have not
come nearer than ourselves to the best model."

The London Army and J\'ary Gazette also in commenting on the
reduction of Fort Sumter by the batteries established by Gen. Gil-
more on Morris Island, at a distance of 3,500 yards, says.

" It may be concluded as certain that the guns used by Gilmore were
Parrot t's rilled ordnance. Their work has been effectually done. Had
such guns been available in the trenches before Sebastopol, the allies
would have made short work, not only of the Iledan and Malakoff, and
bullion <ln mat, but of the shipping and of the forts at the other side of
the harbor. It must not be supposed that Sumter was a flimsy, gin-

MECHANICS AND USEFUL AETS. 69

gerbread fort. It was constructed of a peculiar kind of hard, close
brick, six and seven feet thick ; the arches of the casemates and the
supporting pillars were of eight and nine feet in thickness. The faces
presented" to the breaching batteries must have subtended at 3,500
yards, an exceedingly small angle, and the elevation of the fort was
low. But so great "was the accuracy of the fire that a vast proportion
of the shots struck it ; so great the penetration that the brickwork was
perforated ' like a rotten cheese ; ' so low the trajectory that the shot,
instead of plunging into, passed through the fort, and made clean
breaches through both walls. Now, the guns that did this work cost,
we believe, just one-fourth of our ordnance, cwt. for cwt. ; they are
light and very easily handled. The gun itself is finely rifled, with
grooves varying from four and five in number for small calibers, to six
and seven for the larger ; but, as Mr. Parrott is still ' experimenting,'
no settled plan has been arrived at, and all we know is that the pitch
is not so sharp as is the case in our rifled guns. The projectile is like
the conical Armstrong, and has a leaden sabot and coating, at least
it is coated and based with some soft metal. The Americans have con-
structed cannon of calibers which to us are known only as of theoreti-
cal and probable attainment, and they have armed batteries hundreds
of miles from their arsenals, with the most powerful guns ever used in
war, which have been carried by sea and in stormy waters to the ene-
my's shores. Before such projectiles as these guns carry, the breach-
ing of masonry, whether of brick or stone, is a question of short time.
And, in face of these facts, we are obliged to record that our scientific
officers are of opinion that our ' best gun for breaching purposes is the
old sixty-eight pounder ! ' Why, we know what that can do ! We
know that at 3,500 yards its fire would be about as effectual as that of
Mons Meg. These trials at two hundred yards are perfectly fatuous,
if no other results than these, or such as these, be gained by them. It
is of no use saying Sumter was of brick ; it was at least as good a work
as most of our existing fortifications, and infinitely less easy ' to splinter
up ' than a work of granite or rubble masonry. In substance it resem-
bled very much our martello towers on the beach at Hythe. Have we
any gun which could breach one of these at 3,500 yards? ....
The Authorities have had no experience of the effect of such shot as the
Dahlgrens and Parrotts propel. They have not got the guns to dis-
charge them. When next the ordnance officers and gentlemen meet,
let them apply their minds to the little experiments the Americans
have been making for their benefit at Sumter. It is astounding to see
what progress has been made in artillery since the Crimean war.''

The Material of a Great War. From the report of the U. S. Sec-
retary of War, December 1863, we obtain the following statement of
the amount of war material issued to the armies of the United States
from the commencement of hostilities in April 1SG1, to June 30th,
1863, a period of 26^- months : of siege and sea-coast artillery, 2,088
pieces; of field artillery, 2,481 pieces; firearms for infantry, 1,550,-
576; do. for cavalry, 327,170; sabres, 271,817; cannon-balls and
shells, 1,745,586; lead and lead bullets in pounds, 50,045.515; car-
tridges for artillery, 2,274,490 ; cartridges for small-arms, 378,584,104;
percussion caps, 715,036,470; gunpowder in pounds, 13,071,073; ac-
coutrements for infantry, 1,680,220 sets; do. for. cavalry, 196,298;

70 ANNUAL OF SCIENTIFIC DISCOVERY.

equipments for cavalry horses, 211,670 sets; artillery harnesses,
(double) 1 7,485. And yet, notwithstanding this immense consump-
tion, to which should also be added an immense stock on hand await-
ing requisition and use, the Secretary states, " That the resources of
the country for the production of arms and munitions of war have
only commenced their development. At the beginning of the war,"
he continues, " we were compelled to rely upon foreign countries for
the supply of nearly all our arms and munitions. Now, all these
things are manufactured at home, and we are independent of foreign
countries, not only for the manufacture, but also for the materials of
which they are composed. The excellency of the arms and munitions
of war of American manufacture, which have been supplied by the
Ordnance Department to the army, has been so obvious that our sol-
diers are no longer willing to use those which have been imported from
other countries. ^ The efforts made during the war to extend and improve
the manufacture of arms* and munitions have resulted in discoveries of
great importance to the country, in peace as well as war. Among the
arts thus improved is the manufacture of wrought-iron, now rivalling the
qualities of iron of Sweden, Norway, and England. This country,
until the present year, has relied upon those countries for material to
make gun-barrels, bridle-bits, car-wheel tires and other articles requir-
ing iron of fine quality. Iron of our own production is now superior
to that obtained abroad."

One interesting feature of the military operations of the present
civil war, is the extent to which telegraphic communication has been
resorted to as a means of facilitating and directing operations. It ap-
pears that since the commencement of the war there has been con-
.structed, and is now in operation, 5,326 miles of land and submarine
military telegraph ; a length sufficient to girdle more than one-fifth
of the circumference of the globe. Over these lines there were sent
during the year, ending June 30th, 1863, at least 1,200,000 telegrams,
varying in length from ten to one thousand words.

IRON-CLAD SHIPS AND BATTERIES.

Number and Strength of the American Iron- Clad Fleet. From the
report of the Secretary of the Navy, communicated to Congress, De-
cember 1863, it would appear that the U. S. Government is now in
possession of a larger number of iron-clad steamers than any other na-
val power. The whole number afloat, or approaching completion, is
seventy-five; of which forty-six, carrying 150 guns, and having an ag-
gregate tonnage of 62,513, are intended for coast service ; and twenty-
nine, carrying 152 guns and a tonnage of 20,784, are for inland service.
Of the iron-clads launched during the past year, or now in the pro-
cess of construction, the following are especially worthy of nottce :

The Onondaga is an iron-turreted steamer, though not of the Erics-
son (monitor) model, but was built after a design furnished by her
constructor, Mr. George Quintard, of New York. She is constructed
wholly of iron. The hull is 226 feet in length and forty-eight feet in
width. The frames are of angle-iron five inches by three, riveted to
a central plate at the bottom. There is no keel, properly speaking,
but a ribbed or arched plating in the place of it, to which all the

MECHANICS AND USEFUL ARTS. 71

frames are joined. There are no projecting armor shelves on the
sides, but the vessel is protected from shot by single plates four and a
half inches in thickness with the additional protection of a layer of
nine-inch locust and three-inch oak timber, covered again with two-
inch solid plates of iron, thus making the mail in reality 18^ inches
thick, 6 of which are iron. The draught of the ship will be ten feet.

There are two propellers or screws, one on each side under the
stern, each propeller being driven by two engines. The turrets are
the same as those upon all the monitors ; eleven inches thick in the
walls, nine feet high and twenty-one feet in diameter inside. There
are two fifteen-inch guns in each turret. Neither the bow nor stern of
the Onondaga overhangs the hull, the stern projecting only enough to
cover the screws and protect them from damage by shot. There are
thirteen transverse water-tight compartments, and the coal bunkers
surround the boilers in addition to the protection afforded by the iron
plating.

The .Dictator. This name has been given to an iron-clad war-ship
constructed during the past year in New York, from designs by Erics-
son, based on the principles of the first monitor, but superior, so far as
relates to size, speed, sea-worthiness, and impenetrability, to any armor-
clad vessel hitherto constructed in the United States. The following-
statement of the points and dimensions involved in her construction we
copy from the Scientific American : u The extreme length of the
vessel over all, is 314 feet ; its aft overhang being thirty-one feet, and
forward overhang thirteen, leaving 260 feet between perpendiculars ;
extreme breadth fifty, and depth 22^ feet. The hull, in sides and
frame, is constructed of iron. The armor shelf extends outside of the
hull four feet on each side, and is prodigiously strong. Some idea of
its impenetrable character will be derived from the following account
of its construction. The outside is covered with six one-inch plates of
iron fastened in the most substantial manner, and inside of this are
three feet of oak timber and an armor lining formed of 4J inch bars
extending all around. The armor shelf therefore consists of 10^ inches
in thickness of iron, and three feet of timber, and between the metal
and timber is interspersed a thick layer of felting. No gun yet fabri-
cated can project a shot that will pierce this armor-jacket.

The keel-plate of the Dictator is of one-inch plate, the side plates -|th
inch, and the frame of Double angle-iron, six by four inches. The in-
terior is divided into several water-tight compartments by plate bulk-
heads, and the space forward of the third bulk-head below will be used
for coal bunkers, through the middle of which will be a railway to
carry the fuel to the boilers. The deck beams are of kyanized oak.
Two engines, each having a cylinder of one hundred inches in diame-
ter and four feet stroke, will be employed to drive the screw, which is
four-bladed, 21|- feet in diameter, and of thirty-four feet pitch. Six
boilers, capable "of furnishing 5000 horse-power to the engines, supply
the motive force. The boilers have fifty-six furnaces and an aggregate
grate surface of 1,000,100 feet ; and allowing twelve pounds of coal
per square foot of grate surface, the vessel will require, at the least, 175
tons of coal per day of twenty-four hours, steaming at full speed.

As the Dictator is furnished with a strong bow, its speecf, strength,
and mass will render it a must eiiicieut marine rani. . It is provided

7-2

ANNUAL OF SCIENTIFIC DISCOVERY.

with one revolving turret, capable of carrying two heavy guns, which
is believed to be impenetrable against any projectile hitherto experi-
mented with. The following are its dimensions. The diameter of the
inside turret is twenty-four feet. The turret itself being formed of six
thicknesses of inch-plate riveted together. Over and outside of this is
another turret forming a sleeve, consisting of seven thicknesses of inch-
plates riveted, while between the two are additional shields of iron
hoops or bars, having an aggregate of five inches ; so that the whole
forms one great revolving iron tower eighteen inches in thickness,
twenty-seven feet in diameter, and weighing about two hundred tons.
A companion vessel to the Dictator, named the Puritan is also in the
course of construction.

The Dunderberg.- -This name has been given to a vessel now in the
course of construction, at New York, which combines the features of a
ram and an iron-clad monitor. Her length is 378 feet, width sixty-
eight feet, and depth of hold thirty-two feet. The model is peculiar ;
the floor is dead flat, at an angle with the sides, except at the forward
end, where it is nearly vertical. The hull is divided into water-tight
compartments. The sides below the main deck are 6-1 feet thick, and
on the casemates there are three feet of solid timber firmly bolted.
The iron plating is 4-1 inches thick on the sides and 3-1 inches on the
casemate. This vessel is 7000 tons burthen. Her deck is bomb-
proof, and she will be rigged half-mast with yards and sails, which will
enable her to cruise without the aid of her engines.

The whole forward part of the vessel, for a distance of fifty feet, is
solid wood-work, covered on the sides and edge with the iron armor,
constituting the ram, which has the profile of an axe edge. Should
this ram be knocked away, which is improbable, the hull will still re-
main water-tight. The engines are of 6,000 horse-power.

The Dunderberg is to be furnished with two revolving turrets, twen-
ty-one feet in diameter inside, and nine feet high, placed fore and aft.
The hull is pierced for three broadside guns on each side, as well as
one fore and one aft for bow and stern chasers. The draught of water
of the Dunderberg when loaded will be twenty-one feet.

New Iron-Clads of the Monitor pattern. The iron-clad turreted
vessels, of the so-called Monitor* pattern, introduced by Ericsson,
having proved eminently efficient and suitable for harbor attack and
defence, the U. S. Navy Department has continued their construction,
and has already a large fleet of them afloat, or on the stocks. Al-
though in the chief points of their structure there is great similarity
between the new vessels and the original Monitor, there is neverthe-
less a considerable difference in their details, which, as showing a prog-
ress in this department of naval architecture, is worthy of notice.
The following table shows the peculiarities of the original Monitor ;
of the Passaic, one of a second series of nine built subsequently ; and
of the Tecumseh, one of a third series of nine, built during the past
year (1863.)

Original Monitor. Passaic. Tecumseh.

190 ft. 200 ft. 235 ft.

Length

Width
Depth of hold

Draft of water
Armor of sides
Thickness of turret

30 "

9 "

9 "

4| in.
11 "

40 "
91 "

10 "
4 in.

11 "

4G "
14 "
14 "
9 in.
11 "

MECHANICS AND USEFUL ARTS. 73

Original Monitor. Tassaic. Tecumseh.

Diameter of turret . 21 ft. . 21 ft. ... 21 ft.

Number of turrets .1 . .

Dimensions of cylinders 30 in. .
Armament . . 2 11-in.guns.

Tonnage . . 800

1 ... 1

35 in. . . . 40 in.
11 and 15-in. guns. 2 13-in. guns.
. . 1,400

It will be observed that the most important differences between the
power of the first Monitor and the Tecumseh consist in the armor and
armament the offensive and defensive attributes. Instead of four
and one-half inches we have nine inches of iron, and instead of one
eleven and one fifteen-inch guns, the Tecumseh will have two thir-
teen-inch guns, which, however, will be able to burn more powder
than the old fifteen-inch guns. It was impossible when adding more
weight of armor to the ship to make the draft of water as light as in
the "Monitor, if that were even desirable, which is a matter not decided
on. One of the peculiarities of the Tecumseh is this, that she has
sponsons which tighten the frame to the vessel, as it were. In the
original Monitor this sponson was left out, and the consequence was
that the overhang was said to have been the cause of the loss of that
celebrated little vessel.

The accident that happened to one of the monitors during Dupont's
attack on Charleston, which resulted in the temporary crippling of
the turret, cannot happen to the Tecumseh, because an immense band
of iron, several inches thick, perfectly solid and massive, covers the
whole external base o-f the turret, rendering it absolutely impossible
for any shot or shell to pierce it. This will insure the freedom of the
turret, so far as its revolving powers are concerned. The propeller is
driven by two powerful engines, with cylinders of forty inches in di-
ameter and twenty-eight inch stroke of piston ; and it will be observed
that the speed of the Tecumseh w^ll, in the natural course of things, be
much greater than that of the original monitors, as the dimensions of
her cylinders are nearly ten inches greater than those of the other
ships. The monitors of the Passaic series have not realized the speed
expected of them, but it is hoped that the Tecumseh series will do "
better.

In still less important matters there are some points of difference ;
in keeping the anchor, for instance, an arrangement is now made by
which two holes are placed on each side of the bow, while in the other
monitors it was directly in the centre. In fastening, the armor-rivets
are substituted for bolts, as the latter give way and fly about when
struck by heavy projectiles "in a severe engagement. In the arrange-
ment of the machinery, the air and circulating pumps and the surface-
condensers are independent of the main engines, and can thus be op-
erated when the main engines are standing still, maintaining constant-
ly a vacuum, and being able to keep up the condensation of steam, in-
stead of blowing it off into the atmosphere, which every naval officer
will appreciate, because it has been one of the most Intolerable nui-
sances of the introduction of steam in the navy that when orders are
given upon the deck the blowing of the steam rendered them inaudible,
and it could not be silenced without danger of boiler explosions.

New pattern Monitors. - - Several vessels of the Monitor pattern,
buildino- in Boston, and intended for the defence of Massachusetts har-

^^

bors, have some marked differences of construction from the monitors

7

74 ANNUAL OF SCIENTIFIC DISCOVERY.

described above, and constructed for the U. S. Navy. These peculiar-
ities or improvements are thus described in the Boston Herald : " One
of them is a water-tight compartment two feet in width, extending
around the whole body of the vessel. The water is pumped out of this
compartment when the monitor is at sea. This lightens her, and, hav-
ing less surface exposed to the water, she can move more rapidly. If
the monitor is preparing for action, the compartment is filled. This
sinks her deeper into the water, so that little of the vessel, if any, ex-
cepting the turret, is visible. Outside of the water-tight division is to
be four feet of wood, and outside of the wood five inches of iron-plate.
To obviate the foul bottoms to which iron ships are liable, an oak bot-
tom is to be bolted on the iron one, and to be coppered like those of or-
dinary wooden vessels. They carry propellers and are provided with
two screws, one under each counter, by which they can be turned in a
smaller circle and in much less time than by a single screw."

The Comanche. This vessel is one of the Ericsson monitors, and the
circumstance particularly noticeable about her is, that she was con-
structed in Jersey City, N. J., put together perfectly upon the stocks ;
and then taken apart and conveyed to San Francisco, California, where
she will be reconstructed. This feat of taking apart a ship of the size of
the Comanche (200 feet) has never been attempted before, and was emi-
nently successful in this case, every bolt being put in its place before a
single particle of the hull was taken down. The armor-plating of the
Comanche is composed of five courses of plates, having an aggregate of
five inches thickness.

Sheathing for Iron-dads. - - Some very interesting practical experi-
ence has lately been gained in England in the use of paints for iron-
clad vessels ; also in the use of brass sheathing to prevent their bottoms
from becoming foul. The large armor-frigate, Black Prince, after
having; been five months in the water, was recently docked at Devon-

c? '

port and her bottom examined. It had been coated on one side with
a paint chiefly composed of oxide of copper, and on the other with one
partly composed of the sulphate of copper. Both sides were corroded,
but the sulphate of copper was the cleanest ; still there were thousands
of barnacles adhering to the plates on both sides. The Resistance,
another smaller armor-frigate, was docked at the same time, but it had
not been in service quite so long. One of its sides had been covered*
with the oxide of copper paint, and the other with another paint, the
composition of which has not been published ; along the bottom also
several patches had been covered with thin porcelain plates cemented
with marine glue. It was found that most of these plates had dropped
off, the glue not being capable of holding them, and the rest of the bot-
tom was nearly as foul as that of the Black Prince. But the most re-
markable case was that of the Royal Oak, which was also docked at
the same time. This was a wooden vessel which had been originally
designed for a line-of-battle ship, but was afterwards plated with iron.
A band of lead was then run around the whole vessel below the deep-
load line, below which the vessel was sheathed with Muntz metal,
the common brass sheathing, containing about sixty per cent, of copper
to forty of zinc. The iron plates were painted with red lead ; and it
was supposed that the intermediate lead band, coated with paint,
would prevent contact and galvanic action between the iron and the

MECHANICS AND USEFUL ARTS. 75

sheathing. The latter was perfectly clean, but astonishment was
caused by the galvanic action which had been induced between the
iron and the sheathing. The lower tier of iron plates each fifteen
feet in length, three feet two inches in breadth, and four and one-half
inches in thickness were perfectly honey-combed, the holes varying in
depth from one-fourth to five-eighths of an inch. Judging from the rate
at which the corrosion had proceeded, the plates would have been entire-
ly dissolved, had the vessel remained in the water many months longer.
It had been supposed that wooden vessels could be built with iron plat-
ing descending below the water-line, and that their bottoms could be
sheathed with copper, and thus remain as clean as copper-bottomed
wooden vessels. Indeed, this very mode of constructing war vessels
has been advocated by a French naval architect as being superior to
all others, and several French and Italian arnior-clads have been built
upon such ideas. The practical and expensive experiment made with
the Royal Oak affords us evidence that copper, or copper alloys, can-
not be employed with safety connected by sea-water with iron on a
vessel. The connection of these two metals forms a galvanic battery
leading to the rapid .decomposition of the positive metal. Scientific
American.

Conflict between the WeeJiawken (Monitor) and Atlanta, Iron-Clach.
Some important information respecting the offensive and defensive
powers of iron-clad vessels and their improved armaments has been
derived during the past year from the conflict between the Weehawken,
one of Ericsson's monitor iron-clad vessels, and the iron-clad Con-
federate steamer Atlanta, which resulted in the surrender of the latter.
The Atlanta was originally a sea-going steamer, the Fingal, re-
modelled and iron-plated. Her armor is described as follows : First
and on the outside were wrought-iron bars, six inches wide by two
inches thick, running perpendicularly with her side, and proper-
ly secured, both above and below, by rivets and bolts. Across these
bars, horizontally, and on the inside, ran bars of like material and pat-
tern, fastened to the outside layer by the strongest rivets. Within this
layer, and fastened to it, were two thicknesses of live oak two-inch
plank, also running perpendicularly and horizontally, and again, within
these, were two more similar thicknesses of Georgia pine plank, form-
ing the last series of her armor. The thickness of the Atlanta's armor,
therefore, was twelve inches, four of iron, four of live oak, and four
of pine planking. Her pilot-house is also thus described : Forward .
of the snioke-stack was an elevation on the top deck, to all appearance
like a cone ; upon this cone was a small, square lookout, just large
enough on the inside to allow a man's head to turn with freedom. On
each side of this lookout were two small apertures, in the shape of
parallelograms, slanting toward the interior, and presenting to the pi-
lot's optics, in the lookout, two lookouts, an inch and a half long by an
inch wide. This look-out was of wrought iron, four inches thick, and
the cone upon which it stood was the same thickness, with this addi-
tional strength, however, that the interior of the pilot-house being
square, the interstices between the sides of the upper part of the pilot-
house and the concave surface of the cone were filled with eight-inch,

^

square, live-oak blocks. From the top of the lookout to the base of
the cone was but two feet and a half.

76 ANNUAL OF SCIENTIFIC DISCOVERY.

The action commenced by the Atlanta firing three shots. The Wce-
hawken then replied with her fifteen-inch gun, throwing a solid shot of
440 pounds ; and the first shot virtually decided the action, for the ter-
rible missile tore through the Atlanta's iron-plating and timber-backing,
as if it were stubble, and prostrated about forty of her crew, some by
splinters, but the most part by the mere concussion.

The second shot struck one of the Atlanta's port-stoppers, which
were protected by four inches of wrought iron, knocking it into
fragments, and wounding seventeen men. The third shot smashed the
top of the pilot-house, wounding two of the pilots, and stunned the
two men at the wheel, prostrating the whole four on the floor of the
pilot-house. The fourth shot struck her on the knuckle, that is, where
the iron casemate joins at a sharp angle the iron plating of the side ; and
the fifth shot went through her smoke-stack. After the fifth shot, the
Atlanta surrendered ; the whole action, from the firing of the first gun,
being over in fifteen minutes. The U. S. Secretary of the Navy, in
commenting on this engagement in his report to Congress, Dec. 1863,
says : " This battle was to test not only the vessels but the new fif-
teen-inch ordnance, then for the first time brought into naval warfare,
and concerning which there had been, as well as with respect to the
vessels themselves, some variety of opinion. The conflict was so brief
and decisive that only one of the two monitor vessels present, though
not widely separated, and each eager for the fight, was able to par-
ticipate in the engagement. The Nahant, having no pilot, followed in
the wake of the Weeliawken, but before she could get into action the
contest was over. Such was the brevity of the fight that the Weeliaw-
ken, in about fifteen minutes, and with only five shots from her heavy
guns, overpowered and captured her formidable antagonist before the
Nalmnt, which was hastening to the work, could discharge a single
shot at the Atlanta. This remarkable result was an additional testi-
mony in favor of the monitor class of vessels for harbor defence and
coast service against any naval vessels that have been or are likely to
be constructed to visit our shores."

Oilier trials of Iron-Clads in Action. But the most severe and practi-
cal test to which iron-clad vessels have as yet been subjected occurred
on the 7th of April, 1863, in the attack made by the U. S. fleet upon
the forts and earthworks commanding the harbor of Charleston, S. C.
On that occasion nine iron-clads, - - including seven vessels of the
JVlonitor pattern, the Ironsides, an iron-clad broadside steamer, and
the Keokuk, an iron-clad of a peculiar and novel construction, (see
Annual of Sci. Dis. 1863, p. 63), taking a position where they
were exposed, at comparatively short range, to the concentric and
cross-fire of two regularly-constructed forts, and some half-dozen earth-
works mounting heavy, and in part rifled ordnance, assailed Fort
Sumter, a fortress of modern construction and of great strength. The
result was, that after a contest of a little less than two hours, in which
the vessels engaged sustained the most fearful and concentrated fire on
record, the'forts and batteries using the heaviest and most improved
projectiles (including the Armstrong and Whitworth patterns),
the fleet was withdrawn. Upon the monitors and the Ironsides, al-
though all these vessels were struck repeatedly (the Ironsides alone some
ninety times) no person was killed, or even seriously injured ; while the

MECHANICS AND USEFUL ARTS. 77

efficiency of these vessels was not permanently impaired : the most se-
rious injury, perhaps, occurred to the Passaic (monitor), which was
disabled by being struck at the base of its turret by a heavy shot, which
so jammed the contiguous plating as to prevent the tower from rotating.
The Keokuk, however, was more unfortunate. This vessel was smaller
than any of the monitors engaged, being plated with one and three-
fourths-inch plates on a four-inch backing of iron and wood ; the plates
being inclined at an angle which, amidships, was equal to 36, with a
view of deflecting shot striking against them. The unfitness of such
armor for defensive purposes was illustrated in a very few minutes af-
ter the Keokuk came under fire. The armor was riddled with shot in
every direction ; a considerable number of her crew were wounded, and
one killed, while the vessel herself sunk some twelve hours after the
conclusion of the fight. 1

The Ironsides, a non-turreted broadside steamer, plated with four
and one-half inch solid armor, backed by from twenty-four to thirty inches
of oak, which took part in the above noticed attack, and in several
other subsequent actions, appears to be the most effective and in-
vulnerable of all the iron-plated vessels as yet constructed and sent in-
to service by the United States ; some even claiming that she is equiv-
alent to any six vessels of the monitor pattern. In "the various actions
in Charleston Harbor in which the Ironsides participated, from April
to September, she is reported to have been struck by shot and shell,
two hundred and thirteen times, none of which have caused serious in-
jury to life or limb of her crew, or essentially injured the vessel. The
water-line of the Ironsides alone bears the imprint of ten ten-inch
solid shot, while the most serious damage resulted from two shots strik-
ing the same plate, within a foot of each other, and within a foot of
the end of the plate. The result was the partial cracking of the
plate, bending it, and forcing it about an inch into the wood-work. It
occasioned no leak in the vessel. Several ten-inch solid shot, and one
eleven-inch, have passed through the unprotected part of the bow and
stern ; but so much of their momentum was lost in the passage, that
they did not reach the wrought-iron bulkheads that cross the ship for-
ward and aft, and which would have effectually stopped their further
progress.

The method of fastening the plating to the sides of the Ironsides has
proved very effective. It consists of common wood-screws, put through
the plates from the outside, and tapped into the wood, having cylin-

'All vessels with inclined armor are supposed to be so constructed that the shot
will glance from them without doing any damage. If we conclude, for the purpose
of argument, that the enemy will fire a round shot at a very low velocity, on a line
with the horizon, then the assumption may be correct. The fact of the matter is,
however, that inclined sides simply present to barbette guns the fairest target they
could desire, and the supposed efficiency of the angle is utterly neutralized. The
Galena, at Drury's Bluff, and other gunboats on the western rivers, which were
constructed with inclined armor, have been repeatedly pierced by guns fired from
elevations. Inclining the armor simply increases the thickness of the plating to
be pierced when the shot is fired on a line with the horizon. A plunging fire is re-
ceived by inclined plating fair and square, and there are no instances on record
where acutely-inclined armor has resisted the impact of the heaviest rifled shot at a
fair range. The Parrott 300-pounder'is said to have pierced nine inches of iron
inclined at an angle of 45, and the Stafford projectile is known to have penetrated
seven one-inch plates, heavily backed up with timber, at the same inclination. In-
clined sides, with inadequate armor, are simply a delusion and a snare. Scientific
American.

1*

78 ANNUAL OF SCIENTIFIC DISCOVERY.

drical heads countersunk into the plating and flush with the outside.
Several of these screw-bolts have been struck directly on the head with-
out causing any damage ; whereas, if the ordinary plan of using through
bolts or rivets had been adopted, it is very probable that some persons
would have been injured by fragments of the bolts being projected
inside the ship. In the case of the monitors, the most serious acci-
dents that have occurred on board them have arisen from the displace-
ment and breaking of the bolts that hold together the plates of their
turrets, through the impact of heavy shot. An idea of the fighting
capabilities of the Ironsides may be formed from the circumstance that
she threw, in the various attacks in which she participated from April
to September, upwards of 4,400 shells.

It is understood that one result of the attack on the fortifications of
Charleston, by the U. S. iron-clad fleet, has been the withdrawal from
the monitors of the fifteen-inch guns, with which their turrets were
armed, and the substitution of thirteen-inch guns in place.

New Port-Closer for Vessels of War. An ingenious device for
closing the ports of iron-clads and other vessels of war has recently
been patented by Mr. W. S. Auchincloss, of New York City. The
nature of the invention will be readily understood from the following
clause of the patent : The employment or use for a port-hole closer
of two rollers, each being made to rotate independently of the other,
and provided with a cavity, so that by turning the rollers to the proper
position an opening is obtained which allows of giving to the gun any-
desired elevation, or of training the same to an angle of 45 or more.

NATURAL PHILOSOPHY.

THE PHILOSOPHY OF TO-DAY.

" THE natural philosopher of to-day may dwell amid conceptions
which beggar those of Milton. So great and grand are they, that in
the contemplation of them a certain force of character is requisite to
preserve us from bewilderment. Look at the integral energies of our
world ; the stored power of our coal-fields, our winds and rivers, our
fleets, armies, and guns. What are they? They are all generated by
a portion of the sun's energy, which does jiot amount to- 2)3 Q ;-Q^ 0>000 '
of the whole ! This, in fact, is the entire portion of the sun's force in-
tercepted by the earth, and in reality we convert but a small portion
of this fraction into mechanical energy. Multiplying all our powers
by millions of millions, we do not reach the sun's expenditure. And
still, notwithstanding this enormous drain, in the lapse of human his-
tory, we are unable to detect a diminution of his store. Measured by
our largest terrestrial standards, such a reservoir of power is infinite ;
but it is our privilege to rise above these standards, and to regard the
sun himself as a speck in infinite extension ; a mere drop in the uni-
versal sea. We analyze the space in which he is immersed, and which
is the vehicle of his power. We pass to other systems and other suns,
each pouring forth energy like our own, but still without infringement
of the law, which reveals immutability in the midst of change, which
recognizes incessant transference and conversion, but neither find gain
nor loss. This law generalizes the aphorism of Solomon, that there is
nothing new under the sun, by teaching us to detect everywhere, un-

O ' / c5 /

der its infinite variety of appearances, the same primeval force. To
nature nothing can be added ; from nature nothing can be taken
away ; the source of her energies is constant, and the utmost man can
do, in the pursuit of physical truth, or in the application of physical
knowledge, is to shift the constituents of the never-varying total, and
out of one of them to form another. The law of conservation rigidly
excludes both creation and annihilation. Waves may change to rip-
ples, and ripples to waves; magnitude may be substituted for number,
and number for magnitude; asteroids may aggregate tio suns, suns
may revolve themselves into florae and faun SB and floras and faunae
melt in air ; the flux of power is eternally the same. It rolls in music
through the asjes, and all terrestrial enerer, the manifestations of life,

C- ** /

as well as the display of phenomena, are but the modulations of its
rhythm." Prof Tyndall.

THE NATURE OF FORCE.

The following is an extract of a lecture recently delivered before
the Royal Institution, London, by Prof. Tyndall, on the above subject.

79

80 ANNUAL OF SCIENTIFIC DISCOVERT.

" Standing upon one of the London bridges, we observe the current
of the Thames reversed, and the water poured upwards twice a day.
The water thus moved rubs against the river's bed and sides, and heat
is the consequence of this friction. The heat thus generated is in part
radiated into space, and then lost, as far as the earth is concerned.
What is it that supplies this incessant loss? The earth's rotation. Let
us look a little more closely at the matter. Imagine the moon fixed,
and the earth turning like a wheel from west to east in its diurnal ro-
tation. Suppose a high mountain on the earth's surface ; on approach-
ing the moon's meridian, that mountain is, as it were, laid hold of by
the moon, and forms a kind of handle by which the earth is pulled
more quickly round. But when the meridian is passed, the pull of the
moon on the mountain would be in the opposite direction; it now
tends to diminish the velocity of rotation as much as it previously auo 1 -
mented it ; and thus the action of all fixed bodies on the earth's sur-
face is neutralized. But suppose the mountain to lie always to the
east of the moon's meridian, the pull then would be always exerted,
against the earth's rotation, 'the velocity of which would be diminished
in a degree corresponding to the strength of the pull. The tidal-wave
occupies this position ; it lies always to the east of the moon's meridian,
and thus the waters of the ocean are in part dragged as a brake along
the surface of the earth ; and as a brake they must diminish the veloc-
ity of the earth's rotation. The diminution, though inevitable, is, how-
ever, too small to make itself felt within the period over which obser-
vations on the subject extend. Supposing then that we turn a mill by
the action of the tide, and produce heat by the friction of the mill-
stones; that heat has an origin totally different from the heat produced
by another mill which is turned by a mountain stream. The former is
produced at the expense of the earth's rotation, the latter at the ex-
pense of the sun's radiation.

" The sun, by the act of vaporization, lifts mechanically all the mois-
ture of our air. It condenses and falls in the form of rain ; it freezes
and falls as snow. In this solid form, it is piled upon the Alpine
heights, and furnishes materials for the glacieys of the Alps. But
the sun again interposes, liberates the solidified liquid and permits
it to roll by gravity to the sea. The mechanical force of every river
in the world, as it rolls toward the ocean, is drawn from the heat of
the sun. No streamlet glides to a lower level, without having been
first lifted to the elevation from which it springs by the mighty
power of the sun. The energy of winds is also due entirely to the,
sun ; but there is still another work which he performs, and his con-
nection with which is not so obvious. Trees and vegetables grow upon
the earth, and when burned they give rise to heat, and hence to me-
chanical energy. Whence is this power derived ? You see this oxide
of iron, produced by the falling together of the atoms of iron and ox-
ygen ; here also is a transparent gas which you cannot now see, car-
bonic acid gas, which is formed by the falling together of carbon
and oxygon. These atoms thus in close union resemble our lead
weight Avhile resting on the earth ; but I can wind up the weight and
prepare it for another fall, and so these atoms can be wound up, sepa-
rated from each other, and thus enabled to repeat the process of com-
bination. In the building of plants, carbonic acid is the material from

NATURAL PHILOSOPHY. 81

which the carbon of the plant is derived ; and the solar beam is the
agent which tears the atoms asunder, setting the oxygen free, and
allowing the carbon to aggregate in woody fibre. Let the solar rays
fall upon a surface of sand ; the sand is heated, and finally radiates
away as much heat as it receives ; let the same beams fall upon a for-
est, the quantity of heat given back is less than the forest receives, for
the energy of a portion of the sunbeams is invested in building up the
trees in the manner indicated. "\Yithout the sun the reduction of the
carbonic acid cannot be effected, and an amount of sunlight is con-
sumed exactly equivalent to the molecular work done. Thus trees
are formed ; thus cotton is formed. I ignite this cotton and it flames ;
the oxygen again unites with its beloved carbon ; but an amount of
heat equal to "that which you see produced by its combustion was sacri-
ficed by the sun to form that bit of cotton.

" But we cannot stop at vegetable life, for this is the source, mediate
or immediate, "of all animal life. The sun severs the carbon from its
oxygen ; the animal consumes the vegetable thus formed, and in its ar-
teries a reunion of the several elements takes place, and produces ani-
mal heat. Thus, strictly speaking, the process of building a vegetable
is one of winding up ; the process of building an animal is one of run-
ning down. The warmth of our bodies, and every mechanical energy
which we exert, trace their lineage directly to the sun. The fight of a
pair of pugilists, the motion of an army, or the lifting of his own body
up mountain slopes by an Alpine climber, are all cases of mechanical
energy drawn from the sun. Not, therefore, in a poetical, but in a
purely mechanical sense, are we children of the sun. Without food,
we should soon oxidize our own bodies. A man weighing 150 pounds
has sixty-four pounds of muscle ; but these, when dried, reduce them-
selves to fifteen pounds. Doing an ordinary day's work for eighty
days, this mass of muscle would be wholly oxidized. Special organs
which do more work would be more quickly oxidized ; the heart, for
example, if entirely unsustained, would be oxidized in about a week.
Take the amount of heat due to the direct oxidation of a given
amount of food ; a less amount of heat is developed by this food, in
the working animal frame, and the missing quantity is the exact equiv-
alent of the mechanical work which the body accomplishes.

" I might extend these considerations, the work, indeed, is done to
my hand, but I am warned that I have kept you already too long.
To whom then, are we indebted for the striking generalizations of this
discourse ? All that I have laid before you is the work of a man of
whom you have scarcely ever heard. All that I have brought before
you has been taken from the labors of a German physician, named
Mayer. Without external stimulus, and pursuing his profession as
town physician in Heilbronn, this man was the first to raise the con-
ception of the interaction of natural forces to clearness in his own
mind. And yet he is scarcely ever heard of in scientific lectures, and
even to scientific men his merits are but partially known. -Led by his
own beautiful researches, and quite independent of Mayer, Mr. Joule
published his first paper on the ' Mechanical Value of Heat' in 1843;
but in 1842 Mayer had actually calculated the mechanical equivalent
of heat from data which a man of rare originality alone could turn to
account. From the velocity of sound in air, Mayer determined the

82 ANNUAL OF SCIENTIFIC DISCOVERY.

mechanical equivalent of heat. In 1845, he published his Memoir on
4 Organic Motion,' and applied the mechanical theory of heat in the
most fearless and precise manner to vital processes. He also embraced
the other natural agents in his chain of conservation.

" When we consider the circumstances of Mayer's life, and the pe-
riod at which he wrote, we cannot fail to be struck with astonishment
at what he has accomplished. Here was a man of genius working in
silence, animated solely by a love o/ his subject, and arriving at the
most important results some time in advance of those whose lives were
entirely devoted to Natural Philosophy. It was the accident of bleed-
ing a feverish patient at Java, in 1840, that led Mayer to speculate on
these subjects. He noticed that the venous blood in the tropics was
of a much brighter red than in colder latitudes, and his reasoning on
this fact led him into the laboratory of natural forces, where he has
worked with such signal ability and success. Well, you will desire to
know what has become of this man. His mind gave way ; he became
insane, and he was sent to a lunatic asylum. In a biographical dic-
tionary of his country it is stated that he died there ; but this is incor-
rect. He recovered, and, I believe, is at this moment a cultivator of
vineyards in Heilbronn."

EFFECTS OF THE EARTH'S ROTATION.

M. Foucault's beautiful experiment, by which, through the medium
of a pendulum, the rotation of the earth on its axis may be said to have
been rendered palpable to our senses, has had the effect of calling at-
tention to a great many other phenomena going on on its surface, into
which it enters as a modifying cause. To say nothing of those great and
general facts of the oblateness of its figure, and the trade-winds which
Newton and Hadley explained on this principle, we have seen the
phenomena of Cyclones reduced to a dependence on this cause, com-
bined with local disturbances of temperature ; and, tracing the same
cause into its still more local, and, so to speak, miniature sphere of action,
it is recognized that the influence of the earth's rotation cannot be left
out of consideration in the accurate pointing of long-range artillery,
inasmuch as in a flight of five miles, occupying twenty -five seconds of
time, it would carry a projectile pointed northwards, about forty-five
feet to the east, and southwards as much to the west, (. e. in both cases
toward the right hand) of its line of fire. Pursuing the action of this
cause into geographical inquiries, it has been argued that the action of
a river flowing directly northwards or southwards, or indeed in any
direction considerably inclined to the parallel, cannot be equal on its
right and left banks ; and that in either case (and indeed, whatever
be the direction of the stream, if at all so inclined), in the northern
hemisphere, the rotatory motion of the earth will have the effect of
driving the water against the right bank of the river, and thus causing
it to exert a greater erosive action on that than on the opposite side ;
and vice versa in the southern hemisphere ; the effect in both being
more powerful the higher the latitude ; and nil on the equator. On
the other hand, it has been contended, that although, theoretically
speaking, this is a real cause, (a vera causa), yet the amount of ero-
sion thence arising must be far too small to produce any sensible ten-
dency in rivers to shift their courses to the right, or to eat away

NATURAL PHILOSOPHY. 83

their right banks perceptibly more than their left ; and this opinion
seems to have found currency among the French academicians, when-
ever the subject has been discussed at the meeting of the Institute.

Regarding this question as one of fact rather than of opinion, M.
Von Baer, in an elaborate memoir, read before the Imperial Academy
of St. Petersburg, and lately published in the bulletins of that body,
has brought together so large a mass of instances, drawn from observa-
tion of the courses of almost all the rivers of any note, both in Euro-
pean and Asiatic Russia as to justify this enumeration as a general feature
(not of course, without local exceptions, owing to the natural inequalities
of ground), over the whole of that vast region, that the right bank of a
river is higher and steeper ; the left the flatter and more alluvial one,
and more subject to inundation, the law being so general, that over
vast tracts of country, it may be predicted, almost without risk of fail-
ure, from the aspect of a stream in this respect, in which direction it
runs. It deserves remark, that this general tendency has already been
noticed by more than one geologist of eminence, without any suspicion ^
of its cause. Thus, even so long ago as 1847, Major Waugenheim von
Qualen had announced it as a general feature of the Russian River
system, in the bulletins of the Society of Naturalists of Moscow ; and
besides giving the result of his own observations in the region to
the south and west of the Ural (where, from the absence of any con-
siderable mountain system, and the general flatness of the country, the
action of this cause would be little liable to be masked by local in-
equalities of a geological origin), cites the authority of M. Blode, as
having observed the same thing in southern, M. Bouiller in central,
and Baron Wrangell in northern Russia ; Tschichatscheff, in central
Siberia ; and Blasins, and other geologists, in many other parts of Rus-
sia, adding that a feature so uniform, and prevailing over so vast an
extent of territory, must evidently be due to some uniform and general
cause. This cause he seeks, accordingly, in geological upheavals and
dislocations, though evidently at a loss to perceive how such upheavals
should have affected always the right bank of the river, without regard
to the point of the compass toward which the water flows.

The same cause which throws the water of a river preferentially against
its right bank must act of course in every case where masses of matter
are in motion along definite lines of route, and therefore on railways,
wherever there is a double line of rail for up and down traffic. For in
such the right-hand rail on each line will be most worn ; and, in all cases,
the flanges of the right-hand wheels of the carriages will suffer most
by abrasion, and a greater probability (though in a very slight ratio)
will exist of running off the rail to the right than to the left side of the
line of travel, especially in lines running due north and south.

CURIOUS DEVIATIONS OF THE PLUMB-LESTE.

The deviations of the plumb-line at different points of the earth's
surface from the general law of perpendicularity to the surface of a
spheroid, is usually considered as owing to the lateral attraction of
mountain masses drawing it toward them ; but a singular case of a
quite contrary nature has been brought to notice in the immediate
vicinity of Moscow, where the operations of the Russian geologists,
confirmed by the subsequent and more recent . researches of M.

84 ANNUAL OF SCIENTIFIC DISCOVERY.

Schweizer, Director of the Imperial Observatory of that city, have
established the existence of a local deviation to the extraordinary
amount of nineteen seconds, within a very short distance of that me-
tropolis. At Moscow, the plumb-line is found to deviate eight seconds
from the spheroidical perpendicular toward the north. At twenty
Russian versts (thirteen English miles) to the northward of Moscow,
this deviation ceases. It does so, also, at twelve versts (eight miles) to
the south of the city ; but on going farther south, it recommences in a
contrary direction, and at twenty-five versts to the south of Moscow is
converted into a southern deviation of eleven seconds. Proceeding from
Moscow in either an easterly or westerly direction, similar phenomena
are observed. As there is nothing deserving the name of a mountain
in the neighborhood of Moscow, it follows, as a necessary consequence,
from these facts, either, 1st. That there exist beneath Moscow enor-
mous cavities, occupied by air, or perhaps by water. 2d. That strata
of some substance of very weak specific gravity exist beneath that
city. Or, 3d, that there extends over the whole of the country sur-
rounding it a generally loose, unconsolidated mass of geological mate-
rial to a depth hopelessly beyond what human labor can ever expect to
penetrate. The interest of the observation does not terminate with
the particular case of Moscow, but seems to indicate that henceforth
in all instrumental determinations depending on the level or the
plumb line, attention must be given to the lithological character of
the place of observation. Here, again, is a point of contact between
the two antithetical sciences of astronomy and geology.

DEFLECTION OF THE PLUMMET CAUSED BY THE SUN'S AND

MOON'S ATTRACTION.

Mr. Edward Sang, in a paper read to the Royal Society of Edin-
burgh, shows that the attraction of the sun causes a deflection of the
plummet, having its maximum about the 240th part of a second, and
proportional to twice the size of the sun's zenith distance ; the deflec-
tion is at its maximum when the sun is 45 above or below the horizon,
and occurs in the vertical plane passing through the attracting body.
The deflection due to the moon has its maximum about the 60th part
of a second, and follows the same law ; it is toward or from the attract-
ing body according as the zenkh distance is less or more than 90.
Upon the cross-level of a transit instrument, the joint effect is to cause
a semi-diurnal oscillation, small at the quarters and rising to the 24th
part of a second at new and full moon ; while the influence upon me-
ridian observations is sufficient to cause a disagreement between the
greatest inclination of the moon's orbit, as observed at St. Petersburg
and Madras, amounting to the fiftieth of a second.

The general conclusion drawn was, that we cannot determine the
positions of the heavenly bodies true to the one hundredth part of a
second, without having made allowance for this source of disturbance.

MEAN DENSITY OF THE EARTH.

In a memoir on this subject, by M. Faye, read at a recent meeting
of the French Academy, the following valuations, from pendulum ex-
periments, are given : 4.39 by Caiiini and Plana, at Mount Cenis ;
4,71 by Maskelyne, Ilutton, and Playfair, at Schehallien, in Scotland;

NATURAL PHILOSOPHY. 85

5.44 by Reich, 5.43 by Cavendish, and 5.56 by Baily. by means of the
torsion balance; and 6.55 by Airy, at the summit and bottom of a
coal-mine.

ATTRACTION AND ADHESION.

The phenomena of attraction and adhesion, as exhibited in solid
bodies, films, liquid globules, etc., have been investigated by Mr. Rich-
ard Norris, whose paper on the subject appears in the Proceedings of
the Royal Society, from which we extract a few experiments. These
Mr. Korris prefaces by reminding his readers that it has long been ob-
served that solid bodies floating on liquids modify the figure of the
surface of the liquid ; pieces of tinfoil or greased bodies depress the
liquid around them, whilst other bodies elevate it, giving rise to small
mounds of liquid bounded by concave lines ; likes attract likes, and
repel unlikes, etc. He states that the following experiments are
arranged to show that these effects of attraction are not peculiar to
floating bodies, and that the only requirement is that the liquid should
be associated with the bodies in which the movement occurs. 1. Let
two balls of sealing-wax, or other material of greater specific gravity
than water, be suspended by hairs in such a manner that they will both
be partially immersed in water to an equal extent, the points of sus-
pension being at a little distance apart, and the suspending hairs- con-
sequently parallel. When brought within the proper range, they will
attract each other in the same manner as the floating bodies. In
doing so they necessarily describe a small arc of a circle, of which the
suspending hair is the radius, and have, therefore, not simply moved
toward each other in a horizontal line, but have been raised to a
higher level. 2. Suspend movably, by means of a thread passing over
a pulley and a counterbalancing weight, a horizontal cork disc, from
the under surface of which a drop of water is hanging. On a support
beneath, formed by three upright pins, place a small piece of paper or
thin glass, on the surface of which there is also a drop of water. On
depressing the disc until the two drops of water touch each other, the
paper or plate will be instantly drawn up to it ; or, if the plate at the
bottom be heavier than the disc, the latter will be drawn down.
3. When a soap-bubble is allowed to fall on an ifregular surface, such
as a piece of lint or flannel, it maintains its spherical shape ; but if a
smooth surface, such as a sheet of glass, be brought into slight contact
with it, the wall of the bubble will be immediatelv attracted and flat-

tened out upon it. In like manner, when two bubbles come in contact
by their convex surfaces and cohere, the cohering surfaces become flat-
tened, and the bubbles in a group cohere by plane surfaces.

STEAM BOILER EXPLOSIONS.

The following novel ideas respecting the explosion of steam-boilers
were given to the British Association, 1863, by Mr. Airy, the Astrono-
mer Royal. He said, that in considering the cause of the extensive
mischief done by the bursting of a high-pressure boiler, it is evident
that the small quantity of steam contained in the steam-chamber has
very little to do with it. That steam may immediately produce the
rupture ; but as soon as the rupture is made, and some steam escapes,
and the pressure on the water is diminished, a portion of the water is
8

86 ANNUAL OF SCIENTIFIC DISCOVERT.

immediately converted into steam at a slightly lower temperature and
lower pressure, and this, in the same way, is followed by other steam
at still lower temperature and pressure, and so on till the temperature
is -reduced to 212 Fahr. "and the pressure to 0. Then there remains
in the boiler a portion of water at the boiling point, the other portion
having gone off in the shape of steam of continually diminishing pres-
sure. From this it is evident that the destructive energy of the steam,
when a certain pressure is shown by the steam-gauge, is proportional
to the quantity of water in the boiler. By the assistance of Prof. Mil-
ler and George Biddell, Esq., the author has been able to obtain a re-
sult which he believes to be worthy of every confidence. He first
stated, as the immediate result of Mr. Biddell's experiments, that when
there were in the boiler of a small locomotive twenty-two cubic feet of
water, at the pressure of sixty pounds per square inch, and the fire was
raked out, and the steam was allowed gently to escape, with perfect
security against priming, the quantity of water which passed off before
the pressure was reduced to was 2f cubic feet, or one eighth of the
whole. In regard to the use made of Prof. Miller's theory, Prof. Miller
had succeeded in obtaining a numerical expression for the pressure of
steam at twelve different measures of the volume occupied by water
and steam, which expression the author had succeeded in integrating
accurately and had thus obtained an accurate numerical expression
for the destructive energy of steam. In regard to the use of General
Didion's experiments, these experiments gave the velocity of the ball,
in cannon of different sizes, produced by different charges of powder.

Wu 2

The author found, by trial with the formula - -^, ^ , ,

2g x weight ot powder

which of these experiments exhibits the greatest energy per kilogramme
of powder, and had adopted it in the comparison. The result is as fol-
lows : the destructive energy of one cubic foot of water, at sixty
pounds pressure, per square inch, is equal to the destructive energy of
two English pounds of gunpowder in General Didion's cannon experi-
ments. General Didion's experiments were made, as the author under-
stood, with smooth-bored cannon. It cannot be doubted that much
energy is lost in the windage ; some also from the circumstance that
the propelling power*ceases at the muzzle of the gun, before all the
energy is expended ; and some from the coolness of the metal. If we
suppose that, from all causes, one-half of the energy is lost, then we
have this simple result : the gauge-pressure being sixty pounds per
square inch, one cubic foot of water is as destructive as one pound of
gunpowder. In one of Mr. Biddell's experiments, the steam-valve was
opened rather suddenly, and the steam escaped instancy with a report
like that of a very heavy piece of ordnance. This is not to be won-
dered at ; it appears from the comparison above that the effect was the
same as that of firing a cannon whose charge is forty-four pounds of
powder.

ILLUSTRATION OF THE ACTION OF THE SO-CALLED " GIFFARD'S

INJECTOR."

The paradoxical and apparently impossible action of Giffard's in-
jector, employed instead of a feed pump in charging steam-engine
boilers, was illustrated in a remarkable manner by the Abbe Moigno,

NATURAL PHILOSOPHY. 87

at the last meeting of the British Association, by means of a new in-
strument invented by M. Bourdon, of Paris, and called the " Injector
of Solids."

Giffard's injector consists of three tubes united at one point : one of
these brings the supply of water for the boiler from any convenient
source ; the second is for the purpose of conveying the water into the
boiler, and opens below the level of the liquid in that vessel ; the third
brings a jet of steam from the upper part of the boiler. This jet of
steam has the power of injecting a constant supply of water into the
boiler, and so obviating altogether the necessity for a feed pump, and,
apparently impossible as it may appear, not only has the steam power
to inject water into its own boiler, but is capable of feeding another
boiler in which the steam has a much higher pressure than itself.

M. Bourdon's Injector of Solids, which is capable of rendering this
action visible by means of solid bodies, consists of two air vessels, with
a communicating tube capable of being opened or closed at the will of
the experimenter. One of these vessels is made of glass, and furnished
with an aperture closed by a valve opening inwards. The other has a
small air-gun proceeding from it, the barrel of which is directed against
the opening in the first vessel. On condensing air into the two re-
ceivers, it is found that, even when four atmospheres are condensed into
the glass vessel, and only two in that connected with the air-gun, the
bullet driven by the latter has power to open the valve closed by the
pressure of four atmospheres and enter the glass receiver.

ESTIMATION OF DISTANCES AND SPEED.

Many people hear of distances in thousands of yards a usual meas-
ure of artillery distances, and have very little power of reducing
them at once to miles. Now, four miles are ten yards for each mile
above 7,000 yards, whence the following rule : the number of thou-
sands multiplied by four and divided by seven gives miles and sevenths
for quotient and remainder, with only at the rate of ten yards to a mile
in excess. Thus 12,000 yards is 4-f- of a mile, or G-| miles; not 70
yards too great. Again, people measure speed by miles per hour, the
mile and the hour being too long for the judgment of distance and
time. Take half as much again as the number of miles per hour, and
you have the number of feet per second, too great by one in thirty.
Thus 16 miles an hour is 16-}-8, or 24 feet per second, too much by |-A
of a foot. London Athenceum.

POWER OF WAVES.

The Paris Cosmos, in describing the effects of a stormy period in.
January, 1863, on the coast of France, gives instances where "blocks
of stone weighing thirteen tons were hurled to a distance of more than
thirty feet, and blocks of three tons to more than one hundred yards.
The outer harbor of Fecamp was destroyed, and the mass of earth torn
from the north side of Cape la Heve was estimated at more than
300,000 square yards."

MOTIONS OF CAMPHOR UPON WATER.

When small pieces of camphor are dropped on the surface of a glass
of water, several curious phenomena may be observed. They im-

88 AXNUAL OF SCIENTIFIC DISCOVERY.

mediately commence to rotate, and move about with remarkable
energy ; varying sometimes in rapidity, but usually conducting their
gyrations in a strange and erratic manner. In order to obtain the best
effects, some precautions are necessary : thus, the camphor should be
tolerably pure, the piece employed should be cut and separated from
the large lump with a perfectly clean instrument, and contact with the
fingers should be scrupulously avoided. Moreover, the glass should be
quite clean and the water pure. When these conditions are satisfied,
the phenomena are very striking. In the Annual of Sci. Dls. for 1863,
p. 131, the account of some operations by Mr. Tomlinson of Lon-
don on this subject was published. The following additional mem-
oranda of interest have recently been laid before the public by Mr.
Lightfoot, another experimentalist. This latter gentleman states,
that if instead of using a torn or cut fragment from a lump of camphor,
one or two fine crystals are detached with a clean needle-point from the
cork of a phial in which camphor is kept, and these are let fall on
clean water, they at once begin to move about with wonderfully in-
creased rapidity, darting away in various directions, as if shot from
some miniature engine, or endowed with life and a will of their own ;
each crystal quivering and rocking on the water with an apparently
high degree of indignation at its ibrced contact with the humid sur-
face. This fury gradually diminishes, and a regular dance begins ; the
various particles select partners to some of which they wilt seem to
cling with pertinacity ; whilst others will either remain indifferent, or,
if attracted, will only stay a very short time in embrace, and wander
again in search of more congenial floating associates. The explana-
tions which Mr. Lightfoot gives of these movements is the emanation
of a vapor from the volatile camphor, which has a very low tension ;
the water upon which it floats being capable of dissolving and diffus-
ing this vapor more readily in certain directions of the crystalline axes,
thereby removes sufficient vapor pressure at those points for the oppo-
site side to drive about (by recoil) the nicely-suspended particle. In
certain positions two crystals of camphor will attract each other, whilst
in other situations there is a mutual repulsion. It will sometimes hap-
pen that two crystals of camphor may be thrown on the water and not
have any tendency to locomotion. When this is the case, a continual
trembling or vibration will be noticed in the crystal. When two such
stationary vibrating crystals come in contact by attraction, immediate-
ly an eccentric, irregular change of place occurs, as if the force agitat-
ing each previous to the grouping, produced a new resultant force, in
obedience to which the combined crystals move.

As- above stated, it is of essential importance that in separating and
placing the camphor in water everything should be quite clean, and
that the fingers should not touch the camphor in any stage. The
reason of this is found in the circumstance that if camphor is actively
moving on water, and the most minute particle of certain greasy sub-
stances touch the water, instantaneously, as if by some magic, the cam-
phor is deprived of all motion. The scene of previous activity is changed
into immobility. This curious property has been made use of by Mr.
Lightfoot to detect grease in quantities so extremely minute as would
appear almost fabulous, for camphor cannot be made to rotate on water
containing the most infinitesimal portion of grease. Mr. Lightfoot has

NATURAL PHILOSOPHY. 89

*

made use of this test in a most ingenious manner, to distinguish be-
tween the two different methods of dyeing cloth with madder and with
garancine. It is difficult and often impossible for calico-printers and
merchants to distinguish between the two ; and as the garancine dye is
more fugitive than the first, and also of less intrinsic worth, it is some-
times substituted for it. There is however, a slight difference in the
process of manufacture, madder-dyed goods are, in one stage of the
process, passed through a solution of soap to fix the color, whilst in
garancine-dyed goods the soap is replaced by hypochlorite of lime. By
proceeding as follows, it is easy to distinguish between the two kinds
of dye : Let camphor rotate on water in any glass vessel, as previously
described, then immerse a small strip of the cloth to be tested. If the
rotation stops, we infer the presence of soap, and conclude it to have
been dyed with madder. But if, on plunging in the small piece of
cloth, the rotation is not stopped, we then arrive at the conclusion that
garancine was the dyeing material used. In like manner the purity
of water may also, to a certain extent, be tested by dropping a frag-
ment of camphor upon its surface.

CURIOUS ELECTRICAL PHENOMENA.

Prof. Tyndall publishes the following account of some curious
electrical phenomena observed by Mr. R. Watson, and a party of
tourists in ascending a portion of the Jung frau Mountain in Switzer-
land. Mr. W., in a letter to Prof. Tyndall says, On the 10th of July,
1863, I visited with a party of three, and two guides, the Col de la
Jung frau. The early morning was bright, and gave promise of a fine
day, but, as we approached the Col, clouds settled down upon it, and,
on reaching it, we encountered so severe a storm of wind, snow, and
hail, that we were unable to stay more than a few minutes. As we
descended, the snow continued to fall so densely that we lost our way,
and, for some time, we were wandering up the Lotsch Sattel. "We had
hardly discovered our mistake when a loud peal of thunder was heard,
and shortly after, I observed that a strange singing sound, like that of a
kettle, was issuing from my alpenstock. We halted, and, finding that
all the axes and stocks emitted the same sound, stuck them into the
snow. The guide from the hotel now pulled off his cap, shouting that
his head burned; and his hair was seen to have a similar appearance to
that which it would have presented had he been on an insulated stool,
under a powerful electrical machine. We all of us experienced the
sensation of pricking or burning in some part of the body, more
especially in the head and face, my hair also standing on end in an
uncomfortable but very amusing manner. The snow gave out a hiss-
ing, as though a heavy shower of hail were falling ; the veil on the
wide-awake of one of the party stood upright in the air, and on wav-
ing our hands, the singing sound issued loudly from the fingers. When-
ever a peal of thunder was heard, the phenomena ceased, to be re-
sumed before the echoes had died away. At these times, we felt
shocks, more or less violent, in those portions of the body* which were
most affected. By one of these, my right arm was paralyzed so com-
pletely that I could neither use nor. raise it for several minutes, and I
suffered much pain in it at the shoulder-joint for several hours. At
half-past twelve, the clouds began to pass away and the phenomena

8*

90 ANNUAL OF SCIENTIFIC DISCOVEEY.

finally ceased, having lasted twenty-five minutes. We saw no light-
ning, and were puzzled at first as to whether we should be afraid or
amused.

INTERESTING ELECTRIC ILLUMINATION.

Prof. W. B. Rogers communicates to Sittiman's Journal the follow-
ing observations on a powerful electric illumination, exhibited in Bos-
ton, August, 1863, by Mr. Ritchie, the well-known electrician, as a
part of the display attendant on a public rejoicing. The battery in
question, consisting of 250 Bunsen elements, having each an acting
zinc surface of about eighty-five inches, and grouped in five battalions
of fifty each, was arranged in the dome of the State House ; and the
carbon light, and the photometric apparatus prepared for the purpose
were placed in line across the same apartment, commanding a range
of fifty feet. Prof. Rogers says :

In view of the immense power of the light, as observed in the pre-
vious experiment, I substituted for the 20-candle gas burner, used at
that time as the standard of comparison, a unit ten times as great,
formed by the flame of a kerosene lamp placed in the focus of a small
parabolic reflector, and throwing its concentrated light on a photomet-
ric screen of prepared paper fixed in front of it at the distance of five
feet. Before the observation, the lamp and reflector were so adjusted
as to make the light cast on the near side of the screen equivalent by
measure to the action of 200 candles.

This was done by the intervention of a kerosene lamp fitted up with
a bridge of platinum wire for defining and restricting the height of the
square flame. Such a lamp I find of frequent use in ordinary photome-
try, as, when suitably adjusted, it gives t^e light of about eight stand-
ard candles, and thus transfers the measurement in the photometer to
the wider divisions of the scale. Being suspended in a balance of pe-
culiar construction, its rate of consumption enables us to correct for
any slight departure from the assigned illumination. The lamp thus
regulated was placed with its flat flame twelve inches from the screen,
while the lamp in the reflector was distant sixty inches, and the flame
of the latter was adjusted until the effects on the screen were equalized.

A platform supporting the standard lamp and screen at the assigned
distance was arranged to slide on a horizontal graduated bar, extend-
ing directly toward the carbon points so that the screen should receive
the rays from the electric light and from the reflector perpendiculaiiy
on its opposite faces, In making the observations, the platform was
moved to and fro until the illumination on the opposite sides of the
screen was judged to be equal, and then the measured distances of the
two antagonizing lights from the screen gave by easy computation their
relative illuminating power.

By a series of such observations, it was found that the carbon light
had a force varying from 52 to 61 times that of the lamp with reflector,
making it equivalent in illuminating power to the action of from 10,000
to 12,000 standard sperm candles, pouring their light from the same
distance upon the surface of the screen. This, it will l3e remembered, is
the effect of the unaided carbon-light sending its rays equally in all
directions from the luminous centre, and falls vastly short of the illumin-
ating force of the cone of collected rays which was seen stretching,

NATURAL PHILOSOPHY. 91

like the tail of a comet from the surface of the great reflector. Judging
from some recent experiments on the power of such a reflector to aug-
ment the intensity of the light emanating from its focus, there can be
no doubt that, along the axes of the cone, when brought to its narrow-
est limits, the illuminating force of the carbon light as displayed on the
State House could be rivalled only by that of several millions of can-
dles shining unitedly along the same line.

In the above-described observations, a thick screen was necessary, on
account of the great intensity of the lights to be antagonized. I need
hardly say that the different color of the two lights added much to the
difficulty of the measurements. But, by marking in each case the ex-
treme limits on either side, it was practicable to adjust the screen pretty
accurately to equality of illumination.

The only previous experiment, of precisely the same kind, which I
can recall is that of Bunsen, cited in the books, which was made with
a battery of forty-eight elements. In this, the photometric equivalent
of the carbon light was estimated at 572 candles, or nearly twelve
candles to the cell. My observations show a power more than three
times as great, or about forty candles to the cell ; a difference due no
doubt largely to the more intensive battery at my disposal and the
cumulative effect of its arrangement. I suspect, too, that the elements
in Bunsen's observation were of inferior size, but on this point I am
without definite information.

ELECTRICAL SUMMARY.

Electric Express. M. Bonelli, the Italian electrician, suggests a
new application of electricity for the transmission of letters, light parcels,
&c. A series of coils of insulated wire are adjusted along the route,
and through them runs a pair of rails upon which travels the wagon
which carries the despatch-box. This wagon also carries an electric
battery, and the end of the coils are so adjusted that the battery con-
nection is made, by means of the wheels and rails, through the coil which
it is just about to enter. As the wagon is of sheet-iron, it will be at-
tracted to the centre of the coil, and the momentum which it acquires
will carry it far enough to make the connection through the next coil,
when the impulse is renewed.

This contrivance will make a very pretty philosophical toy, or piece
of illustrative apparatus ; but can it be economically applied on a prac-
tical scale ? Cosmos.

Efficacy of Lightning Conductors. M. Quetelet, in commenting on
a remarkable thunder-storm that raged over a considerable part of
Belgium, in February, I860, states that, in his statistics of the buildings
or vessels struck by lightning, " he found that out of a hundred and sixty-
eight cases in which lightning-conductors had been struck, only twenty-
seven, by reason of grave defects in their formation, had failed to
exercise a preservative power."

Influence of Heat on the Voltaic Battery. M. Carlo Roberti, of Ve-
rona, in a note forwarded to the Academy of Sciences at Paris, states
that, while pursuing some experimental researches with Gauss's appa-
ratus, he was struck first with the irregularity and afterwards with the
progressive periodical intensity of the pile he employed. He was soon
led^o attribute this to the variation of the temperature, due to the

92 ANNUAL OF SCIENTIFIC DISCOVERT.

hourly advance of a solar ray which had penetrated his laboratory. He
immediately conceived the idea of applying this fact to the electric tele-
graph and other purposes, and states that he is now engaged in vigor-
ous experiments, with the view of arriving at the exact numbers which
establish the advantages which may be derived from the phenomena.

Magnetism, Electricity, and Vegetation. In his Physique du Globe,
M. Quetelet tells us that on examining attentively the value of the
monthly magnetic variation, it is found to be in direct relation with the
force of vegetation. When the latter sleeps, which happens in the
months of November, December, January, and February, the magnetic,
variation, at Brussels, is almost uniformly 5' 28", or scarcely half during
the period of its full activity, that is to say, from April to September,
when its mean is 10' 15". It reaches its plenitude in April, when the
mean is 11' 14", for Brussels. In another passage, M. Quetelet states,
that the electricity of the air is intimately connected with the action of
vegetation, and that the two phenomena have a nearly parallel march.
It is not pretended that one depends on the other, but that both arise
from the same cause. The quantity of atmospheric electricity at noon
is much greater in winter than in summer, the relation being about 10
to 1. This augmentation of electric force proceeds in a manner almost
parallel with the number of days of frost and fog, and inversely as the
number of days of thunder, of elevation of temperature, of actinic power.

Terrestrial Magnetism and Temperature. At a recent meeting of
the Royal Society, the Astronomer Royal mentioned that the remark-
able change which had taken place in the phenomena of terrestrial
magnetism, as observed at Greenwich since 1845, was such as might be
expected to take place, were the climate of the northern hemisphere
to become more wintry in its character, while that of the southern
hemisphere remained unaltered. It is already on record that Sir John
Herschel considers the climate of the earth to be undergoing a change
due to some cosmical cause. Is there any connection between his con-
clusions and those of the Astronomer Royal ? To those who take in-
terest in the progress of terrestrial magnetism as a science, it will be
gratifying to know that Mr. Airy expresses himself decidedly in favor
of long-continued simultaneous observations in various parts of the
globe. With series of observations extending over many years it be-
comes possible to institute comparisons, to note fluctuations and disturb-
ances, and to discover something of their laws ; while short and broken
series baffle investigation, and harass the inquirer to no useful purpose.
London Athenceum.

Sun-spots and Auroras. The Comptes Rendus contains a letter
from M. R. Wolf to M. Remmont, in which the former says, " I find, in
accordance with M. Fritz, that the frequency of solar spots corresponds
exactly with that of auroras, so that we observe in the latter both the
period of 11-1- years and the great period of 56 years, the existence of
which I have demonstrated for solar spots."

Thunderstorms and the Moon. M. Bernardin calls the attention of
the Belgian Academy to the fact that many thunderstorms have oc-
curred about the period of the new or full moon, and he invites inquiry
for the purpose of ascertaining whether there is any connection between
the movements of our satellite and the electrical condition of the at-
mosphere.

NATURAL PHILOSOPHY. 93

RESEARCHES IN ELECTRO-PHYSIOLOGY.

M. Matteucci has forwarded to the Academy of Sciences, at Paris,
an analysis of his latest electric researches in relation to physiology,
undertaken with the view of explaining one of the most remarkable
yet obscure laws of the science. He began by proving that the passage
of an electric current in a non-metallic body, which is, however, a con-
ductor of electricity on account of the liquid which it has imbibed, ac-
quires the property termed secondary polarity. By virtue of this
property, if it be touched by the homogeneous ends of the galvanometer,
it is found that this body is traversed by an electric current, directed in
a way opposite to the voltaic current which has excited the polarity.
Such is the case with a cotton wick moistened with water, a vegetable
stem, a membrane, and a nerve, independently of its vitality. Among
these different bodies a nerve is remarkable by the rapidity with which
it is polarized in all its points, and by the intensity of its polarity.

Electricity of the Circulation of the Blood. M. Scoutetten has re-
ported to the Academy of Sciences at Paris an account of some experi-
ments made upon horses which were previously made insensible to pain.
He found that the electric positive sign, indicating the direction of the
current, was constantly from the red, or arterial, to the black, or venous,
blood. He concludes his memoir by saying that since it is demonstrated
that the red blood and the black blood, in their contact through the
walls of the vessels, which act as true porous vases, give stated electric
reactions to the galvanometer, we must admit, that as all the parts of
our body are traversed by sanguineous fluids, there must necessarily be
a constant disengagement of electricity in the most relaxed tissues of
our bodies. Thus each organic molecule is incessantly stimulated by the
electric fluid, and thus under the influence of this excitement, all the
functions of the body are performed. The oxygen contained in the red
blood burns up the organic molecules with which it is in contact, and
produces heat, without which life is impossible. Under the influence
of electricity is effected, during digestion, the selection of the nutritive
molecules and their assimilation. The same action takes place in re-
spiration and in all the other functions. These facts perfectly agree
with the electric phenomena of combustion. The carbon takes the
negative electricity and the surrounding air the positive, or rather, the
current is established between the carbon and the oxygen of the air.
Now, the principal action of the red blood, by reason of the oxygen in
it, is the producing a true combustion in our tissues.

Electric Conductivity of Muscle. Ranke, a German physiologist, has
published, among the results of his investigations into the phenomena of
electric currents in the living muscle, the fact that dead muscle is a
much better conductor of electricity than living muscle, because of the
presence of certain products of decomposition which do not appear till
after death. He concludes, further, that the conducting power of living
muscle is three million times weaker than that of mercury, and one
hundred and fifteen million tunes below that of copper.

ELECTPJCITY BY FRICTION AND BY CONTACT DERIVED FROM ONE

SOURCE.

H. Buff (Ann. tier Cliem. u. Pliarm. Vol. 114) says : For electricity
to be evolved bv friction, it is essential that the two surfaces which are

94 ANNUAL OF SCIENTIFIC DISCOVERY.

rubbed against each other, are different in character, and if traces of
electricity do appear on rubbing together substances of similar kind, it
is owing to their being really in some way modified, either at the be-
ginning or while the friction is taking place. Chemical modifications
in this connection exert a much stronger influence than changes de-
pending on mechanical or physical causes.

The discharging force which makes its appearance at the point of
contact between two conductors, and which is known as " electro-motory
power," although first observed in conductors, is not wholly confined
to them. On the contrary, it shows itself with equal constancy, wherever
two bodies, be they conductors or not, but of different kind, come into
contact, and it causes on one of these bodies the discharge of positive,
and on the other that of negative electricity. In the moment of the
separation of these bodies the fluida formed at their points of contact
are set free in the form of electricity. The direction taken by the
discharge is always the same for the same bodies, be they rubbed
against each other or only brought into contact. The fluida, which are
kept separated during actual contact, in the case of conductors and
while they are thus separated, may be carried off in opposite directions ;
on this principle depends the circulation of electricity in the Voltaic
pile. Bad conductors offer resistance to this carrying away of the
fluida ; on the other hand, they favor the accumulation of frictional elec-
tricity. The process of friction itself not only multiplies the points of
contact, but aids their process of separation to penetrate still deeper.
It, however, does not influence the direction of the discharge ; this de-
pends upon the electro-motory force which again corresponds with or
depends upon the difference between 'the bodies so treated.

THE NATURE OF THE FORCES PRODUCING THE GREATER MAG-

. NETIC DISTURBANCES.

The following are the chief points of discourse on the above subject,
delivered before the Royal Institution, London, by Prof. Balfour Stew-
art, of the New Observatory : When a bar of steel is magnetized, it
has acquired a tendency to assume a definite relation to our earth.
Nothing in science is more mysterious than the cause of this. The
earth, like a great magnet, acts upon a magnetized needle with nearly
a directive force. At the present moment, a mariner's compass-needle
points in a direction of about twenty-one and a half degrees west of
true north, termed a declination to that extent, and at the same time
dips downwards, making an angle of about sixty-eight degrees with the
horizon. This declination and dip vary with time and place. But
there are .other changes which the magnet experiences when kept sus-
pended in the same place. 1. The secular change, viz., during a great
many years. 2. The annual variation. 3. The daily variation ; and
4, a change due to the moon. In addition to these are those curious
and unaccountable changes termed magnetic disturbances, or storms.
Atmospheric storms, even the greatest, are only local phenomena ; but
magnetic storms are cosmical, as has been shown by Gauss and Sabine,
and occur almost at the same moment all over the world. Hence
many colonial observatories have been established. Mr. Stewart having
explained the methods of observation, and referred to diagrams giving
results, showed that these magnetic disturbances are connected with

NATURAL PHILOSOPHY. 95

the sun, inasmuch as they obey a daily law, and are moreover
independent of the light of the sun. They have a yet still more
mysterious relation with our luminary. Schwabe, of Dessau, having
for nearly forty years watched and recorded the spots on its disc, saw
that these spots exhibit a maximum and minimum nearly every ten
years ; and General Sabine having discovered that magnetic disturb-
ances have also a ten years' period, fortunately thought of comparing
the two periods, and found that they were precisely the same, having
the same years of maximum and minimum. This brought us into the
presence of some great cosmical bond, other than gravitation. On one
occasion the sun was believed to be caught in the very act of causing a
magnetic disturbance. On Sept. 1st, 1859, Messrs. Carrington and
Hodgson, independently, observed a bright sun spot, and at the very
same moment the magnets at Kew were found to be suddenly disturbed.
It has also been proved that these disturbances are accompanied by
auroras and also by electric earth-currents, in some cases interfering
with the telegraph wires, both having a ten-yearly period. The na-
ture of the bond by which these phenomena are allied is still a pro-
found mystery. Mr. Stewart, however, with diagrams and models,
endeavored to elucidate it by the application of the laws of induced
primary and secondary electric currents, demonstrated by Faraday.
The earth, being considered as the iron core of an electro-magnet, is no
doubt excited by some primary current (probably in the sun), and,
having a conductor in the upper and rarer strata of the atmosphere, and
another conductor round it in the upper and moist crust of the earth,
has also an insulator in the lower and denser strata of the atmosphere.
Mr. Stewart considers that every time a small but rapid change takes
place in" the magnetism of the earth, it gives rise to a secondary or in-
duced current in the two conductors ; and this occasions the electric
earth-currents and auroras, probably due to the inequality of the
earth's surface. With regard to the spots on the sun's disc, Mr. Stew-
art suggests that, if that luminary, by causing magnetic disturbances,
is capable of producing auroras in the earth's atmosphere, it is surely
capable of producing similar phenomena in its own.

CAUSES OF FAILURE IN SUBMARINE TELEGRAPH CABLES.

A recent article in the London Times states several important facts
in -reference to the causes of failure in various submarine telegraph ca-
bles, and in respect also to the precautions now taken to prevent future
similar disasters.

" Every operation in submarine telegraphy even the great Atlan-
tic line has contributed its quota of valuable experience ; for, though
snccessfully laid by Sir Charles Bright and his assistant engineers, in
spite of its imperfect construction, it was destroyed % the injudicious
electrical treatment it received after submersion. This fact is now so
well established that the cause of the failure of the Atlantic cable may
be considered as set at rest forever. The insulation of that line was
not very perfect, as may be imagined from the infancy of the science
at that time, but yet the electrical power used was such as would in-
fallibly break down even the most perfect cables manufactured at the
present day. Of this our readers may judge when it is stated that the
large induction coils first used in signalling between England and

96 ANNUAL OF SCIENTIFIC DISCOVERY.

America were probably equal in electrical power to 2000 battery cells,
while now it is found inexpedient to use more than two or three cells
in working the longest submarine lines in existence. Some of this
great power was no doubt used in the vain hope of forcing signals
through the line at a greater speed than the very slow and uuremuner-
ative rate at which it has alone been found possible to communicate
through an unbroken length of 3000 miles. The result was disastrous,
but the experience, though dearly bought, has proved of great value.
It has taught electricians the value of moderating the power used in
working lines, and above all has pointed out the imperative necessity
of having no single section of a submarine line of more than six hun-
dred miles in length. To lay long submarine cables in a continuous
length without intermediate stations has been found to answer no oth-
er purpose than that of greatly diminishing the speed of working and
multiplying every imaginable risk both of manufacture and submersion.
The Indian Government, acting under the judicious counsel of their
scientific advisers, have wisely determined to divide the Persian Gulf
cable into three sections, though its total length will not exceed 1500
statute miles."

The Red Sea line was destroyed by faults of another character.
Being laid without any allowance for slack, that the cable might con-
form the more readily to the irregularities of the bottom, the suspended
portions became loaded with barnacles and coral, and crumbled from
its own weight.

" To obviate this cause of danger, which in the above-mentioned
lines has probably occasioned a loss of property to the value of over a
million sterling, the Persian Gulf line is cased in twelve No. 7 gauge
harddrawn iron wires, thickly galvanized, so as effectually to prevent
their corrosion. But, in order to secure more effectually the perma-
nent stability of the line, the whole finished cable is thickly coated with
two servings of tarred hemp yarn, overlaid with two coatings of a
patent composition invented by Sir Charles Bright and Mr. Latimer
Clark. The composition consists of mineral pitch or asphalt, Stockholm
tar, and powdered silica, mixed in certain proportions, and laid on in
a melted state. While yet warm, it is passed between circular rollers,
which give it a round, smooth surface. When quite cold this forms a
massive covering of great strength and perfect flexibility, totally im-
pervious to water, and incapable of being destroyed by the minute an-
imalculae which exist in such abundance in warm latitudes, and which,
when the cable is not protected against their attacks, eat every atom
of hemp, as in the case of the cable laid between Toulon and
Algiers."

Another important fact is stated, that wire varies greatly as much
as fifty or sixty per cent. - - in its capacity for conducting electricity.
The cable for the Persian Gulf is so well selected, and so well protect-
ed by gutta percha and compound, that the loss by leakage is scarcely
appreciable by the most delicate instruments. To such minute per-
fection has the system of testing adopted by the engineers been carried,
that the loss of one thousand-millionth part of the current by leakage
would be detected and estimated. The cost of this submarine section
will exceed $1,500,000.

NATURAL PHILOSOPHY.

97

ON THE COMPARATIVE LIGHT OF THE SUN AND STARS.

The following interesting research is communicated to Silliman's
Journal by Mr. Alvan Clark, the discoverer of the companion to Sirius :

" If we place a lens of known focal distance, one foot for instance,
between the eye and a star of the first magnitude, or one of any con-
siderable brightness, with conveniences for guiding its movement in
distance, to any point where it may be needed, and find the star just
visible, or reduced to a sixth magnitude, when the lens, if a convex, is
eleven feet from the eye, it becomes clear that, since the star has un-
dergone a reduction of ten diameters, it would be visible, if removed in
space to ten times its present distance. This, however, is on the sup-
position that no absorbing or extinguishing medium exists in space. If
a concave lens be employed, the measure must be commenced at the
lens itself, but if convex, at the focal point ; or once the focal distance
must be subtracted from the measure, and the number of focal distan-
ces remaining corresponds to the number of reductions under which the
object is viewed.

Castor is visible, when reduced,

Pollux,

Procyon,

Sirius,

The full Moon, .

The Sun, .

10-3 times.

11 "

12 "

20 "
3,000 "
1,200,000 "

I have actually seen the sun under such a reduction ; attended by
circumstances which have led me to believe that it is about the limit
at which the naked human eye could ever perceive this great
luminary.

I have an under-ground, dark chamber, two hundred and thirty feet
in length, one end terminating in the cellar of my work-shop, and the
other communicating with the surface of the ground by a vertical open-
ing, one foot square, and five feet deep. In a movable partition, be-
tween this opening and the end of the chamber, a lens of such focal
distance as I choose can be inserted. A twentieth of an inch focus I
have employed, of the best finish possible ; its flat side cemented to one
face of a prism with Canada balsam. No light whatever can enter the
dark chamber, except through this little lens. A common, plane, silvered
glass mirror, placed above-ground, over the vertical opening, receives the
direct rays from the sun, and sends them down into the prism of total
reflection, by which they are directed through the little lens into the
chamber. An observer, in the cellar, two hundred and thirty feet dis-
tant, sees the sun reduced 55,200 times ; and its light, in amount,
varies but little from that of Sirius. Upon a little car, movable in
either direction, by cords and a pulley, is mounted another lens, with a
focal distance of six inches. The eye of the observer is brought into a
line with the lenses, or so near it, that he sees the light through the six
inch lens ; then, by the cord, he sends the car into the chamber, to the
greatest distance at which he can see the light, like that from a star of
the sixth or seventh magnitude. At noon, March 19th, with a per-
fectly clear sky, I found the sun visible through the six-inch lens, when
it was removed to the distance of twelve feet from the eye. The dis-
tance between the lenses being two hundred and eighteen feet, the re-
duction by the small lens, if viewed from the point occupied by the six-

9

98 ANNUAL OF SCIENTIFIC DISCOVERY.

inch lens, would be 52,320times ; and that again by the six-inch, dis-
tant from the eye twelve feet, or twenty-four times its focal distance, is
reduced twenty-three times; making the total reduction 1,203,360
times.

It becomes now an important matter to ascertain, as nearly as possi-
ble, the proportion of Alight lost by and through the media above de-
scribed the looking-glass, the prism, and two lenses though joining
the little lens with balsam to the prism, it may be regarded as one
piece. I have only investigated by experiments with artificial lights ;
but I find, when the mirror is placed at the angle which the sun re-
quires at the date above given, the difference in the distance at which
a direct light, and the same light reflected, are brought to a minimum
visible, does not exceed one-eighth part of the entire distance, and
could not reach one-seventh, when the prism and lenses were in-
terposed.

Again : the image of the highly-illuminated atmosphere, for some
degrees about the sun, is admitted with the sun's direct light, through
the little lens, to the dark chamber ; and the light, thus augmented, is
observed in contrast with a darkness greater than that of a clear noc-
turnal sky. The entire loss by reflecting and absorbing is manifestly so
small, and the light of the sky in the immediate vicinity of the sun, so
great, that I can readily believe the waste, in effect, is fully made up ;
especially when considering the absolute blackness of the ground upon
which the light in the dark chamber is projected ; and I can find no
reason to doubt that the sun would appear as a star of the sixth magni-
tude, or be only just visible to the unassisted human eye, even setting
aside the idea of an extinguishing medium, if removed 1,200,000 times
his present distance; and at 100,000 times his present distance, he
would only rank as a pretty bright star, of the first magnitude ; though
his parallax would be double that imputed to any star in the whole
heavens. If his intrinsic splendor generally proves to be less than that
of those stars whose distances have been measured, we need not infer
that it is less than the average of existing stars ; for, in case of a diver-
sity among them, bearing any proportion to that among organic bodies,
on the face of the earth, or the planets of our system where the num-
bers are so comparatively small, the visible stars would, of course, ex-
ceed, upon the average, our sun ; for, by the laws of perspective, the
small ones would be lost to our view, at distances from which the
brighter individuals would appear as conspicuous objects. Such would
be the case with telescopic magnitudes, as well as with those visible to
the naked eye. The number of stars visible, by aid of the more pow-
erful telescopes, is far less, in proportion to the power of the instru-
ments, than those visible to the unassisted eye, or with smaller tele-
scopes. This fact has given rise to the doctrine of an extinguishing
medium in space ; which is accepted by the most able astronomers as
the truth, and has been the foundation of much ingenious reasoning.

Plausible or probable, as this appears, I see no difficulty in under-
standing that an exceedingly great diversity in the intrinsic brightness
of the stellar orbs, promiscuously scattered through space, might result
in the same appearances as those on which this doctrine is founded.
For, at the smaller distances, we should see the whole, both great and
small, when using only moderate powers ; but in the regions bounding

NATURAL PHILOSOPHY. 99

the remotest reach of the great telescopes, though the great and the
small might be there, it would be only the great that we should see ;
and those only as the most minute specks of light that can be im-
agined.

The vast number of smaller, or more moderate lights, like our sun,
which may remain concealed among those of extraordinary splendor,
}-et so remote as only just sensibly to impress our vision when aided to
the utmost that human skill can do, will be better understood when we
consider the ratio in which an increase of radius increases the cubic
contents of a sphere. Upon the outer limits of such a sphere as would
embrace the great mass of telescopic stars, a moderate depth, extended
round the whole, would afford an immense amount of room for stars of
all imaginable sizes. I desire to be particularly understood, that it is
in those very remote regions, or beyond where any telescope, now in
use, can possibly show stars of the average, or smaller sizes, that we
may look for the modification introduced, by such supposed diversities,
into the investigation of this doctrine of an absorbing medium. Were
all the stars in existence of one pattern, one uniform brightness, scat-
tered broadcast through all space, I think the great telescopes would
count up more nearly the numbers belonging theoretically to their
powers than they now do. However, with these suggestions, I leave
this interesting branch of my subject for the present.

The ratio, in which the light from a celestial object diminishes with
an increase of distance, needs no explaining; and I will close by
briefly giving, in tabular form, my own results, with those published by
Mr. Bond oi'the Harvard College Observatory, and by Dr. Wollaston,
in the Transactions of the Royal Society of London, of comparisons be-
tween the bright'star a Lyra3 and the sun.

To bring the magnitude of our sun to an equality with that of this
star, his distance would require to be increased, according to

Wollaston, nearly 425,000 times.

Bond, 155,000 "

Clark, 102,000 "

"She light received from these luminaries differs, according to

Wollaston, as 180,000,000,000 to 1

Bond, 24,000,000,000 "

Clark, 10,400,000,000 "

I have alluded to the light in the atmosphere about the sun, as giv-
ing an increase to his photometrical force, though I am aware that
such must be the case with a star ; and it must bear the same propor-
tion to the star's light that it bears to the sun's light. The difference,
in effect is here : we have several thousand stars playing into our at-
mosphere at once, but only one sun. If the distances imputed to
several of the stars, from parallax, can be true, I am sure those having
the taste, talent, and leisure, necessary for following up photometrical
researches with efficiency, cannot fail to find our glorious luminary a
very small star ; and to the human understanding, thus enlightened,
more than ever must the heavens declare the glory" of God.

100 ANNUAL OF SCIENTIFIC DISCOVERY.

THE TENEBROSCOPE FOR PROVING THE INVISIBILITY OF LIGHT.

At the last meeting of the British Association, the Abbe Moigno
exhibited and described an instrument invented by M. Soieil, of
Paris, for illustrating the invisibility of light, and called the " Teuebros-
cope." It is well known to scientific men, although the general public
do not sufficiently appreciate the fact, that light in itself is invisible
unless the eye be so placed as to receive the rays as they approach it,
or unless some object be placed in its course, from whose surface the
light may be reflected to the eye, which will generally thus give notice
of the presence of that object. Thus, if a strong beam of sunlight
be admitted into a darkened chamber through a small opening, and re-
ceived on some blackened surface placed against the opposite wall, the
entire chamber will remain in perfect darkness, and all the objects in
it invisible, except in as far as small motes floating in the air mark the
course of the sunbeam by reflecting portions of its light. Upon pro-
jecting a fluid or small dust across the course of the beam its presence
also becomes perceptible. The instrument exhibited consisted of a
tube with an opening at one end to be looked into, the other end
closed, the inside well blackened, and a wide opening across the tube
to admit strong light to pass only across. On looking in, all is perfect-
ly dark, but a small trigger raises at pleasure a small ivory ball into
the course of the rays, and its presence instantly reveals the existence
of the crossing beam by reflecting a portion of its light.

THE STAR CHROMATOSCOPE. BY M. CLAUDET.
The scintillation and change of colors observed in lookino- at the

t < ^j

stars are so rapid that it is very difficult to judge of the separate
lengths of their duration. If we could increase on the retina the
length of the sensations they produce, we should have the better means
of examining them. This can be done by taking advantage of the
power by which the retina can retain the sensation of light during a
fraction of time which has been found to be one-third of a second a
phenomenon which is exemplified by the curious experiment of a piece
of incandescent charcoal revolving round a centre, and forming a con-
tinual circle of light. It is obvious that if the incandescent charcoal,
during its revolution, was evolving successively various rays, we could
measure the length and duration of every ray by the angle each would
subtend during its course. This is precisely what can be done with
the lio;ht of the star. It can indeed be made to revolve like the incan-

c^

descent charcoal, and form a complete circle on the retina. When we
look at a star with a telescope, we see it on a definite part of the field
of the glass ; but if with one hand we slightly move the telescope, the
image of the star changes its position, and during that motion, on ac-
count of the persistence of sensation on the retina, instead of appear-
ing like a spot, it assumes the shape of a continued line. Now if, in-
stead of moving the telescope in a straight line, we endeavor to move
it in a circular direction, the star appears like a circle, but very irregu-
lar, on account of the unsteadiness of the movement communicated by
the hand. Such is the principle of the instrument employed by the
author to communicate the perfect circular motion which it is impossi-
ble to impart by the hand. The instrument consists of a conical tube,

NATURAL PHILOSOPHY. 101

placed horizontally on a stand, and revolving on its own axis by
means of wheels ; inside this tube, a telescope or an opera-glass is
placed, by which, by means of two opposite screws, the end of the
object-glass can be placed in an eccentric position in various degrees
according to the effect desired, while the eye-glass remains in the
centre of the small end of the tube. Now, if we understand that
when the machine makes the tube to revolve upon its axis, the tele-
scope inside revolves in an eccentric direction, during the revolution
the star seen through it must appear like a circle. This circle exhibits
on its periphery the various rays emitted by the star, all following each
other in spaces corresponding with their duration, showing also blank
spaces between two contiguous rays which must correspond with the
black lines of the spectrum. The instrument, in fact, is a kind of spec-
troscope, by which we can analyze the light of any star, study the
cause of the scintillation, and compare its intensity in various climates
or seasons and at different altitudes. Proc. " British Association"
1863.

SOME PHENOMENA PRODUCED BY THE REFRACTIVE POWER OF

THE EYE.

In a paper read before the British Association, 1863, by Mr. A.
Claudet, the author gave an explanation of several effects of the re-
fraction of light through the eye ; one of which is, that objects
situated a little behind us are seen as if they were on a straight line
from right to left. Another, that the pictures of external objects
which are represented on the retina, are included in an angle much
larger than one-half of the sphere at the centre of which the observer
is placed ; from this point of view a single glance encompasses a vast
and splendid panorama extending to an angle of 200. This is the
result of the common law of refraction. All the rays of light passing
through the cornea to the crystalline lens are more and more refracted
in proportion to the angle at which they strike the spherical surface
of the cornea. Consequently, the only objects which are seen in their
true position are those entering the eye in the direction of the optic
axis. By this refraction, the rays which enter the eye at an angle of
90 are bent at 10, and appear to come from an angle of 80. This
phenomenon produces a very curious illusion. Where we are lighted by
the sun, the moon, or any other light, if we endeavor to place our-
selves in a line with the light and shadow of our body, we are sur-
prised to find that the light and the shadow seem not to be connected
at all, and that, instead of being in a line, they appear bent to an
angle of 160 instead of 180, so that we see both the light and the
shadow a little before us, where they are not expected to be. The
eye refracts the line formed by the ray of light, and the shadow and
the effect is like that of the stick, one-half of which being immersed in
water, appears crooked or bent into an angle at the point of immer-
sion. This enlargement of the field of vision to an angle of 200, is
one of those innumerable and wonderful resources of nature by which
the beauty of the effect is increased. Our attention is called to the
various parts of the panorama which appear in any way a desirable
point of observation, and we are warned of any danger from objects
coming to us in the most oblique direction. These advantages are
9*

102 ANNUAL OF SCIENTIFIC DISCOVERY.

particularly felt in our crowded towns, where we are obb'ged to be
constantly on the lookout for all that is passing around us.

BREWSTERIAN LIGHT FIGURES.

Prof, von Kobell, of the University of Munich, -has recently pub-
lished an account of some interesting experiments similar to those
made by Brewster in 1837, relating to the appearance of bright stars,
elliptical colored rings, and various coruscant forms visible, at certain
angles, in particular minerals and salts. Pliny was aware of this phe-
nomenon, and mentions a stone that he calls Astreos, which showed a
bright star reflected within it. The stone he alludes to is, however, be-
lieved to be no other than a sapphire, which presents the brilliance de-
scribed.

For a long time, it was believed these appearances were only to be
seen in sapphires and garnets, until about the same time as Brewster,
Babinet and Volger discovered the incorrectness of that opinion.

Babinet found that the phenomenon was produced by numberless
parallel grooves or furrows, whose sides were all situated at regular
angles to each other ; so that the light which fell on the crystal was
reflected back from an infinitesimal number of such furrows' sides or
little angular slopes. He therefore gave the forms of light thus pro-
duced the name of "trellis-work appearances;" and the more simple
forms may be produced by engraving on a smooth copperplate the fit-
ting parallel lines in close proximity to each other, and then, in a
darkened room, holding the plate before a candle in such wise that the
reflected light of the flame be transmitted from the plate to the eye.
In this case, a streak of light is perceived on the spot where the lines
are drawn ; should, however, two sets of lines be drawn on the plate at
rirrht angles to (crossing) each other, a streak of light crossing the other
bright streak at right angles will be seen. If the lines on the plate
the rows of little furrows rather cross each other at an acute angle,
then the lines of the bright cross, which becomes visible, are also at an
acute angle to each other. Should the drawn lines all emanate from a
common centre, then, if the light be transmitted at a certain angle, a
parhelion is observed. This last appearance may often be seen in a
small piece of glass rod about one-third of an inch thick, when the base
of the portion thus cut off is ground smooth. Be it observed, however,
that it is not every piece which shows it. By bringing this at a proper
distance between the eye and a taper, as above described, a ring of
light is seen, in the midst of whose periphery the flame of the candle
will be placed. In crystals, a perfectly formed parhelion is very seldom
seen.

Babinet attributed these appearances to the filamentous structure
and the corresponding laminated transits of the crystal. Volger called
attention to the fact, that very often it is the various faces of a twin
formation which cause this coruscation, and that the star-like appear-
ance in a ribbed or striped outer crystalline surface changes when the
said surface is polished and then again looked through. " But," ob-
serves von Kobell, " neither of them makes any mention of the re-
searches which Brewster, contemporaneously with Babinet, made in
the matter, by experimenting with surfaces naturally corroded, as well
as with those whose inner structure was made available for the pur-

NATURAL PHILOSOPHY. 103

pose, either by a slight artificial corrosion or by roughening the surface
of the crystals by means of friction."

Brewster observed, that when he used water, muriatic acid, nitric
acid, etc., as a corrosive, the figures changed according to the corrosive
used. When, however, the surface of the crystal was prepared, by
rubbing on a stone or by means of a file, similar figures were produced,
but not clearly and distinctly formed ; and, what was most extraordi-
nary they appeared in a position directly the reverse of those produced
by corrosion.

Brewster examined minutely crystals of the cubic, pyramidal, and
hexagonal systems only ; with those of the rhombic and the klinic sys-
tems he could obtain no determined results by means of artificial corro-
sion.

It may be well here to give a few hints as to the method to be ob-
served when experimenting with crystals whose surfaces are to be thus
etched. An essential necessity is that such surfaces be smooth and
polished, and that a beginning be made with only a slicjlitly corroding
power. For salts easily soluble in water, Prof, von Kobell adopted
the following mode of procedure. He wetted a piece of woollen cloth
(broadcloth) with water, leaving one part of it dry ; then laying the
crystal evenly on this dry part, he glided it forwards to the part which
was damp and back again immediately. This was repeated according
to circumstances. Xhe crystal should be held by the thumb and fore-
finger of each hand close to the taper, and low down, in order that the
rays may fall upon it as perpendicularly as possible. The eye is to be
brought as close to it as may be, and the crystal then slowly turned
till the appearance of the reflection of the light be clearly seen on its
surface. It will be well to have a sheet of dark paper on the table, at
the spot where you hold the crystal.

If the transparency of the crystal allows the observation of transmit-
ted light, it may then be held between thumb and finger close to the
eye, and the flame of the taper gazed at through it. A side-light is to
be carefully guarded against ; it may be remarked, too, that the bright
figure is generally seen distinctly when you stand two or three or more
steps distant from the candle. In judging of the figure thus seen, you
must not forget to observe whether only one surface has been etched,
or its parallel also ; for the latter will often give the figure of the
former reversed. Thus, for example, if three radiating lines of light
are seen when one surface has undergone corrosion, a star with six
rays would be observed, should the parallel surface have also been
etched.

Such figures are most easily observed in, and produced by, alum.
If a damp piece of cloth be passed once or twice over the smooth sur-
face of an octahedron, and it then be wiped with a dry one, a three-
rayed star at once appears. If wetted thus several times, then a
change takes .place in the central part, and three additional short lines
of light appear in the space between the rays. The star, however,
will be instantlv turned into one with six ravs of li^ht, if the surface of

> ~ /

the crystal be wetted in the manner described above, with a solution
of muriatic or nitric acid. If again wetted with pure water and dried
on a bit of cloth, the six-rayed star instantly changes back into one
with three rays. Brewster also asserts that such an etched or corroded

104 ANNUAL OF SCIENTIFIC DISCOVERY.

surface on which a number of little triangular forms are observed, may
be restored to its original perfect state by dipping the crystal into a so-
lution of alum. To use his own words, " The singular fact in this ex-
periment is the inconceivable rapidity with which the particles in the
solution fly into their proper places upon the disintegrated surface, and
become a permanent portion of the solid crystal."

Von Kobell made the above experiment, without, however, obtaining
the same result as Brewster. But the further he went in his investiga-
tions, the more wonderful and inexplicable were the revelations that
unfolded themselves. The existence of certain infinitesimal combina-
tions became evident, which it is as impossible for the human mind even
to comprehend, as it is for science to follow or to fathom. In one such
crystal is enlocked a world of wonders. Subtle powers are there at
work, elementary changes going on, of which, as yet, we have not the
slightest, the remotest conception ; immutable laws are there governing,
whose existence we have no knowledge of, and whose manifold bear-
ings our bounded understanding would be quite .inadequate to grasp.
And the more we discover on this particular field, the more are we in-
clined to start back in bewilderment at the boundlessness of the horizon
which opens before us.

Well may von Kobell observe, that " theoretic crystallography stands
here, as it were, before a mirror, which shows all the difficulties and
riddles which must be conquered and solved, riddles which, as yet, it
seems, will never be brought to a solution." And he further quotes
what Brewster once expressed when writing on the subject : " In
whatever way crystallographers shall succeed in accounting for the va-
rious secondary forms of crystals, they are then only on the threshold
of their subject. The real constitution of crystals would be still un-
known ; and though the examination of these bodies has been pretty
diligently pursued, we can at this moment form no adequate idea of
the complex and beautiful organization of these apparently simple
structures."

One of the discoveries which Professor von Kobell made gives us
some insight into the marvels of this organization ; not, however, ex-
planatory of it, but showing us, behind newly-discovered wonders,
others half-hidden, receding with systematic order into absolute infinity.

He discovered, namely, that the luminous appearances in calcareous
spar are quite different when the surface of the crystal is disintegrated
by means of nitric acid from those when muriatic acid is employed.
And what is very extraordinary is, that when the corrosion is produced
by muriatic acid, a shining figure is called into existence, regularly
formed of straight lines ; but when nitric acid is used to corrode the
polished face of the crystal, then it is elliptic figures offshoots like
tendrils which show themselves. Here then. Ave have, in addition to
the final phenomena, the fact that the molecular construction of the
crystal is affected by one acid only in one direction, and by another in
a direction quite different. How marvellous the combination of the
atoms, admitting now a channel between them, and now closing it her-
metically against the intruding acid ! What a strange secret of affini-
ties and alienation does this disclose of qualities and powers that we
cannot even conceive of? On a hexagonal prism of calcareous spar,
when the surface is subjected to the corrosive influence of muriatic

NATURAL PHILOSOPHY. 105

acid, a luminous figure appears, resembling the hilt of an ancient
sword.

Without going into further detail, what has been here described will
sufficiently show how interesting the results are which have been ob-
tained by the different experiments. Prof, von Kobell has named
these beautiful luminous appearances after their first discoverer, our
illustrious countryman, Brewster. He calls them " Brewster'sche
Licht-figuren," which may most fitly be rendered by " Brewsterian
Light Figures."

THE COMPOSITION OF LIGHT AND THE LAW OF HARMONIOUS

COLORING.

In a work published some time since, on " Chromotography," by Mr.
Field of London, the author has described an experiment by means of
which he considers he has determined the proportion of colored rays
which constitutes white or solar light. The problem, the solution of
which Mr. Field has attempted, is admitted to be one of the most deli-
cate and unmanageable in the domain of physical science, and phi-
losophers who have instituted experiments and speculated on the sub-
ject from Newton, in former days, to Brewster and Herschel, in our
own time have felt and confessed the difficulties which beset the in-
quiry. It is well known that Newton, from his famous experiment
with the prism, concluded that white or solar light is composed of seven
colors of different refrangibility, which he named violet, indigo, blue,
green, yellow, orange, and red. He also measured the size of the
variously-colored portions of the spectrum, in order to ascertain the
amount of colored light in the sunbeam. Should we admit with New-
ton that white light is made up of no fewer than seven parts, still the
difficulty of measuring the colored spaces of the spectrum is great, if,
indeed, the task be not quite a hopeless one. It is hardly possible to
find two persons who see so nearly alike that they can agree as to
where one color ends and the next begins, and thus no two estimates
of the colored spaces are likely to be the same. A notable instance of
variance is afforded in the values assigned to the snaces by Newton
and Fraunhofer. While they are at one in their opinion of the size of
the orange and indigo spaces, the former finds the yellow and violet to
be in the ratio of 40 and 80, whereas the latter assigns them the very
different ratio of 27 and 109. No subsequent observer has ventured
to alter either estimate, and no one who is familiar with the spectrum
will put much faith in any measurement of it, by whomsoever or with
what care soever it may have been made.

Another analysis of light was afterwards made by Dr. Wollaston, a
high authority in optical questions. As he employed a narrow beam
of light, he obtained a spectrum which consisted apparently of only
four colors, namely, red, green, blue, and violet ; and on dividing the
space occupied by the spectrum into 100 equal parts, he found these
colors to occupy respectively 16, 23, 36, and 25 of the divisions. A
single narrow band of yellow, dividing the red from the green space,
was all he could detect, and he hastily concluded that this color was
merely a mixture of red and green, and consequently not a primary
and important element in the composition of light. This statement of
Wollaston's analysis shows how widely the observations of this observer
differed from those of Newton.

106 ANNUAL OF SCIENTIFIC DISCOVERY.

An important step in the analysis of light was made by Sir David
Brewster when he showed that, by looking at the spectrum through
absorbing media of different colors, it is seen to consist neither of
seven colors as Newton believed, nor of four as Wollaston alleged,
but of three spectra red, yellow, and blue, which have equal lengths
but varying intensities, superposed on one another. Beyond this con-
clusion, however, Brewster did not go ; and he certainly does not
hazard an estimate of the quantify of red, yellow, and blue rays present
in solar light. It is true that in accounting for the presence of the
white light which becomes visible at any point of the spectrum when a
sufficient amount of the colored light at that point has been absorbed,
he conjectures that there is a combination of some definite proportion
of red, yellow, and blue rays which forms the white light. He .conjec-
tures, for example, that if we admit the intensity of white light to be
10, this intensity may result from the combination of three rays of red,
five yellow, and two of blue. These numbers are given, be it observed,
merely by way of example ; and the great master of experimental
optics who gives them is too profoundly versed in his science to im-
agine for a moment that he has attained such knowledge of light as
to express in numbers the amount of its constituent elements. The
preceding hypothesis was given upwards of thirty years ago in more
than one article on the New Analysis of Light, and that "the author
has not changed his views in the interim is proved by his employing,
in the last edition of the Encyclopaedia Britannica, precisely the same
words in elucidating the subject.

A consideration of the difterence in the views of Newton, Wollaston,
and Brewster ought to convince every one of the extreme difficulty
to say the very least of it of determining the amount of colored rays
which compose the sunbeam. Mr. Field offers a solution of the
question that professes an accuracy to which no one of the three now
given lays any claim. His analysis so far agrees with that of Brewster
as to give red, yellow, and blue as the constituents of light, but it
differs from it inasmuch as it assigns definite numerical proportions to
these colors. White light, Mr. Field says, is composed of red, yellow
and blue colors, in the proportion of five, three, and eight respectively.
This, it will be seen, differs wholly from the hypothesis of Brewster, in
which is assigned a proportion of three, five, and two to the same rays.

Mr. Field's analysis of light does not appear to have found favor
with scientists, but the practical art of ornamental coloring has very
generally been inclined to adopt it. Thus Mr. Owen Jones, in his
Grammar of Ornament, states his first law of importance, as follows,
" The primary colors of equal intensities will harmonize with or neutral-
ize each other in the proportion of three yellow, five red, and eight blue,"
etc. The same law is also given in the short handbook on Harmony of
Color issued at the Kensington School of Art, apparently with the
sanction of government, and widely circulated among the art-stu-
dents of the Kingdom. London Athenaeum.

CURIOUS SPECULATIONS ON THE NATURE OF LIGHT.

The following curious speculations on the nature of light are put
forth by Mr. B, S. Barnard, in the London Photograph News :
" ' As white as fine linen,' ' as white as snow,' are frequent compari-

NATURAL PHILOSOPHY. 107

sons ; but they are all dull examples as compared to many chemical
precipitates. Precipitated chalk far outshines the natural varieties,
and fine qualities of magnesia carbonate surpass this. Microscopic ex-
amination indicates that this latter consists of particles, clear and
colorless, but very minute. White lead consists of particles equally
minute and also transparent, but of a yellow-brown color by trans-
mitted light ; consequently, when seen in bulk it appears of a less pure
white. But magnesia cannot be used as a pigment because it possesses
no body ; and the difference between the white lead and the magnesia
in this respect depends upon the different refractive powers of the in-
dividual particles which compose the separate powders. They are
both transparent in their individual particles, but the magnesia is more
so. Thy are both bodies possessed of considerable refractive power,
but the lead is more so. When air intervenes between their particles
the reflective power of both so much exceeds that of air, that they are
hi<rhlv reflecting and verv slio-htlv transmitting: ; but the less absorbing

o v o ** O ( * <J f ~* i ~J

power of the magnesia makes it the whitest, the more reflecting of the
two. But when oil intervenes, as would be the case if they were used
for pigments, the refractive power of the magnesia so nearly coincides
with that of the oil, that much transmission and little reflection is the
result, and this constitutes what painters call want of body. But the
lead so greatly exceeds the oil in refracting power that its reflective
property is not much interfered with, and even with its greater absorb-
ing power it reflects much and transmits little light ; and this is what
painters call great body.

" The length of an undulation of violet light is seventeen millionths
of an inch; the red undulation is twenty-six millionths; undulations
longer or shorter than these not being visible. Again, the length of
the light wave varies in the medium. An undulation in air measuring
four will measure only two and a half when it enters glass, and will
again elongate to its former measure on its exit. When an undulation
passes from air into water, or into the humors of the eye, it likewise
becomes shortened. If we say that luminous undulations, which in air
measure twenty-two millionths of an inch, look yellow when they enter
the eye (that being the wave length belonging to what we call yellow
light), we must also remember that they measure one-third less in that
organ in consequence of its refracting power. We then come to the
singular conclusion that the blue sky is yellow, sunshine is red, and the
rosy tints of evening are not luminous at all till they enter the eye. If
the color depends upon the length of the light wave, and the length
of the wave depends upon the refracting power of the medium through
which it is passing, every beam of light changes color ; red it may be
on passing through the region of the stars, yellow or green it may be
when it enters our earth's atmosphere, blue or violet when it enters
water, non-luminous as it passes through glass. But if light, which we
perceive as violet while it exists in the aqueous humor of the eye, was
red originally, what color must that light be which we perceive is red ?
Its undulations in air must be too long to be luminous at all. This in-
troduces us to the solemn thought that all this vast universe is dark !
Light only exists in the eye. It is only a sensation, a perception of
that which in nature exists as a force capable of producing a sensa-
tion."

108 ANNUAL OF SCIENTIFIC DISCOVERY.

NEW METHOD OF PROPAGATING LIGHT.

"A NEW MODE OF PROPAGATING LIGHT" is the title of a note
lately read by M. Babinet it a meeting of the Academy of Sciences at
Paris, in which he treats of the regular luminous waves which result
from a network or streaked surface placed in the path of a luminous
band. From this proceed many spectra of great brilliancy, anterior
and posterior, the origin of which cannot be derived either from prop-
agation in a straight line, or from reflection, refraction, or diffraction.
The very regular wave from the network borrows each of its elements
from the waves which successively arrive at the network, and thereby
obtains characters quite exclusive. The compensation in the celebrat-
ed experiment of Arago, which, according to Fresnel, prevents the in-
fluence of the motion of the earth from becoming sensible in the
phenomena of the prism, has no place in regard to the network ; and
M. Babinet concludes that, by substituting the network for the prism,
we shall be able to render sensible that influence, so long and so un-
successfully sought for by Fresnel and himself.

COLOR OF WATER.

The color of water has been frequently discussed by physicists.
Arago said, " The reflected color of water is blue, and the trans-
mitted color is green ; " and explained " the green color of the waves
by considering them as prisms of water, of which one of the faces re-
flects white light, which is refracted by the following wave, and thus
goes forth green." Bunsen asserts that water chemically pure is not
colorless, but is of a pure blue color. M. Wettstein, after minute
chemical researches, states that the green color is due to the presence
of organic matters. M. Beetz has recently investigated the subject,
and records his interesting observations in the Bibliotheque Universelle
of Geneva, the results of which are opposed to the conclusion of Arago,
and favor the opinion of Wettstein that the color is due to minute
particles of matter suspended in the water, modified by the color of
the sky and surrounding objects.

THE GREAT FOUCAULT TELESCOPE.

M. Leon Foucault has laid before the French Academy an account
of the great telescope constructed upon his principle for the Observa-
tory, at Paris. He observes that his efforts to obtain large instruments
with reflectors of silvered glass could not be deemed completely suc-
cessful until he had reached dimensions exceeding those of the largest
achromatic objectives, and that it was only by way of establishing a
claim to the recognition of his plans that he announced the formation
of mirrors of 10, 20, and 40 centimetres in diameter. Now, he is able
to speak of one nearly 80 centimetres in diameter, having a focal
length of 4| metres, 1 which has been completed in the establishment
of M. Secretan. This mirror, mounted in a Newtonian telescope, has
been at work for some months, at the Observatory, performing to the
entire satisfaction of the director, M. Chacornac.

iThe metre is 39.3779 inches ; the centimetre 0.3937 of an inch.

NATURAL PHILOSOPHY. 109

CURIOUS OPTICAL ILLUSION ARTIFICIAL GHOSTS.

An interesting optical phenomenon, namely, the production of
spectral apparitions, or ghosts, has been recently devised by Professor
Pepper, of the Polytechnic Institution, London, and most successfully
and practically applied in theatrical exhibitions.

The manner in which the illusion is used for effect, in a theatrical
play, may be stated as follows : -

An actor in the character of a murderer is seen asleep on a lounge
in the rear of the stage, which is dimly lighted. Presently he rises in
his sleep and begins to rave under the tortures of remorse for his crime.
Instantly there appears at his side a bright image of a skeleton, so
luminous that it sheds some light upon the obscurity around. Though
startlingly distinct, it is seen to be only the image of a skeleton, as ob-
jects on the stage are visible directly through the bones. The mur-
derer strikes his sword through the grizzly horror, but it is as impalpa-
ble as air. After a brief space the apparition vanishes as suddenly as
it came. It makes no movement up or down or to either hand, but
simply disappears, the whole effect being so perfect, that the spectator
can hardly bring himself to realize that he is really the subject of a
deception.

The scientific explanation of the phenomena may be thus stated :

When any one looks into a glass or metallic mirror, he sees an image
or ghost of himself. If his neighbor looks over his shoulder he, too, sees
the same ghost. What gives this business of ghost-making its chief
mystery is the plan of concealing adroitly the person or object who or
which is to be ghostified, and showing only the image or ghost, and
thus snapping the otherwise palpable connection between the true ob-
ject, animate or inanimate, and its picture or representation. If a plain
metallic or silvered glass mirror only were employed in producing the
ghost, a child would not be startled at the eifects produced, however
completely the original object might be concealed, from view ; but it is
otherwise, and all are surprised, when an image or ghost is called up
before the observer without any apparent connection with mirror action
at all. .

Now, without going into the questions in optical science respecting
the reflection of light from plane -surfaces, the formation of images by
plane mirrors, or of multiple images formed by glass mirrors, we may
remark that metallic mirrors have but one reflecting surface, giving
only one image of an. object. With glass mirrors this is different.
They give rise to several images which are readily observed when the
image of a candle is looked at obliquely in a common looking-glass.
A very feeble image of a candle is seen, and then a very distinct one.
Behind this there are several others, whose intensity or clearness gradu-
ally decreases until it disappears. This phenomenon or appearance
arises from the looking-glass having two reflecting surfaces, that of
the face of the plate, and that of the layer of metal which covers the
hinder surface of the glass. The greater feebleness of the image re-
flected from the glass than from the metal surface arises from the cir-
cumstance that metal reflects better than glass. It completely intercepts
the light reflected from the original object, and throws it back to the
eye.

10

110 ANNUAL OF SCIENTIFIC DISCOVERY.

In ghost-making, a plate of clear glass is placed between the observers
and where the ghost is made to appear ; and what is seen as the ghost is
nothing more than the feeble image of a true object, produced by re-
flection from the surface of the plate. But the ghost, when well shown,
is an intensely vivid image, the very reverse of feeble ; and the question
is, How is the intensification of an originally feeble image effected ? It
is effected by greatly reducing or extinguishing all other lights, and by
concentrating an intense light on the original object, and thus greatly
increasing the reflecting power of the clear glass plate, and by at the
same time forming a dark background behind the plate, which further
assists in throwing out the image or ghost to the eye of the spectator.
All this is quite a common occurrence in the shop-windows along the
streets, and perhaps still better shown in a lighted railway-carriage at
night. The ghosts of the passengers in the carriage are shown through
the carriage windows upon the apparent ground of the dark sky, and
the carriage lamp, from its being the most luminous object, presents the
most vivid ghost of all.

As applied to theatrical performances the arrangements for the repre-
sentation of a ghost are substantially as follows : Upon the stage of
the theatre is placed a large plate of glass, inclined at an angle toward
the person or object that is to be "ghostified." The audience does not
always perceive this, because the stage is darkened, and because objects
behind the glass may be seen through it. In front of this glass is a
large trap, opening beneath the stage, and forming a square enclosure ;
this is lined with black cloth. The person whose ghost is to be repre-
sented stands in a sloping position against the back of this place, and a
strong light is thrown upon his figure from a j lamp placed opposite.
Now the image of the object is reflected from the glass plate to tho
audience, and this image is seen by them to be as far behind the plate
as the true object is placed in advance of it. The light used to illumi-
nate the person should be very powerful, as the " lime," or Drummond
light, though a good argand burner with a reflector will answer. The
ghost is seen to be illuminated from below up, and this conies of placing
the lamp low and throwing the light on the true object upwards. A
white, lustrous dress given to a female personating the ghost exalts the
effect.

All the room-lights are in the mean time reduced, otherwise the audi-
ence also, as in the case of the passengers in the railway-carriage, would
be converted into ghosts. As much light, and no more, is left on the
stage as admits of the actors on it being seen. These performers see
no ghost ; all their movements are calculated as to place and time.
The ghost placed on the stage, so far as the adaptations of this illusion
have yet gone, is fixed ; a hand or part of the body may be moved, but
not the whole, beyond a very small distance.

Ghost-making, according to the above device of Prof. Pepper, can
be applied for social, as well as theatrical entertainment, and the sim-
plicity of the apparatus employed for the production of the many illu-
sions of which this arrangement is capable will doubtless henceforth
furnish a fruitful source of amusement.

The introduction in London of the above-described optical arrange-
ment into theatrical performances, for the production of ghostly images,
gave rise to a lawsuit of an interesting character. The device in question

NATURAL PHILOSOPHY. Ill

proving profitable as an adjunct to the theatre, a patent was applied
for by Prof. Pepper ; the issue of which was strenuously opposed by
competing exhibitors ; to compass their ends, the latter lodged objec-
tions against the issuing of the patent, just before it was to receive the
Great Seal, and the provisional patentee was allowed one month to
answer the objections. The trial of " the ghost" came off before the
Lord Chancellor, and distinguished counsel appeared for both parties.
Mr. Bower, for the objectors, against Prof. Pepper, put in several affi-
davits to the effect that " the ghost " was somewhat of an antiquated
personage, that he was well known to several public characters, and
could not be justly claimed as the exclusive property of Prof. Pepper.
It was averred that a respectable spectre was shown in London in 1845,
by Herr Dohler, the celebrated conjurer, and that it made the tour of
the whole country with him. Other evidence of a similar nature was
also produced ; and in the course of the arguments on the subject, the
Lord Chancellor himself stated that he had seen a ghost, fifty-five years
before, exhibited by the celebrated Belzoni. Upon the other side, how-
ever, evidence was put in, from no less scientific personages than Prof.
Wheatstone and Sir David Brewster, to the effect that the invention
was new ; and the Lord Chancellor hearing both sides fully, came to
the conclusion that the ghost in question was a new ghost, and accord-
ingly gave judgment for the defendant, Prof. Pepper.

That Prof. Pepper's plan of producing spectral appearances is, how-
ever, a very old affair, seems to be proved by the following extract
from a work written by John Baptista de Porta, in 1558, upon " Natur-
al Magick" ; and translated into English in 1582.

It says : " How we may see in a chamber things that are not I
thought this an artifice not to be despised ; for we may in any chamber,
if a man look in, see those things which were never there ; and there is
no man so witty that will think he is mistaken : Wherefore to describe
the matter. Let there be a chamber whereinto no other light cometh
unless by the door or window where the spectator looks in ; let the
whole window or part of it be of glass, as we used so to do to keep out
the cold ; but let one part be polished, that there may be a looking-glass
on both sides, whence the spectator must look in ; for the rest do nothing.
Let pictures be set over against this window, marble statues and such
like ; for what is without will seem within, and what is behind the
spectator's back he will think to be in the middle of the house, as far
from the glass inward as they stand from it outwardly, and so clearly
and certainly that he would think he sees nothing but truth. But lest
the skill should be known, let the part be made so where the ornament
is that the spectator may not see it, as above his head, that a pavement
may not come between above his head ; and, if an ingenious man do
this, it is impossible that he should suppose that he is deceived."

PHOTOGRAPHY IN CONNECTION WITH ART.

The following is an abstract of a lecture on the above subject, recent-
ly read before the Cornwall Polytechnic Society, of England, by Col.
"VVortley : The lecturer began by alluding to photographic portrait-
ure, as carried on in the present day ; and asked his hearers to disa-
buse their minds of a common error into which most people fall, namely,
that a photograph, because it is taken as it were by machinery, must

112 ANNUAL OF SCIENTIFIC DISCOVERT.

necessarily be a likeness. He stated that this was not the case, and for
the following reasons : " The photograph portrait lens is not a per-
fect instrument, and of necessity magnifies the objects that are nearest
to it, and makes them out of proportion with those situated in a plane
somewhat further from the instrument. To prove this, you have only
to look over any collection of photographic portraits, and you will at
once see that the hands or feet, or any object prominently brought for-
ward, are larger than they should be, to be in due proportion. This
defect, of course more visible in the case, of a hand, foot, or other large
object, alters the proportion, and indeed the expression, of a sitter's head
and face. If, then, in posing a sitter, you allow the chin to be elevated,
or brought forward, it is of course appreciably magnified ; and the fore-
head and eyes, being thrown back at the same time, are diminished,
and a coarse, foolish expression given to a face that may be full of in-
telligence and refinement of feature. This defect is of course much
greater in a cheap, bad lens than in one by any of the best makers ;
though it is one that can easily be guarded against."

Entering on a wider field, the lecturer then alluded to the true diffi-
culty in photographic portraiture, that of being able to give a pleas-
ing and natural pone to a sitter. " You have," said he, " probably the
pictures of many ladies in your respective albums. Now, how many
of those photographs do the ladies justice ? Do any ? Are not the
majority atrocious libels ? In how many of the positions selected by
the photographer would a portrait-painter have placed his sitter ? It
appears singular that such an utter want of artistic feeling and taste
should be shown in the majority of photographic portraits ; but such is
undeniably the case. It is not the want of color in a photograph that
makes it so unsatisfactory. You must all of you have come across, oc-
casionally, most charming portraits in monochrome, chalk, and crayon
drawings, in sepia, and even with pencil and pen and ink, and occasional-
ly a photograph." The lecturer then inquires why the good photograph
is the exception and not the rule ? " In many cases, the professional
photographer has taken up photography as a profession, and so long as
he makes it pay he is content. He does it by machinery. He has no
knowledge of art, no feeling for the beautiful, and in many cases, as
anyone can see, is entirely ignorant of the optical properties of his len-
ses. And the amateur, he takes to photography because it is so nice to
be able to get pictures of all one's friends ! He gets photographs of
them certainly, but between photographs and pictures there is a wide
chasm, bridged by a narrow plank, across which not many of our ama-
teur portraitists have yet walked, and as few of our professionals."

The following counsel was then given as to portrait photography :
It was recommended to adopt the style of taking the head and should-
ers only, making the head about the size of a shilling, and carefully
vignetting it, using always a plain background, varying the color of the-
latter according to the color of the sitter's hair, dress, etc. Then, di-
recting attention to landscape photography, a branch of the art more
practised by amateurs, but requiring on their part more knowledge of
high art, more feeling for all that is beautiful and glorious in nature,
and more perseverance and hard work before they can attain to emi-
nence, Col. AVortley said : "I maintain that the highest art, the
purest taste, is shown in the most scrupulously faithful transcript from

NATURAL PHILOSOPHY. 113

nature itself; because nothing, and no imaginary form or coloring, can
equal, or, I might indeed say, approach in beauty what we, if we cafe
to look for it, and know how to find it, can find for ourselves in nature.
And it is preeminently this earnest desire to seek for and discover the
beauties of nature, and the knowledge of how and where to find them
that distinguish the artist from the mere painte'r or photographer. . . .
If you aim at art in photography, you must study nature, and you must
give as faithful a transcript of nature as you can. Suppose a painter
were to say, ' Well, I cannot be at the trouble to do skies or clouds to
my landscapes ; people must be content with carefully painted fore-
grounds,' what should we think of that individual ? who would look at
his pictures ? what would the photographer himself say to them ?
Then, what does he imagine artists, and all who have a feeling for and
a love of nature, think of his photographs ? I hold all such productions
to be unfaithful to nature and untrue to art.

" But in addition to the real feeling for the beautiful, some knowledge
is desirable, some study of the works of celebrated painters, in order to
know how to combine the various beauties of nature. To give an illus-
tration of my meaning: A view may be very beautiful from a certain
point, but it might happen that, by moving two or three yards one way
or the other, you may make exactly the same view more available, as
a picture, by including some object for the foreground, such as a mass
of rock, an old gate, the trunk of a tree, or any object that may hap-
pen to be within reach.

" There are many other branches of photography to which I might
call your attention, the copying of pictures, photolithography and its
various processes, and composition photography. But I am anxious to
confine myself to photography in connection with its claims to be con-
sidered as a fine art. Composition photography, more than any other,
shows how difficult it is to attain really artistic results in photography,
and shows most forcibly the weak points of photography in its claims to
the rank of a fine art. Wonderful results may be achieved considering
the means at our disposal, but the insurmountable difficulty of control-
ling the sitter's expression of face, not to mention other minor difficul-
ties, will always prevent that class of photography from rising beyond
a certain level, and will always remind us that photography has much
that is mechanical, and that it is necessary to obtain far greater rapid-
ity than any process at present possesses, before composition photography
can worthily assist in claiming for photography in general the dignity
of a fine art. In conclusion I should strongly recommend an amateur
to adopt a rapid process, so as never to have any difficulty in getting
life into his pictures. A man in the foreground, a cow, a wagon, and
team, give life and reality to a photograph, and are often of the utmost
value, and even necessity to the composition of a picture. In the pres-
ent state of photography, with the minutiae of the processes carefully
laid down by experienced photographers, two or three months' hard
study should make any lover of nature and art an accomplished photog-
rapher ; and if he knows somewhat of chemistry, or studies it a little at
the same time, so much the better. . . I am confident that, by photog-
raphy, pictures are to be obtained far superior to anything else ever
produced in monochrome ; and any one can obtain these by study, al-
ways allowing that they have the feeling and taste for nature and art
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116 ANNUAL OF SCIENTIFIC DISCOVERY.

those recently discovered ; and he got up a petition, signed by a num-
ber of artists, and presented either to or through the Lunar Society,
entreating that the manufacture of these pictures might be stayed, as
it would inevitably ruin the picture trade. A sort of foreman of Boul-
ton's, named Edginton, appears to have superintended the production
of these pictures, if he did not actually discover the process by which
the transfer to paper was done. Several of his letters are extant re-
ferring to the subsequent coloring which some of the pictures under-
went ; none of them, however, afford any clew as to the original method
of their production. But a little later, and after the alarm was taken
by the artists, we find a talk of granting Edginton a government pen-
sion. This fell through because of a curious autograph letter of Mat-
thew Boulton's which has been fortunately found. In this letter, offi-
cially addressed to the Minister, he claims for himself the discovery of
the process on account of which Edginton's annuity had been contem-
plated ; he intimates his knowledge that the grant was only intended
to insure the discontinuance of the process, suggests that he could ar-
range this in a much more certain way, and concludes his letter with
a strong hint that he is open- to be dealt with. Whatever ensued as
the result of this letter, it seems very clear that the production of the
pictures was thenceforward discontinued.

Here the evidence comes to an end, so far as regards these curious
paper pictures, and the silvered plates which the highest authorities re-
fer to about the year 1791. In this same year, Thomas Wedgwood,
son of the famous potter, was certainly at work on photography, as is
shown by his bills and orders for apparatus and chemicals. At the
meeting of the Photographic Society there was exhibited, side by side
with the above-mentioned metal plates, a photograph of a neatly-laid
breakfast-table taken upon paper by Wedgwood, and the information
about it tended to the conclusion that it also was done in the year
1791.

Thus far, we have written the history of this curious discovery in ac-
cordance with the evidence laid before the Photographic Society ; but
still there are many links wanting before it can be taken as proved that
the pictures found at Soho were produced by photography. If it shall
be shown that they were so produced, then it will also be established
that at that time photographic feats were done which we cannot nowa-
days accomplish. For it has been proved by chemical analysis that
these pictures do not contain a trace of silver, and must therefore, if of
photographic origin, have been produced by some process that has
been lost to us. That an art promising such great results should have
been suffered to die out, is in itself curious in these days of diffusion of
knowledge ; but still more remarkable is the double coincidence ex-
isting between the independently produced metal and paper photo-
graphs of Boulton and Wedgwood in 1791, and of Daguerre and Fox
Talbot in 1839.

LUNAR PHOTOGRAPHS.

At a recent meeting of the New York Photographic Society, Octo-
ber, 1863, Dr. Henry Draper gave an account of some extensive ar-
rangements made by him for the photographic delineation of celestial
objects, and of the results he had already attained to in this depart-

NATURAL PHILOSOPHY. 117

ment of science. He stated, that in the autumn of 1858, he " deter-
mined to make the largest reflecting telescope in America. Its con-
struction, together with the various improvements successively added,
has occupied me up to the present time, more than five years. The
instrument, which is nearly sixteen inches in aperture and thirteen feet
in focal length, was intended to be devoted to celestial photography, and
consequently contains many novelties especially fitting it for that pur-
pose. It has now the largest silvered-reflector of any instrument in the
world except that in the Observatory at Paris." " The reflecting tele-
scope," said Dr. Draper, " is greatly superior to the achromatic for
photographic purposes. In my instrument, a movement of the sensi-
tive plate, one-hundredth of an inch on either side of the true focus,
visibly injures the image. In the great achromatic at Cambridge, on
the contrary, the position of the plate may be varied over an inch with-
out any noticeable change. The difference is simply that, while by
reflection the visual and chemical rays both converge to the same fo-
cus, by refraction they do not. A sensitive plate, put where the eye
sees the image sharply, produces a fine result in a reflecting telescope,
but does not in an achromatic. Besides this, more light is reflected by
a large silver mirror than an achromatic of equal size can transmit.

" At first, I used speculum metal for my mirrors, but abandoned it at
Sir John Herschell's suggestion in favor of silvered glass, the reflect-
ing power of the latter being ninety-three per cent., while that of the
former is at the best but seventy-five per cent. A large achromatic
only transmits about seventy-five per cent. The glass mirror, too,
weighs not more than one-eighth as much as the metal one, the one
weighing sixteen pounds, the other one hundred and twenty-eight
pounds. It is also greatly more permanent ; for if the silver coating
which covers the glass concave should by chance be injured, it can be
dissolved oft" easily with nitric acid, and the mirror re-silvered in an af-
ternoon ; and this may be repeated indefinitely. A person making such
a silvered glass reflector is content to take the greatest pains to produce
a glass concave of the utmost perfection, for when once it is obtained it
need never be lost. The thin sheet of silver deposited upon it, only
one two-hundred thousandth of an inch thick, copies with the last de-
gree of accuracy the glass beneath, and does not modify the figure of
the surface, but only increases the reflecting power from two or three
per cent, up to more than ninety. This silver coating is transparent,
and shows bright objects, such as the sun, of a light blue tint by trans-
mitted light.

" As regards the degree of excellence that can be reached by such
telescopes, I can only say that mine can show every object that other
instruments of similar size do, and more too. I can see the 18th mag-
nitude pair near (3 Capricorni, discovered by Herschell's eighteen and
a half inch speculum ; and in tests for sharpness of definition, it will sep-
arate the blue component of Andromeda with a power of four hun-
dred, and the instrument, on a favorable night, will bear three times
that power. It must not be supposed, however, that so excellent a re-
sult was obtained without labor. I have ground and polished more
than a hundred mirrors, of sizes varying from nineteen inches to one-
quarter of an inch in diameter.

" The mirror is sustained in a walnut tube hooped with brass and

118 A2TNUAL OP SCIENTIFIC DISCOVERY.

supported in a frame which holds the tube at both ends. This is to
avoid the tremulous motions so common in large instruments. The eye-
piece, or, what is the same thing, the place of the photographic plate,
is stationary at all altitudes, and an observer has never to strain him-
self by awkward positions, but always looks straight forward. When
photographs of the moon are taken, the telescope is not driven by clock-
work, but is allowed to come to rest completely. The sensitive-plate
alone is moved in a direction and at a rate to correspond with the
moon's motion. The difference is, that instead of having to carry more
than half a ton, the clock has only one ounce to move. Of course,
there is no comparison between the precision of movement possible in
the two cases.

" The observatory where the above-described instrument is erected,
is at Hastings, Westchester County, N. Y., and is a building twenty
feet square and twenty-two feet high, and is one-half excavated out of
the solid rock, so as to keep the reflector at a uniform low temperature,
and at the same time give steadiness and immobility to the telescope.
It stands on a hill two hundred and fifty feet above the level of the
sea. The photographic laboratory is attached to the observatory on
the western side, only a few feet intervening between the telescope
and developing sink. It contains all the requisite conveniences for
taking photographs up to three feet in diameter, and is furnished with
a tank which holds a ton of rain-water. This supply is procured from
the roof of the buildings, which are on this account painted with a
stone paint so as not to contaminate the water.

" This instrument," said Dr. Draper, " has been in working order
for eighteen months, but a large part of the time has been unused be-
cause of my absence with the Twelfth Regiment in Virginia, and on ac-
count of professional duties. I have, however, taken some fine photo-
graphs during the past summer. Some changes have been made in
the photographic processes commonly used, in order to fit the pictures
for bearing high magnifying powers. I have negatives which can be
enlarged by a power of thirty-two without showing granulation or other
defects to an offensive degree. The photograph which I show you to-
night is nearly two feet in diameter, and is magnified to two hundred
and ten times the size of the moon, as seen by the naked eye. I have
now another, however, still larger in my observatory, nearly three
feet in diameter, made under a power of three hundred and twenty.
It represents the moon on a scale of seventy miles to the inch. In the
picture before you, attention should be directed particularly to the Ap-
ennine Range, Copernicus, with his reflecting streams, the great groove
from Tycho, the numerous craters, with an internal cone, the irregu-
larities visible in the bottom of the Mare Imbriuna. But it is useless
to particularize; there is an almost inexhaustible supply of objects for
study and admiration.

" The Society will see that, although celestial photography may be, as
yet, only in its infancy, it is rapidly advancing. Every day is giving
origin to improvements, and even now the limit of size in these pictures
is rather owing to the great expense and difficulty of working such
enormous plates than to any intrinsic defect of the images to be copied."

Upon the conclusion of his paper, Dr. Draper exhibited a photo-
graphic view of the moon's surface, the singular distinctness and beauty

NATURAL PHILOSOPHY. 119

of which took the audience quite by surprise. It was a view of the
moon when about half full, and presented a semicircle of nearly two
feet in diameter. The whole of this surface was pictured with great
vividness, covered with long ranges of mountains, or dotted with huge
volcanic summits into the depths^of which one could look down. From
one of these central points, the lava streams could be traced for some
eight inches, which, as an inch in length in the picture corresponds to
a hundred miles upon the moon's surface, afforded ocular evidence of
volcanic agency through a line of eight hundred miles. From another,
vast fissures were seen to radiate, which displayed evidence of convul-
sions reaching through an area of half that diameter. When it is con-
sidered that the largest photographs hitherto obtained of the moon are
not more than from four to six inches in diameter, it will be perceived
how great a triumph has been achieved by the science and skill which
have been requisite for so great an improvement as a picture of twenty-
two inches across.

Foreign Lunar Photographs. Mr. Do la Rue, of London, who has
long been successfully experimenting in lunar photographs, has also
recently succeeded in obtaining two of these images of our satellite, 39
inches (3i feet) in diameter, which he has exhibited to the French
Academy.

THE DIOPTRIC AND ACTINIC QUALITIES OF THE ATMOSPHERE

AT HIGH ELEVATIONS.

In a paper on the above subject, read before the British Association,
1863, by Professor Piazzi Smyth, he stated, that the chief object of the
astronomical experiment on the Peak of Teneriffe in 1856 was to as-
certain the degree of improvement of telescopic vision, when both tele-
scope and observer were raised some two miles vertically in the air.
Distinct accounts have, therefore, already been rendered as to the ma-
jority of clouds being found far below the observer at that height, and
to the air there being dry, and in so steady a state and homogeneous
a condition, that stars, when viewed in a powerful telescope with a high
magnifying power, almost always presented clear and well-defined mi-
nute discs, surrounded with regularly-formed rings, a state of things
which is the very rare exception at our observatories near the sea-level.
Quite recently, however, the author had been engaged in magnifying
some of the photographs which he took in Teneriffe in 1856, at various
elevations, and he finds in them an effect depending on height, which
adds a remarkably independent confirmation to his conclusions from
direct telescopic observations. The nature of the proof is on this wise :
at or near the sea-level a photograph could never be made to show the
detail on the side of a distant hill, no matter how marked the detail
might really be by rocks and cliffs illuminated by strong sunlight ; even
the application of a microscope brought out no other feature than one
broad, faint, and nearly-uniform tint. But on applying the microscope
to photographs of distant hills taken at a high level in the atmosphere,
an abundance of minute detail appeared, and each little separate " re-
tama " bush could be distinguished on a hill-side four and a half miles
from the camera. Specimens of these photographs thus magnified
have been introduced in to the newly-published volume of the Edinburgh
Astronomical Observations.

120 ANNUAL OF SCIENTIFIC DISCOVERT.

HELIOCHRO3IY.

It is well known that M. Niepce Saint- Victor of Paris, has for a long
time occupied himself with the very interesting subject of the repro-
duction of colors by photography. Some time since he announced to
the scientific world his success in obtaining red, blue, and green ; but,
at the same time, he confessed that to obtain a yellow tint in combina-
tion with others was a matter of extreme difficulty, if not, at that time,
practically impossible to him. Of course, there was nothing at all sur-
prising in this, as every one knows that yellow is most troublesome even
in ordinary photography. Within the past year, however, he has an-
nounced to the French Academy, that he has at last succeeded in re-
producing yellow tints by preparing his silver plates in a bath composed
of hyperchloride of soda instead of potash, and he produced specimens
which are said to hold out great expectation of complete success. He
has not yet, however, succeeded in absolutely fixing the colors ; they
remain perfect so long as the plate is kept in the dark, but soon disap-
pear when exposed to the light. But in this respect, also, M. Niepce
has made important progress; for, by the application of gum benjamin
as a varnish to the plate, he has managed to retain- the colors for three
or four days even when exposed to the full glare of a July sun. The
recent memoir read before the Academy by M. Niepce contains much
interesting matter. Amongst other things, he has discovered that all
compound colors are decomposed by the heliochromic process. The
examples given are highly interesting, for instance, if a natural green,
such as that of the emerald, of arsenite of copper, of oxide of chromium,
sulphate of nickel, or carbonate of copper, be presented, it is repro-
duced on the plate ; but, if the green be a compound formed, for in-
stance, of chrome yellow and Prussian blue, that of a textile fabric dyed
with a mixture of the two latter colors, or that produced on glass in a
similar manner, it produces a blue color in whatever manner it is treated.
Moreover, when transparent blue and yellow glasses are used, so as to
produce a green, it matters not whether the blue be before -or behind
or placed between two glasses of the other color, the effect is invari-
ably the same ; no matter how long they are exposed to the light, the
product is always blue. An orange effect produced by the combination
of red and yellow glasses produces invariably red. A red and blue
glass together produce at first a violet, because the plate itself is red ;
but the result is blue. White paper colored green by means of the
recently-discovered Chinese green, made from the juice of the buck-
thorn, has but a sluggish action upon the heliochromic plate ; but, after
a long exposure to the light, a blue-gray is produced ; and the same ef-
fect is obtained from foliage of a grass-green color in the camera ; but
bluish-green foliage, such as that of the leaves of the dahlia, produces
a tint that is almost positive blue. The eye of a peacock's feather is
well rendered in the camera, the tints appearing to vary between
blue and green. Apart from photographic purposes, the experiments
of M. Niepce Saint- Victor promise to be of considerable assistance in
the analysis of the solar spectrum, for it is evident that his attempts to
fix the colors of nature on a heliochromic plate go far to confirm the
new theory which recognizes the existence of three, but not of the seven
primitive colors; namely, violet, indigo, blue, green, yellow, orange
and red.

NATURAL PHILOSOPHY. 121

NOVELTIES IN PHOTOGRAPHY.

Permanency of Photographs. The Paris correspondent of The
Photographic News (London) states that, at a late meeting of the Paris
Photographic Society, M. Davanne presented two photographic pic-
tures, on paper, which had been submitted to the test of exposure in two
exhibitions (18G1 and 1862), and which showed no signs of fading or
alteration whatever. This, then, may be accepted as a satisfactory
proof that photographs, when carefully prepared, are permanent ; for
the pictures in question were submitted to the severest test to which
photographs are ever likely to be exposed, the conditions being every
variation of light, heat, moisture, etc., and they remain as fresh and pure
as at first. It was also remarked that photographs are more liable to
change when kept in a portfolio than under glass exposed to luminous
action. A sulphurized proof, if kept in a perfectly dry place, remains
for a very long time without exhibiting any signs of alteration, while
in a damp place, change is immediately evident. Thus, a photograph
carefully framed is much better sheltered from humidity than when
kept in a portfolio.

Photographic Engraving. The London Athenceum, under date of
November 14th, 1863, states that it has recently seen a beautiful speci-
men of photoglyphic engraving on steel, in other words, a photo-
graphic picture on steel, --effected solely by the agency of light acting
on certain chemicals. The specimen (it is stated by Mr. Fox Talbot)
is quite untouched. It represents an exquisite scene in Java, - - a ra-
vine and rivulet fringed with banana-trees. Not the least wonderful
circumstance connected with it is, that at least 5,000 copies can be
taken before the plate deteriorates. Such a result, after so many years
of labor, must be, for Mr. Fox Talbot, a genuine triumph.

New Photographic Fixing Agent. To fix photographic pictures, a
solution of the hyposulphite of soda has been the common agent em-
ployed. In this, the picture is treated, and is thus prevented from
changing. The London Photographic News asserts that the days of
this agent in photography are numbered, and that sulphocyanide of
ammonium will take its place as a superior agent, by the use of which
a faded positive picture will be unknown. The original source of the
cyanide of ammonium is the thick, tarry liquid remaining after the
separation of the free ammonia from gas liquor : this has long been
known to contain large quantities of sulphocyanide of ammonium, but
hitherto all attempts to separate it from the impurities which accom-
pany it have failed.

Photo-Lithography. A communication has been recently made to
the French Academy, by M. Morvan, in which he describes a new
method for obtaining photographic impressions upon stone, and which
he can afterward print off. He first applies a coating, in the dark, of a
varnish composed of albumen and bichromate of ammonia. Upon this he
lays the right side of the image to be reproduced, whether it be on glass,
canvas, or paper, provided it be somewhat transparent. This done, he
exposes the whole to the action of light for a space of time, varying be-
tween thirty seconds and three minutes, if in the sun, and between ten
and twenty-live minutes, if in the shade. lie then takes off the original

11

l

*

.-
'

I

124 ANNUAL OF SCIENTIFIC DISCOVERY.

to tlie water, and in a few minutes we saw the delicate transparent film
separated from the paper, and floating in the water. After rhising, we
placed a piece of white enamel glass underneath the floating film, and
by a little careful management lifted it from the water uninjured, and
stretched flat upon the glass, where it dried, smooth, bright, and firm.
We now exposed a couple more, and printed until the image was com-
pletely buried ; after which, before toning, we trimmed the print to the
shape we desired, as we found it was a difficult thing to shape the film
when once detached from the paper. We toned this time in a bath
containing a little carbonate of soda, and we observed in the subse-
quent rinsing that the blisters began to rise ; these increased in the
hypo bath, and in the course of the subsequent washings, the film read-
ily separated and floated away from the paper. A subsequent couple
were toned in the lime-bath, washed, and fixed. These also separated
in the subsequent washing without any trouble ; but a longer time was
necessary, some hours elapsing before the film of albumen was quite
detached. The attenuated film, as delicate as the wing of the smallest
fly, at first sight seems quite unmanageable, curling, twisting, and fold-
ing itself with the slightest disturbance of the water ; and if the object
on which it is to be placed be brought under it, and both lifted out of
the water without proper precaution, it will probably be found to have
run up together into a shapeless mass, apparently beyond remedy. If
it be carefully returned to the water, the probability is that it will
gradually float straight out again, and present itself quite uninjured.
A little care and patience will be required. The variety of ornamen-
tal purposes for such transfers will readily suggest themselves. When
transferred to plain white enamel glass, the pictures acquire not only a
beauty as transparencies, but also as positives, which they did not pos-
sess before. The pure white and fine surface seems to impart a won-
drous charm of delicacy and brilliancy altogether unexpected, which,
for locket and brooch portraits, will possess especial value. It is prob-
able that the film so transferred to ivory will be of value to the minia-
ture painter. As ornaments for vases of opal glass, etc., many very
beautiful effects may be produced. In the art of diaphanie, and as an
adjunct to the now fashion-able art of decalcomanie, it will probably be
found useful ; and in a variety of ways which do not now occur to us.
At present, the only protection is a hard varnish, but it is possible that
by the use of an enamel powder fusing at a low temperature, a vitre-
ous surface might be secured."

A NEW KIND OF MINIATURE POSSESSING APPARENT SOLIDITY
BY MEANS OF A COMBINATION OF PRISMS.

A very ingenious and beautiful application of optical principles to
the mounting of photographic miniatures has been recently made by
Mr. Henry Swan, photographic artist of London. The effect of the
new process is to exhibit the subject of the portraiture with life-like
verisimilitude, and in natural relief, the image being apparently imbed-
ded in the thickness of a small inclosed block of glass or crystal, there-
by defining form and expression with a degree of accuracy unattaina-
ble in a flat portrait. The projection of the nose, the moulding of the
lips, and all the gradations of contour, are as distinct a? if an able
sculptor had exercised his skill ; while the hair and the flesh are of

NATURAL PHILOSOPHY. 125

their proper tint, and the whole thing has a singularly vital and comfort-
able look. Indeed, were it not for the reduction in size, it would be
difficult to avoid the belief that an actual man or woman, in ordinary
dress, and with characteristic expression, was presented to your eye.

This curious and beautiful effect is produced ~by a new application
of the principles of binocular vision employed in the ordi nary ^ stereo-
scope. Two portraits (taken at an angle suitable -for the effect intend-
ed) are produced by the ordinary photographic means. To effect the
combination of these, the block of glass'or quadrangular prism, in the
interior of which the solid image is to appear, is composed of two rect-
angular prisms ground to an "angle of about 39 or 40. These are
placed together so as to form one solid quadrangular prism, divided
lengthwise by a thin film of air. If one of the pictures be now placed
at the back of this combination, and the other picture at the side, on
attempting to look through the combination the two images will be su-
perposed on each other (forming one solid image, apparently imbedded
in the crystal), all the rays which fall on one side of a line perpendicu-
lar to the surface of the prism next the eye suffei*ng total reflection at
the inner oblique surface of that prism, while nearly all those rays
which fall on the other side of this line will be transmitted, unaltered
in direction, through the body of the combination. Thus one of the
eyes only perceives the object at the back at the prisms, while to the
other eye the picture at the side is alone visible, and that lying appar-
ently at the back also, producing the perfect appearance of solidity.
It is evident that, to produce these results, care must be taken, not
only that the pictures are not misplaced so as to produce the pseudo-
scopic effect, but also that the picture which suffers reflection shall be
reverted to compensate for the reversion occasioned in reflection.

All these portraits are viewed as transparencies ; the photographs
being printed from ordinary negatives on small mica plates which are
affixed to the prisms.

THE VELOCITY OF LIGHT AND THE SUN'S DISTANCE.

From an article contributed to the American Journal of Science (Sept.
1863), by Prof. Levering, of Cambridge, we derived the following in-
teresting memoranda respecting the above subjects : Four methods
have been devised for determining the velocity of light, two of which
may be termed astronomical and two experimental. The results ob-
tained from these determinations, although agreeing so essentially as to
prove their comparative accuracy, yet differ slightly among themselves
to an annoying and at present inexplicable extent. The first discov-
ered method for obtaining the velocity of light, was by observations on
the eclipses of Jupiter's Satellites, and the result obtained was 193,-
350 statute miles per second. The second process which astronomy
has supplied is through observations on the aberration of light, and
the result obtained gives 191,513 miles as the velocity of light per sec-
ond. The determination of the velocity of light, by the two methods
of astronomy, differ therefore by 1837 miles ; a small quantity compar-
atively, being only 1 per cent, of the whole velocity. It should be also
stated that the velocity which aberration ascribes to light belongs to it
at the earth's surface ; that is, in the dense atmosphere ; whereas the
velocity discovered from the eclipses is that which extends from the

11*

126 A*NNTJAL OF SCIENTIFIC DISCOVERY.

planetary spaces. This distinction, however, will do little toward
bringin^ the two results into greater accordance, as the theoretical dif-
ference of velocities is less than -g^Vo f tne whole, or ^ ess tnan 7( ^ miles.

Compare with tliese conclusions of astronomy two experimental re-
sults on the same subject. The first attempt to obtain the velocity of
light, by direct experiment and test, was made by the eminent French
physicist, Fizeau, in 1849. The plan adopted by him for resolving
this abstruse problem will be readily understood from the following
description. If a wheel finely cut into teeth on its circumference is
put in rapid rotation,* a ray of light, which escapes between two con-
secutive teeth, will, after being reflected perpendicularly by a mirror,
return to strike the wheel at a different point, and either be intercept-
ed by a tooth or admitted at another interstice. Suppose the velocity
of the wheel just sufficient to bring the adjacent tooth to the position
whence the ray first started, in the time which the light occupies in
going to the mirror and returning. In this time the wheel has moved
over an angle found by dividing 360 by twice the number of teeth
which the wheel contains. Therefore the time taken by light, in go-
ing over a line equal to twice the distance of the mirror, is that portion
a second found by dividing unity by the product of the number of
turns the wheel makes in a second, multiplied by double the number
of teeth on the wheel ; the velocity of the wheel being first made the
smallest which will cause it to intercept the light. Such an experi-
ment was made in 1849, by Fizeau, the wheel being placed in a tower
at Suresne, near Paris, and the mirror upon a hill (Montmartre) at the
distance of 8G33 metres. As the wheel contained 720 teeth, and the
slowest velocity which produced obscuration was 12.6 turns a second,
it appeared that light required ^-gy^ of a second to go 8633 metres
and return. Hence its velocity was 313,274,304 metres, or 194,667
miles a second.

Since then, M. Foucault has successfully achieved the measurement
of the absolute velocity of light by an experiment which admits of be-
ing brought within the compass of a single room. The apparatus em-
ployed by him embodied, substantially the principle of Fizeau's appa-
ratus, but was much more complicated, and so accurately devised that
Foucault states that the mean result of his experiments can be trusted
to the fraction of -g^-g-. This result gives for the velocity of light 185,-
177 statute miles per second ; which is less by 6336 miles than the ve-
locity for light usually admitted into science, namely, the velocity ob-
tained from the aberration of light. This discrepancy between the re-
sults of experiment and that of the astronomical determination, which
comes nearest to it, is three times greater than the variation between the
velocity deduced from aberration and that derived from eclipses. Now,
neither the velocity by Foucault's experiment nor the value of aberra-
tion can be charged with a possible error of three per cent., or of any
error approaching to this large discrepancy ; and the question arises,
how is the new velocity of light obtained by Foucault to be reconciled
with the old value of aberration ? It should be stated that aberration
establishes only the ratio between the velocity of light and the velocity
of the earth; but this ratio being established, the astronomer is enabled
to assign the value of the one with all the accuracy which pertains to
his knowledge of the other. Now if this ratio cannot be tampered with,

NATURAL PHILOSOPHY. 127

and if one term of it (the velocity of light) must be diminished three
per cent, to'suit Foucault's experiment, then we must at the same time
diminish the other term (the velocity of the earth) proportionally ;
and the old ratio will be preserved, and the value of aberration will be
left unchanged. Is it possible, therefore, that there can be an uncer-
tainty to the extent of three per cent, in the velocity of the earth ? If
so, the tables are turned ; and, instead of employing the ratio which
aberration supplies to calculate the velocity of light from the velocity
of the earth, as the best known of the two, we henceforth must calcu-
late the velocity of the earth from the velocity of light. For Foucault
has found the latter by experiment more accurately than astronomy
gives the former. If there is an error of three per cent, in the velocity
of the earth, it is an error in space and not in time. To diminish the
velocity of the earth sufficiently by a change of time would demand an
increase in the length of the year amounting to eleven days nearly.

The only other way of reaching the velocity of the earth is by dimin-
ishing the circumference of the earth's orbit, and this, if diminished,
changes proportionally the mean radius of the orbit ; that is, the sun's
mean distance. The question, therefore, resolves itself into this : Can
the distance of the sun from the earth be considered uncertain to the
extent of three per cent, of the whole distance 1

The answer to this question leads to a discussion of the processes by
which the sun's distance from the earth has been determined, and the
limits of accuracy which belong to the received value. To know the
sun's distance, the astronomer studies the solar parallax, which is the
angle between the directions in which two astronomers, located at op-
posite extremities of the earth's diameter, point their telescopes when
they are looking at the sun at the same moment.

As Kepler's third law establishes a relation between the distances of
the different planets from the sun, and their periods of revolution, if th^
astronomer finds either distance by observation, the others can be com-
puted from this law. As the solar parallax is only about eight seconds,
and an error of one-tenth of a second includes an error of more than a
million of miles in the sun's distance, he takes advantage of the law of
Kepler, and selects a planet which comes occasionally nearer to the
earth than the sun. The choice lies between Venus at inferior con-
junction and Mars at opposition.

What are the results which have been obtained ?

1. Only two transits of Venus have occurred since the time when
the sagacious Dr. Halley invoked the attention of posterity to these
rare, astronomical events, as pregnant with the grandest results to
science, namely those of 1761 and 17G9. The astronomers of the last
century did not neglect the charge which Halley consigned to them.
The transit of 1769 was eminently favorable, offering a chance which
comes only once in a millennium ; and whatever verdict posterity shall
pronounce on the deductions from the observations then made, they
will never, says Encke, reproach astronomers or governments with neg-
ligence or want of appreciation toward this golden opportunity. The
solar parallax which Encke deduced from an elaborate discussion of all
the observations, fifty years after they were made, is S".57116. This
corresponds to a solar distance of 95,360,000 statute miles.

Although transits of Venus will take place in 1874 and 1882, and

128 ANNUAL OF SCIENTIFIC DISCOVERT.

astronomers already begin to talk of preparing for them, Encke declares
that, in comparison with that of 1769, the next two transits will be so
unfavorable that nothing short of perfection in the construction of in-
struments, and in the art of observing, can compensate for the natural
disadvantage ; so that the reduction of the possible error in the sun's
parallax within the limit of one-hundredth of a second is hopeless for at
least two centuries more.

2. The solar parallax may also be derived from the parallax of Mars,
when this planet is in opposition. In 1 740, the French astronomer,
Lacaille, was sent to the Cape of Good Hope, and from the parallactic
angle observed between the direction of Mars as seen from that station
and from the observatory of Paris (deduced from observations of decli-
nation), the horizontal parallax of Mars was computed, and consequent-
ly that of the sun. The solar parallax thus found was 10' .20, with a
possible error not exceeding 0".55. Henderson, by comparing his own
observations of the declination of Mars at its opposition in 1832 with
corresponding observations at Greenwich, Cambridge, and Altona,
computed the solar parallax at 9^.028.

The United States Naval Astronomical expedition to Chili, under
the charge of Lieut, J. M. Gilliss, during the years 1849-1852, had
for its object the advancement of our knowledge of the solar parallax,
partly by observations of Mars at opposition, and partly by observations
of Venus during the retrograde portion of her orbit, and especially at
the stationary points, in conformity with a method suggested by Dr.
Gerling; the whole to be compared with simultaneous observations at
northern observatories. Although the observations at Chili were made
on two hundred and seventeen nights, covering a period of nearly three
years, the cooperation of northern astronomers was so insufficient that
only twenty-eight corresponding observations were made. On this ac-
count, the second conjunction of Venus was useless : the other conjunc-
tion of Venus and the second opposition of Mars were of little value ;
and even the first opposition of Mars led to no significant result. Dr.
B. A. Gould has computed the solar parallax from the first opposition
of Mars, observed at Chili, at 8". 50.

3. The solar parallax can also be computed from the law of univer-
sal gravitation. The principle may be thus stated : the motion of the
moon round the earth is disturbed by the unequal attraction of the sun
on the two bodies. The magnitude of the disturbance will be in some
proportion to the distance of the disturber, when compared with the rel-
ative distance of the two disturbed bodies; and this ratio of distances is
the inverse ratio of the parallaxes of the sun and moon. By selecting
one of the perturbations in the moon's longitude, particularly adapted
to this purpose, Mayer, as early as 1760, computed the solar parallax
at 7". 8. In 1824, Burg calculated this parallax, from better observa-
tions, at 8^.62. Laplace gives it at 8''. 61. Fontenelle had said that
Newton, without getting out of his arm-chair, found the figure of the
earth more accurately than others had done by going to the ends of the
earth. Laplace makes a similar reflection on this new triumph of theory :
" It is wonderful that an astronomer, without going out of his observa-
tory, should be able to determine exactly the size and figure of the
earth, and its distance from the sun and moon, simply by comparing his
observations with analysis, the knowledge of which formerly demanded

NATURAL PHILOSOPHY.

129

long and laborious voyages into both hemispheres." The accordance
of the results obtained by the two methods is gne of the most striking
proofs of universal gravitation. Pontecoulant makes the solar parallax,
by this method, 8^.63. Lubboch, by combining Airy's empirical deter-
mination of the coefficient with the mass of the moon, as he finds it from
the tides (viz., Jy) makes the solar parallax 8". 84. If the mass of -fa
is substituted, the parallax is changed to 8". 81. Finally Hansen, m
his new Tables of the Moon, adopts 8^.8762 as the value of the solar
parallax. Moreover, Leverrier, in his Theory of the apparent motion
of the Sun, deduces a solar parallax of 8". 95 from the phenomena of
precession and nutation.

The conclusions of this review are summed up in the following table ;
in which the values of the solar parallax and of the sun's distance, by
the three methods of astronomy, and by the experiment of Foucault,
are placed in juxtaposition ; also the different velocities of light found
by astronomical observations and by experiment.

Observer
or
Computer,

Method.

Parallax.

Distance.

Encke,

By Venus (1761),

8".53

95141830 miles

Encke,

" (1709),

8 .59

95820610

Lacaille,

By Mars,

10 .20

70927900

Henderson,

<t cc

9 .03

90104110

Gilliss and Gould,

CC V

8 .50

96160UOO

Mayer,

By Moon,

7 .80

104079100

Burg,

tc cc

8 .62

94802440

Laplace,

((

8 .61

94915970

Pontecoulant,

cc

8 .63

94089710

Lubboch,

11 CC

8 .84

92313580

<(

cc cc

8 .81

92052970

Hansen,

cc cc

8 .88

91861000

Leverrier,

cc cc

8 .95

91000350

Foucault,

By Light,

8 .86

92087342

Fizeau,

CC (I

8 .51

95117000

Velocity of Light,

By Eclipses,

193350

(( U

<l Aberration,

191513

(C 11

" Fizeau's experiment,

194067

cc ((

" Foucault's experiment,

185177

The three astronomical methods present solar distances, which, even
if we select the most trustworthy decision of each, differ by three or
four millions of miles ; that is, by three or four per cent, of the whole
quantity. Though the best products of the first and third methods
were at one time within a million of miles of each other, an increase of
lunar observations, and especially improvements in the lunar tables,
have now carried that difference up to four millions of miles. If Fou-
cault's experiment were allowed to give the casting vote, it would de-
cide in favor of the third method ; thus making the reflection of La-
place, already quoted, still more memorable.

In regard to the commonly receive'd distance of the sun, which is
based upon Encke's profound discussion of all the observations made at
the last two transits of Venus, the case stands thus : Encke decides,
from the weights of the observations, discussed in the light of the math-
ematical principle of least squares, that the probable error of the sun's
distance, as given by the transits, does not exceed of the whole

w

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four nuluocw < ^"

cnult'-

132 ANNUAL OF SCIENTIFIC DISCOVERY.

i

been made to ascertain what substance allowed them to pass most freely.
The principal results attained to were as follows :

Of the solids experimented with, rock-crystal, ice, rock-salt, Iceland
spar, and the diamond, in the order named, exhibited the greatest photo-
graphic transparency ; while thin glass, mica, iodide of potassium, and
nitrate of potash, considerably affected the transmission of the photo-
graphic rays. The photographic transparency of different liquids may
be indicated as follows : water, 74 ; alcohol, 63 ; chloroform, 26 ; oil of
turpentine, 8 ; of gases, hydrogen, nitrogen, oxygen, and carbonic acid,
have a photographic transparency indicated by the number 74 ; coal
gas, 37; sulphurous acid, and sulphuretted hydrogen, 14 each. This
remarkable fact was also noticed, namely, that solid bodies, when dis-
solved or melted, maintain exactly the same photographic transparency
as when in the solid state. The same was the case when they were
converted into vapor, which showed that this power was part of the
nature of the substance.

The lecturer then described the phenomenon of fluorescence, and
showed that the chemical rays of the spectrum corresponded with the
rays of fluorescence, by taking a photograph in that part of the spec-
trum which, though otherwise invisible on the screen, lighted up a so-
lution of jesculine. He then showed that all metals give characteristic
photographic spectra, some of them bearing a strong family resemblance
to each other, as in the cases of iron, cobalt, and nickel ; the last metal
giving one of the longest spectra observed, and which extended to 190
of the scale. Arsenic, antimony, and tin showed as great differences
in the invisible as visible part of the spectrum. The most interesting
of the metals to study, in this respect, was magnesium, which opened
a wide field for investigation. There were certain points of resemblance
between the spectrum of magnesium and that of the sun, which led to
the supposition that this metal existed in the solar atmosphere. The
comparison of the spectrum of magnesium with that of the sun led also
to some important considerations as to the temperature of the sun. It
was known that the higher the temperature the more refrangible were
the rays of light emitted by a body. We have no conception of the
temperature of the electric spark. The heat of the strongest wind-fur-
nace was estimated at 4500 F., and that of the oxy-hydrogen jet was
supposed not to exceed 15,000 F. ; yet with neither of these could the
same effects be produced as with the electric spark. The lines of the
photographic spectrum of magnesium were not seen in photographs of
the solar spectrum, and yet there was no doubt that this metal was
present in the solar atmosphere. Kirchoff, had discovered that solids,
when heated, give a continuous spectrum, but that bodies in the form
of gas give rays of definite and limited refrangibility, each substance
emitting light of a definite property. He had also noticed that light
from a luminous mass, by passing through ignited vapor, which, per se,
would give bright lines in the spectrum, became furrowed out in dark
bands, occupying exactly the same position in the spectrum as the
bright lines. Now, ignited magnesium vapor emitted green rays which
were absolutely identical with the group of fixed lines b in the solar
spectrum, and it was, therefore, certain that magnesium was a constitu-
ent of the sun. It was, moreover, probable that the heat of the sun
was inferior to that oi' the electric spark, inasmuch as it was insufficient

NATURAL PHILOSOPHY. 133

to bring out the highly refrangible lines observed in photographs of
the magnesium spectrum.

There were thirteen bodies known on earth, which these researches
lead us to suppose existed in the solar atmosphere. Nor are they lim-
ited merely to the sun. Fraiinhofer, had examined the spectra of sev-
eral stars, and found that, although they presented no similarity to that
of the sun, nor to each other, yet that some general relationship between
them was observable. Mr. Huggins and the lecturer had recently
been investigating this subject, and had obtained very perfect maps of
the visible spectra of several stars. They had also obtained a photo-
graph of the spectrum of Sinus. This star is 130,000,000,000 of miles
distant, and the light, which produced the photograph must have left
it twenty-one years ago.

_ A photograph of the spectrum of Capella, which is three times further
distant than Sirius, had also been obtained, the light to produce which,
the lecturer said, must have left that star when the oldest in the room
was a little boy.

Spectrum Analysis applied to the Stars. In a communication
published in the Intellectual Observer (London), by Mr. W. Higgins
F. R. S. who was associated with Prof. Miller in the foregoing de-
scribed investigations, the author speaks more particularly respecting
the results arrived at in respect to the spectra of the fixed stars. He
says, " A single glance at the spectra afforded by Sirius, .Aldebaran,
and a Orionis, will show that the fixed stars have been created upon
the same general plan as our sun, and yet that to this unity of plan is
added variety of purpose in the different groupings of the elements
composing each. In Aldebaran, a Orionis, Capella, Arcturus and oth-
er stars, the sodium line of the solar spectrum is so clearly defined, that
the proof of the presence of this metal in the stellar atmospheres may
be considered as conclusive. Amongst some fifty stars observed, a very
large number, if not all, have lines coinciding with those proved to re-
sult from the presence of hydrogen. This would show that hydrogen
the element upon this earth, next to oxygen, perhaps, the most wide-
ly present, and equally essential with oxygen to the structure of every-
thing that has life is also verv widelv diffused through the universe.

O *' i/

Magnesium and iron would seem to be present in a large number of
stars."

Mr. Higgins and Prof. Miller considered the direct observation*of
the coincidence of stellar with metallic lines so important that they
intend not to rely upon measures, but to compare the metals directly
with the stars. This has already been done with some metals. Most
of the star spectra appear to be as full of lines as is the solar spectrum.
Other lines have been seen in Sirius, in the orange and in the green.

If these distant suns have thus an analogous constitution with our
sun, may we not suppose that the planets, which, doubtless, they uphold
and energize, are of like material structure ? And if terrestrial ele-
ments, with their properties unchanged, be present, may we not fur-
ther surmise, that life in forms not wholly dissimilar to those on this
planet, and which these elements are so eminently adapted to subserve,
may not be wanting ? The spectrum of solar light reflected from the
planets has also been observed. Numerous lines have been measured
in the spectra of Venus, Jupiter, and the Moon. They have also been
12

134 ANNUAL OF SCIENTIFIC DISCOVERY.

recognized in Saturn and Mars. No addition or change of linos has
been seen to indicate that the liuht ha> undergone any change by re-
flection from them. It is probable that, with the exception of the
moon, we receive the light reflected from clouds or vapor in the at-
mosphere of the planets, and not from the true planetary surface. The
light would not, under these circumstances, pass through so great a
length of planetary atmosphere, and in the same proportion would it
be less liable to have any modification impressed iq>on it.

At a recent meeting of the Astronomical Society, Prof. Airy, in an
account of the observations on stellar spectra made at the Royal Ob-
servatory, stated that the line F of Fraiinhofer indicating iron was
seen in most stars, the sodium line 1) in two stars; and a line near-
Iv, but not quite coinciding with G in many. The star a Orionis ap-
peared most like our sun, but generally the stars seemed not to be so
complex in constitution.

7 '< iit/H 'future of the Sun and Stars. Besides the light of the sun,
which, when spread out, forms the visible spectrum, the sun sheds
upon us a large amount of energy invisible as light. Professor Stoko's
investigations have shown that this invisible energy, when passed
through a prism of quart/, is spread out like light, and contains lines
or spaces where this energy is absent, similar to the dark lines in the
visible speetrum. By the substitution of a collodion plate for the eve,
Professor Miller has investigated the invisible spectra of metallic flames.
These are as distinct and characteristic of each metal as is the light
spectrum of each. Observation has shown that the length of these spec-
tra of invisible energy and their lines are closely connected with the
temperature of the source of heat. Thus, when photographs of the re-
frangible portion of the solar spectrum and that of- the metal magne-
sium were compared, it was observed that that of the magnesium ex-
tended much beyond the solar, and it was especially noticeable, that
there was a strong band in the magnesium spectrum just beyond the
limits ol'th" solar. Yet no metal has been proved to be present in the
sun with more certainty than magnesium. Professor Miller regards
this difference as an indication of the solar temperature. The magne-
sium -peeirurn was obtained by the electric spark. If, in place of this
intensely high temperature, the o\ y-hydrogen flame of only 15,000 F.
be substituted, the magnesium spectrum is shortened, and does not ex-
tend be\ ond that of the sun. From this, Professor Miller infers that
" the temperature of the sun may be approximately estimated to be
not higher than that of the oxy-hydrogen flame. It certainly appears
to be far below that of the electric spark." This seems to be scarcely
in accordance -with the known law of the decrease of radiant heat.
This decreasing, inversely as the square of the distance, gives an in-
tense amount of heat to the solar surface. Waterston, in a communica-
tion to the Royal Astronomical Society, in February, 1860, states that
his experiment.-, founded upon the supposition that the difference
tween the temperature in the sun and the temperature in the shade

is a function of the sun's absolute temperature, give above "ten mil-
lion degrees, probably twelve million, Fahrenheit," to the solar sur-
face.

Is it not possible that vapors may exist in the solar atmosphere
which, as Professor Miller shows to be the case with sulphuretted hy-

NATURAL PHILOSOPHY. 135

dro?en, are but imperfectly diactinic, and so arrest these extreme rays
of energy '.' Xot that sulphuretted hydrogen, or any compound bodv,
can be .-upposed to exist upon the solar surface. The elements th'Te,
iiiii-t .-t uid too much aloof, by the mutual hate of the fierce heat, to
unite themselves in alliances with each other. It may be, however,
that conditions unknown to us alter or modify the terrestrial law of de-
crease of heat.

!i -ecmed, however, an object of great interest to know if similar
photographic spectra could be obtained of the stars. Mr. Higgins and
Dr. Miller have already been successful in photographing the more re-
frangible portion of the spectra of Sirius and Capella.

\r : - Observations on Spectral Ana';i*i..< I;/ Prof. Plucker. The
following new vu>ws respecting spectral analysis were presented to the
liriti-h A ociation by Prof. Plueker : " It is generally admitted now,"
he --lid. --that every gaseous body rendered luminous by heat or elec-
tricity sends out a peculiar light, which, if examined by the prism,
gives a well-defined and characteristic spectrum. By such a spectrum,
by any one of its brilliant lines, whose position has been measured,
you may recognize the examined gas. This way of proceeding con-
stitutes what i.s called spectral analy.-is, to which we owe, until this
day, the discovery of three new elementary bodies. In order to give
to spectral analysis a true and certain basis, you want the spectrum of
each elementary substance. Most recently, some eminent philosoph<
in examining such spectra, met with unexpected diiliculties, and doubts
arose in their minds again-t the new doctrine. These doubts are un-
f junded. The fact is, that the molecular constitution of gases is mueh
more complicated than it has been generally admitted to be till now.
The spectra, therefore, always indicating the molecular constitution of
gases, ought to be more complicated also, than it was thought at first.
Uy th< :isiderations, a new importance, a rather physical one, is

given to spectral anal} You may recognize by the spectrum of a

-. not only the chemical nature of the gas, but you may also obtain
indications of its more intimate molecular structure (|iu'te a new
branch of science. Allow me now to select out of the results already
obtained two instances only. Let me try to give what I may call the
history of the spectra of two elementary bodies of sulphur and nitro-
gen. In order to analyze by the prism the beautiful light produced
by the electric current, if it pass through a rarefied gas, I gave to the
tube in which the gas is included such a form that its middle part was
capillary. Thus I got within this part of the tube a brilliant film of
light, extremely fitted to be examined by the prism. After having
provided myself with apparatus more suited to my purposes, I a-ked,
about a year a2o, my friend, Prof. Ilittorf, of Munster, to join me in
taking up my former researches. The very first results we obtained
in operating on gases of a greater density opened to us an immense
field of new inve.-tigation. \Ve found that the very same elementary
substance may have two, even three, absolutely different spectra,
which only depend on temperature. In our experiments we made use
of Ruhmkorifs induction coil, whose discharge was sent through our
spectral tubes. In order to increase at other times the Heating power
of the discharge, we rnudc u_-e of a Leydenjar. Kow, let us suppose a
bpecaral tube, most highly exhausted by Geissler's mercury pump, con-

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138 ANNUAL OF SCIENTIFIC DISCOVERY.

was placed under the jet at various points ; the cloud was cut sharply
off at that point, and when the flame was placed near the efflux orifice,
the cloud entirely disappeared. The heat of the lamp completely pre-
vented precipitation.

This same vapor was condensed and congealed on the surface of a
vessel containing a freezing mixture, from which it was scraped in
quantities sufficient to form a small snow-ball. The beam of the elec-
tric lamp, moreover, was sent through a large receiver placed on an air-
pump. A single stroke of the pump caused the precipitation of the
aqueous vapor within, which became beautifully illuminated by the
beam ; while, upon a screen behind, a richly-colored halo, due to dif-
fraction by the little cloud within the receiver, flashed forth.

The waves of heat speed from our earth, through our atmosphere,
toward space. These waves dasl^n their passage against the atoms
of oxygen and nitrogen, and against the molecutes of aqueous vapor.
Thinlv scattered as these latter are, we mig^ht naturally think meanlv

V V t/

of them as barriers to the waves of heat. We might imagine that the
wide spaces between the vapor molecules would be an open door for
the passage of the undulations ; and that if those waves were at all in-
tercepted, it would be by the substances which form 99^ per cent, of
the whole atmosphere. Three or four years ago, however, it was
found by the speaker that this small modicum of aqueous vapor inter-
cepted fifteen times the quantity of heat stopped by the whole of the
air in which it was diffused. It was afterwards found that the dry air
then experimented with was not perfectly pure, and that the purer the
air became, the more it approached the character of a vacuum, and the
greater, by comparison, became the action of the aqueous vapor. 1 The
vapor was found to act with thirty, forty, fifty, sixty, seventy times the
energy of the air in which it was diffused ; and no doubt was enter-
tained that the aqueous vapor of the air which filled the Royal Institu-
tion Theatre, dining the delivery of the discourse, absorbed ninety or
one hundred times the quantity of radiant heat which was absorbed by
the main body of the air of the room.

Looking at the single atoms, for every two hundred of oxygen and

1 Melloni of Italy, who has been styled the " Newton of Heat," was the first to
apply the thermo electric pile to the investigation of dark, thermal radiations which
are emitted from all bodies below a red heat, by the use of plates, lenses, and
prisms of rock-salt (common salt in blocks), which is transparent to dark heat,
JVJelloni first engaged in these researches, and in fact founded this branch of science.
Prof. Tyndall, taking up the subject where Melloai left it, investigated the rela-
tions of radiant heat to gases and vapors in the following manner : He prepared a
long glass tube closed air-tight at its ends with plates of rook-salt, and which he
could empty and fill with various gases at pleasure. At one end he placed his
source of heat, a canister of hot water, and at. the other the sensitive face of a
thermo-electric pile. By exhausting the air and forming a vacuum, and then intro-
ducing various gaseous bodies, he determined how much dark heat passed through
and also the different absorbing or intercepting powers of the various substances
in the tube. It was found that the simple gases, oxygen, hydrogen, and nitrogen
arrested hardly a trace of the passing heat, acting toward it a.s practical vacuum.
On the contrary, other equally transparent gases, as ammonia, carburetted hydro-
gen, etc., stopped enormous numbers of the dark rays ; in fact, were almost opaque
to them. The small trace of ammonia, exhaled into an apartment by opening a
lady's smelling-bottle arrested many times more of the dark heat rays than the ni-
trogen and oxygen gases which form the body of the atmosphere. Professor
Tyndall found that perfectly pure air stopped an exceedingly minute portion of the
heat, which he assumed as the unit for comparison of other bodies, and upon in-
vestigation it proved that the small amount of aqueous vapor contained in the air
struck down sixty or seventy times as much heat as the gases of the air itself.

NATURAL PHILOSOPHY. 139

nitrogen there is about one of aqueous vapor. This one, then, ig
eighty times more powerful than the two hundred ; and hence, compar-
ing a single atom of oxygen or nitrogen with a single atom of aqueous
vapor, we may infer that the action of the latter is 16,000 times that
of the former. This was a very astonishing result, and it naturally
excited opposition, based on the philosophic reluctance to accept a re-
sult so grave in consequences, before testing it to the uttermost. From
such opposition, a discovery, if it be worth the name, emerges with its
fibre strengthened ; as l^ie human character gathers force from the
healthy antagonisms of active life. It was urged that the result was
on the face of it improbable ; that there were, rqpreover, many ways
of accounting for it, without ascribing so enormous a comparative ac-
tion to aqueous vapor. For example, the cylinder which contained
the air in which these experiments were made was stopped at its ends
by plates of rock-salt, on account of their transparency to radiant heat.
Rock-salt is hygroscopic ; it attracts the moisture of the atmosphere.
Thus, a layer of brine readily forms on the surface of a plate of rock-
salt ; and it is well known that brine is very impervious to the rays of
heat. Illuminating a polished plate of salt, by the electric lamp, and
casting, by means of a lens, a magnified image of the plate upon a
screen, the speaker breathed through a tube for a moment on the salt ;
brilliant colors of thin plates (soap-bubble colors) flashed forth imme-
diately upon the screen, these being caused by the film of moisture
which overspread the salt. Such a film, it was contended, is formed
when undried air is sent into the cylinder ; it was, therefore, the ab-
sorption of a layer of brine which was measured, instead of the ab-
sorption of aqueous vapor.

This objection was met in two ways. First, by showing that the
plates of salt, when subjected to the strictest examination, show no trace
of a film of moisture. Secondly, by abolishing the plates of salt alto-
gether, and obtaining the same results in a cylinder open at both ends.

It was next surmised that the effect was due to the impurity of the
London air ; and the suspended carbon particles were pointed to as the
cause of the opacity to radiant heat. This objection was met by bring-
ing air from Epsom Downs, a field near Newport, in the Isle of Wight,
and a sea-beach. The aqueous vapor of the air from these localities in-
tercepted at least seventy times the amount of radiant heat absorbed
by the air in which the vapor was diffused. Experiments made with
smoky air proved that the suspended smoke of the atmosphere of
London, even when an east wind pours over it the smoke of the city,
exerts only a fraction of the destructive powers exercised by the
transparent and impalpable aqueous vapor diffused in the air.

The cvlinder which contained the air through which the calorific

/ c?

rays passed was polished within, and the rays which struck the interior
surface were reflected from it to the thermo-electric pile which meas-
ured the radiation. The following objection was raised : You permit
moist air to enter your cylinder; a portion of this moisture is con-
densed as a liquid film upon the interior surface of your tube ; its re-
flective power is thereby diminished ; less heat therefore reaches the pile ;
and you incorrectly ascribe to the absorption of aqueous vapor an
effect which is really due to diminished reflection of the interior surface
of your cylinder. But why should the aqueous vapor so condense ?

140 ANNUAL OF SCIENTIFIC DISCOVERY.

The tube within is warmer than the air without, and against its inner
surface the rays of heat are impinging. There can be no tendency to
condensation under such circumstances. Further, let five inches of
undricd air be sent into the tube that is, one-sixth of the amount
which it can contain. These five inches produce their proportionate
absorption. The driest day on the driest portion of the earth's sur-
face would make no approach to the dryness of our cylinder when it
contains only five inches of air. Make it ten, fifteen, twenty, twenty-
five, thirty inches : you obtain an absorption exactly proportional to
the quantity of vapor present. It is next to a physical impossibility
that this could be the case if the effect were due to condensation. But
lest a doubt should linger in the mind, not only were the plates of
rock-salt abolished, but the cylinder itself was dispensed with. Humid
air was displaced by dry, and dry air by humid in the free atmosphere ;
the absorption of the aqueous vapor was here manifest, as in all the
other cases.

No doubt, therefore, can exist of the extraordinary opacity of this
substance to the rays of obscure heat ; and particularly such rays as
are emitted by the earth after it has been warmed by the sun. It is
perfectly certain that more than ten per cent, of the terrestrial radia-
tion from the soil of England is stopped within ten feet of the surface
of the soil. This one fact is sufficient to show the immense influence
which this newly-discovered property of aqueous vapors must exert on
the phenomena of meteorology.

* This aqueous vapor is a blanket more necessary to vegetable life
than clothing is to man. Remove ipr a single summer-night the
aqueous vapor from the air which overspreads this country, and you
would assuredly destroy every plant capable of being destroyed by a
freezing temperature. The warmth of our fields and gardens would
pour itself unrequited into space, and the sun would rise upon a land
held fast in the iron grip of frost. The aqueous vapor constitutes a
local dam, by which the temperature at the earth's surface is deepened ;
the dam, however, finally overflows, and we give to space all that we
receive from the sun. The sun raises the vapors of the equatorial ocean ;
they rise, but for a time a vapor screen spreads above and around
them. But the higher they rise, the more they come into the presence
of pure space, and when, by their levity, they have penetrated the
vapor screen, which lies close to the earth's surface, what must occur?

It has been said that, compared atom for atom, the absorption of an
atom of aqueous vapor is 1G,000 times that of air. Now the power to
absorb and the power to radiate are perfectly reciprocal and propor-
tional. The atom of aqueous vapor will therefore radiate with 16,000
times the energy of an atom of air. Imagine then this powerful
radiant in the presence of space, and with no screen above it to check
its radiation. Into space it pours its heat, chills itself, condenses, and
the tropical torrents are the consequence. The expansion of the air,
no doubt, also refrigerates it : but in accounting for those deluges, the
chilling of the vapor by its own radiation must play a most important
part. The rain quits the ocean as vapor ; it returns to it as water.
How are the vast stores of heat set free by the change from the vapor-
ous to the liquid condition disposed of? Doubtless, in great part they
are wasted by radiation into space. Similar remarks apply to the

NATURAL PHILOSOPHY. 141

cumuli of our latitudes. The -warmed air, charged with vapor, rises in
columns, so as to penetrate the vapor screen which hugs the earth ; in
the presence of space, the head of each pillar wastes its heat by radia-
tion, condenses to a cumulus, which constitutes the visible capital of an
invisible column of saturated air.

Numberless other meteorological phenomena receive their solution,
by reference to the radiant and absorbent properties of aqueous vapor.
It is the absence of this screen, and the consequent copious waste of
heat, that causes mountains to be so much chilled when the sun is with-
drawn. Its absence in Central Asia renders the winter there almost
unendurable ; in Sahara the dryness of the air is sometimes such, that
though during the day " the soil is fire and the wind is flame," the chill
at night is painful to bear. In Australia, also, the therrnornetric range
is enormous, on account of the absence of this qualifying agent. A
clear day, and a dry day, moreover, are very different things. The
atmosphere may possess great visual clearness, while it is charged with
aqueous vapor, and on such occasions great chilling cannot occur by
terrestrial radiation. Sir John Leslie and others have been perplexed
by the varying indications of their instruments on days equally bright
but all these anomalies are completely accounted for by reference to
this newly-discovered property of transparent aqueous vapor. Its
presence would check the earth's loss ; its absence, without sensibly
altering the transparency of the air, would open wide a door for the
escape of the earth's heat into infinitude.

DYNAMICAL THEORY OF HEAT.

Professor Frankland, in a recent lecture before the Royal Institution,
London, presented the following points in reference to the dynamical
theory of heat : The amount of heat necessary to raise the temperature
of a body through a given number of degrees (e. g. from 32deg. to 212
deg.) is termed " the specific heat " of that body, and that an atom of
each solid element requires the same quantity of heat to raise its tem-
perature through the same number of degrees. Hence, at any given
temperature, the amount of heat-force associated with each solid element-
ary atom is the same ; but the proportion of this force evolved during
chemical combination differs in each element (which was shown experi-
mentally in the case of heated balls of lead and iron placed on cakes of
wax ; (he iron dissolving more wax than the lead). It was stated that
the greater the amount of heat evolved during combination, the more
difficult is the compound to decompose ; and it was shown that even
when atoms of the same kind are combined, heat is liberated. This oc-
curs, also, whenever alcohol and water are mixed, when paper is moist-
ened, etc. The heat-force associated with the atoms of matter exists as
molecular motion. When two or more atoms unite or come into col-
lision, a certain amount of this motion is destroyed and takes the form
of heat. The greater the amplitude of the molecular motion of two
bodies, in- so-called contact with each other, the more imminent is the
collision of their atoms. An augmentation of temperature increases
the amplitude of this molecular motion ; hence, heat usually promotes
chemical combination. In some cases, the molecular motion of two
bodies, at ordinary temperatures, is sufficient to bring them into col-
lision ; hence, what is termed " spontaneous combustion " (e. g., phos-

142 ANNUAL OF SCIENTIFIC DISCOVERT.

phorus burns in air, potassium in water, etc.). In regard to the
spontaneous combustion of the human body, Professor Frankland
showed that it was a physical impossibility, on account of the large
amount of water in its constitution.

Gunnery and the Dynamical Theory of Heat. In an address at the
opening of the British Association, 1863, Sir W. Armstrong stated,
" that the science of gunnery was intimately connected with the dy-
namical theory of heat. When gunpowder is exploded in a cannon,
the immediate effect of the affinities, by which the materials of the
powder are caused to enter into new combinations, is to liberate a force
which first appears as heat, and then takes the form of mechanical
power communicated in part to the shot and in part to the products of
explosion which are also propelled from the gun. The mechanical
force of the shot is reconverted into heat, when the motion is arrested
by striking an object, and this heat is divided between the shot and the
object struck, in the proportion of the work done or damage inflicted
upon each. These considerations recently led me, in conjunction with
Captain Ncble, to determine experimentally, by the heat elicited in the
shot, the loss of effect due to its crushing when fired against iron plates.
Joule's law, and the known velocity of the shot, enable us to compute
the number of dynamical units of heat representing the whole mechani-
cal power in the projectile, and by ascertaining the number of units de-
veloped in it by impact, we arrived at the power which took effect
upon the shot instead of the plate. These experiments showed an
enormous absorption of power to be caused by the yielding nature of
the materials of which projectiles are usually formed; but further ex-
periments are required to complete the inquiry."

THE EFFECT OF INTENSE HEAT ON LIQUIDS.

At a recent meeting of the London Chemical Society, Mr. Grove, in
a paper on the above subject, first called attention to the difference ex-
isting between the boiling of water, under ordinary circumstances, and
that of sulphuric acid. He stated that the equable evolution of steam,
when water is boiled in an open vessel, is caused by the presence of a
certain amount of air dissolved in the water, and that boiling may be
regarded .as an evaporation into the liberated bubble of air set free by
the elevated temperature. In an open vessel, a sufficient amount of air
is continually reabsorbed, so that the ebullition goes on equally. On
the contrary, when water is heated in a very long tube, it boils in the
first instance evenly, but after the air is expelled it boils with the most
violent concussions ; during the regularly-recurring intervals between
the sudden and violent emissions of steam, the temperature rises far
above 212, and then a sudden explosive production of steam occurs,
almost resembling the discharge of gunpowder. By placing a portion
of water in a flask under the vacuum of a good air-pump, and heating
it by the transmission of a strong electric current, passed through a
fine platinum wire contained in the water, Mr. Grove proved that the
water did not boil at all, but that the whole burst up into violent con-
cussions at regularly-recurring intervals. When the air was exhausted,
ebullition occurred at intervals of about a minute, upon which a burst
of vapor would almost eject the contents of the flask. On this action's
increasing, the water would again become perfectly tranquil, and re-

NATURAL PHILOSOPHY. 143

main so for a minute, when another tumultuous ebullition would occur,
to be succeeded by a period of rest ; and the same phenomena would
be repeated at such regular intervals that the apparatus might almost
serve as an indicator of time. If a thermometer were placed in the
flask, it would be found that the temperature alternately rose and fell
some few degrees. Indeed, it could not be asserted that the boiling

^3 '

point of water was constant, for it depended upon the amount of air in
solution ; and Mr. Grove believed that no one had yet succeeded in ob-
serving the boiling point of absolutely pure water.

Mr. Grove suggested that the phenomena of the Geysers, or inter-
mittent explosive fountains of Iceland, would admit of a more satisfac-
tory explanation by reference to these facts than on the supposition of
the existence of complicated subterranean chambers.

In the course of his experiments, Mr. Grove ascertained that it was
almost impossible to free water from gaseous bodies ; and, as a proof of
this, he cited the following experiment : A long glass tube closed at one
extremity, was bent in the middle to nearly a right angle ; the closed
limb was then half-filled with water, from which, by long boiling, the
air was supposed to have been expelled : the remaining space in the
tube was then completely filled with olive oil, and the open extremity
was dipped into a small basin of the same. Heat was then applied to
the tube until the water boiled, and this temperature was maintained
for a considerable time. Each bubble of steam which left the surface
of the water passed through the column of oil, becoming smaller and
smaller during its ascent ; but it never condensed without leaving a
microscopic bubble of gas, which at length accumulated to such an ex-
tent that it could be examined. It was found to consist of pure nitro-
gen ; and he had never succeeded in expelling the whole of this gas
from the water. The evaporation of nineteen-twentieths of the water
did not secure the remainder from being mixed with nitrogen. On
boiling ordinary water, air containing a slightly-increased proportion of
oxygen was first driven off, the oxygen gradually diminishing until pure ,
nitrogen was expelled. The avidity with which such water again ab-
sorbs air is remarkable. In the expressive words of Mr. Grove, " it
sucks it up again almost as a sponge takes up water." By a slight
modification in the apparatus, the experiment was repeated with mer-
cury, instead of oil, in contact with the boiling water. It furnished a
similar result.

A number of facts regarding the solubility of gas in water were
finally enumerated. The general conclusion drawn from the experi-
ments, was to the effect that water had a very powerful affinity for the
gases of the atmosphere ; that the oxygen could be eliminated by seve-
ral processes, but the nitrogen resisted all attempts to expel it from
solution ; so much so that it might be doubted whether .chemically pure
water (i. e., a compound of the two elements, oxygen and hydrogen,
only), had ever been prepared ; and, further, that ebullition (as applied
to water), under all circumstances, consisted merely in the production
and disengagement of bubbles of aqueous vapor, formed upon a nucleus
of permanent gas. The question, therefore, was raised as to whether
nitrogen is so absolutely inert a body as had formerly been supposed.

144 ANNUAL OF SCIENTIFIC DISCOVERT.

JOULE'S NEW SENSITIVE THERMOMETER.

At a recent meeting of the Manchester Philosophical Society, Dr.
Joule exhibited an exquisitely sensitive air thermometer, capable of
being affected by the y-gVo" f a centigrade degree of heat. The con-
struction is thus described : A glass vessel in the shape of a tube, two
feet long by four inches in diameter, is divided longitudinally by a
blackened pasteboard diaphragm, leaving spaces at the top and bottom,
each little over an inch. In the top space, a piece of magnetized sew-
ing needle, furnished with a glass index, is suspended by a single fila-
ment of silk. It is evident that the arrangement is similar to that of a
bratticed coal-pit shaft, and that the slightest excess of temperature on
one side over that on the other must occasion a circulation of air, which
will ascend on the heated side, and, after passing across the fine glass
index, descend on the other side. It is also evident that the sensibility
of the instrument may be increased to any required extent, by dimin-
ishing the directive force of the magnetic needle. I purpose to make
several improvements in my present instrument ; but in its present con-
dition, the heat radiated by a small pan, containing a pint of water
heated 30, is quite perceptible at a distance of three yards. A further
proof of the extreme sensibility of the instrument is obtained from the
fact that it is able to detect the beat radiated by the moon. A beam
of moonlight was admitted through a slit in the shutter. As the moon
(nearly full) travelled from left to right, the beam passed gradually
across the instrument, causing the index to be deflected several degrees,
first to the left and then to the right. The effect showed, according to
a very rough estimate, that the air in the instrument must have been
heated by the moon's rays a few ten-thousandths of a degree, or by a
quantity, no doubt the equivalent of the light absorbed by the black-
ened surface, on which the rays fell.

CHANGE OF FORM IN METALS BY IRREGULAR COOLING.

Colonel H. Clerk has communicated to the Royal Society some curi-
ous experiments on this subject. It appears that a wheel had to be
shod with a hoop-tire, which was required to have a bevel of about
f ths of an inch, and one of the workmen suggested that this could be
accomplished by heating the tire red-hot, and immersing one-half its
depth in cold water. This was done, with the predicted result ; the part
out of the water being reduced in diameter. A series of experiments
followed, with similarity of action, the cylinders always exhibiting a
contraction above the water-line, followed, if they were sufficiently high
out of the water, by an expansion corresponding to that below the fluid.
The explanation given is, that the parts under the water cooled quick-
ly, and those above it slowly. If no cohesion had united the two parts,
both would have obtained the same diameter, one first, and the other
afterwards ; but as the cohesive power of cast-iron, or other metal, is
great, the under part tends to pull in the upper, and the upper to pull
out the under. In this contest, the cooler metal, being the stronger,
prevails, and so the upper part gets pulled in, a little above the water-
line, while still hot. But it has still to contract in cooling, and this it
will do to the full extent due to its temperature, except so far as it may
be prevented by its connection \vilh the rest. Proceedings of the
Royal Society.

NATURAL PHILOSOPHY. 145

IGNEOUS CONDITION OF MATTER.

In a recent work " On Matter and Ether ; or, the Secret Laivs of
Physical Change" by Thomas Birks, M. A., Cambridge (England),
1862, the author, in a chapter entitled the "Igneous Condition of
Matter," sets forth" the following views : " According to the present
theory of the laws of matter, there may be more truth than has latterly
been recognized in the old arrangement of the four elements, which
placed a fourth region of fire above the solid, liquid, and gaseous con-
stituents of our globe. In fact, above the region where the air, though
greatly rarefied, is still elastic, there must be a still higher stratum
where elasticity has wholly ceased, and where the particles of matter,
being very widely separated, condense around them the largest amount
of ether. All sensible heat, in the collision or oscillation of neighboring
atoms of matter, will thus have disappeared ; but latent heat, in the
quantity of condensed ether or repulsive force ready to be developed
on the renewed approach of the atoms, will have reached its maximum,
and may be capable of producing the most splendid igneous phenomena,
like the northern lights, or tropical thunder-storms."

THE FORMATION OF SMOKE-RINGS.

Mr. W. B. Tegetemeir, in the London Intellectual Observer, in an
article on the production of " smoke-rings," such as are produced by
the spontaneous combustion of phosphuretted hydrogen, and by practised
tobacco-smokers, describes an interesting method by which these rings
can be produced at pleasure by mechanical means. He says, " If six
ordinary, oblong cards, each about three inches by four, are taken and
the ends folded down, after being partially cut through, so as to leave
a central square, as here shown, they may with a
Httle dexterity be combined into a very pretty
cubical box. Previous to being put together, a
circular hole about the size of a fourpenny-piece
should be cut in one card. If the box so con-

structed be filled with any dense smoke, such as that from a tobacco-
pipe, or by allowing vapors of hydrochloric acid and ammonia to enter
together, smoke-rings, in any number, and at any desired rate of suc-
cession, may be caused to issue from the hole in the box, by the slight-
est series of gentle taps on one of the sides. Their production in this
manner is so facile, and so perfectly under control, that their formation
constitutes if the experiment be performed in a room in which the
air is perfectly still a very interesting and pretty experiment.

" So much for the mode of producing these rings. Now let us con-
sider their construction. If the reader has ever observed an ascending
column of smoke, on a perfectly calm day, he cannot fail to have been
struck with the extreme beauty of its form, rising, perhaps, from the
summit of one of those tall factory chimneys, now, alas, so smokeless*!
It ascends perpendicularly, spreading out as it rises, and gradually as-
suming the form of an elongated convolvulus, or, to use a less poetical
and more homely comparison, that of a long funnel. This spreading
out is due to the resistance of the air, which is greater, being more con-
centrated, toward the centre than at the outside.

" If the reader can imagine the emission of smoke to be intermittent,
instead of continuous, it is obvious that this expanding column would be

13

146 ANNUAL OF SCIENTIFIC DISCOVERY.

broken up into rings, the constantly enlarging circular form of which
would be due to the same cause as that which produces the enlargement
of the column, namely, the greater pressure of the air in the centre.
That this is the case will be evident on a close inspection of a single
ring, when it will be found to consist of a vast number of rapidly ro-
tating circles, arranged on a circular axis. Let us imagine a number
of common, circular, bone button-moulds, each with a single hole
through its centre, strung on a piece of wire, which is then bent in a
circular form. This would give a correct idea of the structure of a
smoke-ring ; and if we imagine, further, each of these bone moulds rota-
ting downward and inward, as the ring rises and expands, the resem-
blance would be still more complete."

PHENOMENA OF SOUND.
The following is an abstract of a recent lecture before the Roval In-

O /

stitution, London, by Prof. Tyndall, on the " phenomena of sound : "
He began by showing how musical sounds can be produced by caus-
ing water to flow through small apertures, these sounds being probably
due to the viscosity of the liquid, causing it to create tremors in the or-
ifice. He then proceeded to consider and exemplify the phenomena of
resonance in open tubes, the cavity of the mouth being adduced as an
instance, as in the case of the jewsharp, which thereby becomes a mu-
sical instrument. The human voice, it was also stated, is produced by
a reed instrument, the reeds being vibrating membranes, which can be
tightened so as to vary the pitch (as has been made visible by Czer-
rnak's remarkable apparatus, the Iaryngos3ope). Vibrating reeds, or
tongues, also produce the sound in the concertina and harmonica, and
are also associated with organ pipes. The latter part of the lecture
was devoted to the consideration of the phenomena of interference, and
discord or dissonance, in accordance with the following principles, based
on the researches of Young, Wheatstone, Savart, and other philoso-
phers. The sonorous shocks communicated to the ear by two tuning-
forks slightly out of unison are termed beats, which succeed each other
more rapidly as the departure from perfect unison augments, their
number, in a given time, being equal to the difference in the number of
vibrations executed in that time by the sounding bodies. When the
beats were slow, they could be counted with ease ; but when exceeding-
ly rapid, they manifested themselves to the ear by the roughness which
they impart to the sound ; the roughness is the cause of dissonance.
Professor Tyndall concluded his lecture by exhibiting some of Lissa-
jous's remarkable acoustic experiments, by means of tuning-forks, mir-
rors, and the electric lamp. It having been proved that a tuning-fork
does not emit sound with the same intensity in all directions, and that
the sounds of two tuning-forks which vibrate exactly at the same rate
Wend together ^o as to give the impression of a single sound, it was
next shown that if one tuning-fork vibrate a little more rapidly than
the other, at certain times both forks conspire to augment the sound,
and at other times they act in opposition to each other. The conse-
quence being an intermittent effect, composed of successive periods of
sound and silence. When two sounds thus neutralize each other, the
effect is technically called interference. It was also shown how, by the
stifling of a portion of the vibrations of a sounding disk, we can aug-
ment the sonorous intensity.

NATURAL PHILOSOPHY. 147

Propagation of Sound in the Air. Newton was the first to study the
propagation of motion in the atmosphere, and the solution which he
gave still excites the admiration of geometers, and is termed by Laplace
" a monument of his genius." Sometimes, however, it does not entirely
agree with experience ; for instance, it gives for the swiftness of propa-
gation a value of about a sixth below that given by observation. Since
his time Lagrange, Euler, Laplace, Poisson, and other geometers, have
occupied themselves with this problem with the view of either estab-
lishing the true mathematical theory, or discovering the cause of the
difference between calculation and experience. The subject has also
been taken up by the eminent mathematician Duhamel, who has laid
a memoir before his associates of the French Academy, giving his cal-
culations, whereby he arrives at this singular consequence, "that the
theoretic swiftness of sound in the air, supposing that there is no eleva-
tion of temperature, is identical with that given by experience." The
hypothesis of an elevation of temperature, which appears so probable,
and which comes so conveniently to the assistance of the theory, be-
comes a difficulty, and we find ourselves compelled either to demon-
strate that this hypothesis is not legitimate, or to find a new and hith-
erto unknown cause which shall neutralize the effect.

Transmission of Sound to a great Distance. Dr. F. C. Robinson,
of Greensburg, Westmoreland County, Pa., says that the report of ar-
tillery at the battle of Gettysburg, on the 3d of July, was distinctly
heard at Greensburgh, a distance of one hundred and twenty-five miles
from the seat of conflict ; on lying down on the ground, jarring could be
distinctly felt. Dr Robinson says, " That the whole neighborhood
claim to have heard the firing. During Friday, the air was~cahn and
the sky cloudless."

Function of the Ear. Prof. Helniholz regards the snail-shell, or
cochlea, as the special organ for transmitting musical sounds to the
nerves, while noises affect other portions of the ear. The so-called
"fibres of Corti," of which there are about three thousand, he considers
each capable of being affected by a simple sound, while a compound
sound acts upon several, and produces a corresponding impression on
the nerves. Each filament of the acoustic nerve is united to an elastic
filament, which he supposes to be thrown into vibration by appropriate
sounds.

VIBRATING WATERFALLS.

The American Journal of Science and Arts, for November, 1863, con-
tains an article, by Prof. E. Loomis, discussing anew the subject " vibrat-
ing waterfalls" and detailing observations on three vibrating water-
falls, namely, in South Natick, Holyoke, and Lawrence, Mass. In 1843,
Professor Loomis published an article on this same subject, in which he
suggested that the dam itself was the vibrating body, and that the vi-.
brations were analogous to those of a stretched cord. Prof. Snell, of
Amherst, however, differed from such a conclusion, and in turn attribut-
ed the cause of the vibrations to a column of air behind the sheet of
water falling from the dam. Prof. Loomis, after an extended series of
observations, has apparently abandoned his original views, and arrived
at conclusions similar to those of Prof. Snell. A series of careful obser-
vations were made, in 1862, by Mr. William Edwards, at the request of

148 ANNUAL OF SCIENTIFIC DISCOVERT.

Professor Loomis, on the vibrations of a dam at South Natick, Mass.
These resulted in ascertaining that the time of a vibration, according
to the depth of water on the edge of the dam, was a little less than the
time in which a solid body would fall through a space equal to the
depth of the water. Thus, when the depth of water was 5.06 inches,
the time of one vibration was 0.138 of a second, while the time of a
solid body falling through that depth was 0.162 of a second.

The dam across the Connecticut River, at Holyoke, Mass., is 1017
feet long, and 30 feet high. It is formed of square timbers inclined 22
degrees to the horizon. From the crest of the dam, the water descends
along an apron about four feet in length, sloping downward at an angle
of 22 degrees. The sheet of water falling over this dam exhibits three
different rates of vibration, namely, about 256, 135, and 81 vibrations per
minute, corresponding to depths of 16, 28, and 56 inches of water on
the dam. The change from the first to the second rate of vibration
takes place when the depth of water is from 23 to 26 inches ; and the
change from the second rate to the third takes place when the depth is
from 35 to 4 7 inches. The vibrations are not noticed when the depth
of water is less than about 1 2 inches, and they also disappear when the
depth is as great as 80 inches.

At Lawrence, Mass., Mr. B. Coolidge, engineer, made a series of ob-
servations, as also did Prof. Loomis. In all these, the time of the vibra-
tions was taken, and compared with the time which a solid body would
occupy in falling from the same height ; and the number of vibrations
of a column of air of the depth behind the sheet of falling water has
been calculated. Now, as to the conclusions, Prof. Loomis says, " I
do not know of any theory which will enable us to compute the precise
influence of a sheet of water of given dimensions ; but at present, it
seems probable that the vibratory motion originates in the column of
air behind the sheet of water, and that the descending sheet serves
merely as a load to retard the velocity of these vibrations." When the
edge of the dam is uneven, and when the sheet of water is very thin,
an opening will be left for the column of air behind the sheet, and no
vibrations are produced. In reference to this point, Prof. Loomis
says, " It is believed that most waterfalls exhibit some decree of vi-

/ * ^^

bratory motion, at certain stages of water; but in order that these
vibrations may be powerful and long-continued, the edge of the dam
must be horizontal, and quite smooth ; otherwise, the thickness of the
descending sheet will not be uniform ; and the sheet will swell into
ridges in some places, while other parts become thin. The sheet will
divide in some places before reaching the bottom of the fall, and this
leaves an opening in the enclosure which contains the column of vibrat-
ing air. This is probably the reason why many waterfalls never ex-
hibit this phenomenon in a palpable manner ; and why, in only a few
cases, is the vibration so powerful as to cause any annoyance."

The answer to the question, Why the vibrations vary or disappear
with variations in the height of the water is given as follows : " The
descending sheet of water must have a thickness of several inches ; oth-
erwise, it is divided by the action of the air, and the column of air
ceases to be enclosed on all sides. With a fall of nine feet, as at South
Natick, a thickness of four or five inches is requisite ; and with a fall
of thirty feet, as at Holyoke, a thickness of nearly a foot is requisite.

NATURAL PHILOSOPHY. 149

At Lawrence, with a fall of thirty-four feet, the vibrations are not no-
ticed when the depth of water is much less than three feet ; but this
seems to be owing to the inequalities on the top of the darn. The vi-
brations cease almost entirely when the water exceeds a certain height
because the thickness of the sheet becomes too great in comparison with
its height, and there being some cohesion between the particles of the
liquid, the sheet partakes somewhat of the rigidity of a solid body. In
order to produce a strong effect, the thickness of the sheet must not ex-
ceed about one-sixth or one-eighth of the height of the fall. At South
Natick, with a fall of nine feet, which is somewhat diminished by the
back- water at the time of a freshet, the vibrations cease when the depth
of water much exceeds ten inches. At Holyoke, with a fall of thirty
feet, which is also diminished by the back-water at the time of a fresh-
et, the vibrations cease when the depth of water much exceeds five
feet. At Lawrence, also, where the fall is a h'ttle greater than at
Holyoke, the vibrations cease when the depth of water, on the crest
of the dam, much exceeds five feet."

According to these views, all dams may be built so as to avoid jarring
vibrations.

SCIENTIFIC BALLOON ASCENSIONS.

Under the auspices of the British Association, the balloon ascensions
inaugurated in 1862, for scientific observation and experiment, have
been continued during the past year by Mr. Glaisher the well-known
British meteorologist, and the former aeronaut, (see Annual Sci. Dis.
1863, pp. 137-144.) At the last meeting of the Association, this gentle-
man gave the following resume of the facts and deductions arrived at in
his recent ascensions :

On ascending with a cloudy sky, the temperature usually declines till
the clouds are reached ; but on breaking through them, there is always
an increase of several degrees of temperature ; and after this the de-
cline of temperature usually continues, and would do so continuously
if there were no disturbing causes in operation. On ascending with a
clear sky, we start with a "higher temperature than with a cloudy one
as much higher as the loss of heat caused by the clouds ; an approxi-
mate measure of which is that sudden increase of temperature in passing
from cloud to a clear sky. In no instance have I met with the atmos-
phere in a normal state in respect to temperature ; at different eleva-
tions even up to four or five miles, warm currents of air have been met
with. By warm, I mean 'that their temperature was higher than in the
stratum beneath. These warm strata are variable in thickness, from
1,000 feet to 10,000 feet, and varying from 1 to 20 in excess. It is
necessary, in considering the law of the decrease of temperature, to
take into account the state of the sky, and to separate the experiments
made in one state from those in the other. The results in the cloudy
state do not at all confirm the theory of a decline of 1 of temperature in
300 feet. If we now consider the decrease at heights above the cloud
plane, the decrease of the temperature of the air, at heights exceeding
5,000 feet, the results follow almost in sequence with those found
with a partially clear sky, and show that an average change takes
place of 1 of temperature in 139 feet near the earth and that for a
change of 1 at the height of 30,000 feet, we have to pass through at
13*

150 ANNUAL OF SCIENTIFIC DISCOVERT.

least 1,000 feet. If we now take the whole decrease of temperature
with elevation, we shall have the following results: From the ground
to 1,000 feet 7.2, or 1 in 139 feet. About 14,000, the average is the
same as would be given by using the mean as found from observations
on mountain-sides, namely 1 in 300 feet ; but at heights less and greater
than 14, 000' feet the space is less or greater than 300 feet. It is cer-
tain, then, in any balloon ascent, between 8,000 and 20,000 feet, if
the temperature on leaving the earth, and at the highest elevation,
were only used, that the results, 1 in 254 feet in the former, and 1
in 355 in the latter, would have been looked upon as generally con-
firming the theory of a decline of 1 in 300 feet, and hence the ne-
cessity of noting the temperature on leaving the earth, as frequent-
ly as possible afterwards, and extending the observations to the
highest point possible. It would appear from the results obtained
that the decline of temperature is largest near the earth, smallest at
the highest elevations, and intermediate with increasing spaces for the
same decrease of temperature, in these respects agreeing, therefore,
with the general law, as formed from the extreme high ascents. This
law seems to me more natural and consistent than a uniform rate of
decrease could be, received as a physical law, up even to moderate
elevations. But I have reasons to believe that the amount of change
is different at different seasons of the year, and I think it is different
during the night from that during the day. And it seems certain that
these Jaws will not hold good for all countries, although they probably
will for very large tracts of country. I have reason to believe they
will not hold good in India.

From all the experiments made in the year 1862, it was found that
at the earth's surface there were upon the average very nearly five
grains of water in a cubic foot of air, in the invisible shape of vapor,
or l-50th part of a cubic inch of water ; or a cube of water whose
sides were a quarter of an inch nearly. This value decreased grad-
ually to one-half at the height of 5,000 feet, where there was only
l-100th of an inch of water in a cubic foot of air. At the height of
10,000 feet this amount was reduced to less than 1^ grain ; at 15,000
feet high there was only 9-10ths of a grain, or l-2SOth part of a cubic
inch; at 20.000 feet, this was reduced to half a grain; and at 25,000
feet to 1-1 Oth only of a grain or to a drop of water, = l-2530th part of a
cubic inch, being l-50th part only of the water at the surface of the
earth ; in other words, about a drop of water but little more than 1-
100th of an inch in diameter. But the actual amount met with on any
ascent will most probably differ from these results, as, like the temper-
ature of the air, the diffusion of water seems to be very rarely in a
normal state. The amount of water in the air at the same height
seems to be constantly varying, and to be affected with diurnal
changes, so that on comparing the moisture shown at one ascent with
that experienced in another, the time of day at which the experiments
were made will have to be considered. I have been speaking of the
amount of water actually present in the air. This information, with-
out reference to temperature, gives no'idea of the moisture of the at-
mosphere, since a capacity of air for moisture doubles itself for an in-
crease of about 20 of temperature ; a clearer idea of the relative
moisture at different heights will be given, by considering that amount

NATURAL PHILOSOPHY. 151

of water in the air which would saturate it as divided into 100 parts,
and then ascertaining how many of these parts are present. From all
the experiments treated in this way, the laws of moisture thus expressed
are, with an overcast sky, almost uniform degree of humidity to the
height of 3,000 feet or 77 out of the 100 parts then a rather sud-
deif decrease to 80, and to 83 at 5,000 feet. With a partially clear
sky, the laws of moisture show a humidity on the ground, with 15 out
of 100 parts more than in partially clear skies, and of 14 at 5,000 feet.
Above 5,000 feet, the humidity decreases to 10 at 25,000 ; that is, low-
as the temperature there is, 10, out of the 100 possible to be present, at
the temperature, is all that is present. Higher than this, there would
seem to be an almost entire absence of aqueous vapor. These seem
to be the general laws ; but, as I have before remarked, the regular
dimensions are frequently interrupted, and strata of moist air may ex-
ist at great elevations.

As regards the blue color of the sk?j, Mr. Glaisher was inclined to at-
tribute the phenomena to reflection of light from the molecules of air,
and not, as some have supposed, to reflection from the thin pellicle of
water forming the vesicles of vapor floating in the air ; inasmuch as
the blue was found to be brightest at the greatest heights (six and
seven miles) attained to by the aeronaut, where the air is almost de-
prived of moisture.

In an ascent made in a rain-storm on the 2 7th of July, Mr. Glaisher
directed his attention particularly to observe whether there was a
stratum of cloud at a certain elevation above that from which the rain-
drops fell ; and also as regards the size of the drops at different eleva-
tions. The conclusions arrived at were, that whenever rain is falling
from an overcast sky, there is a second stratum above ; but with an
overcast sky and no rain, then the sun is shining on the upper surface
of the clouds. In regard to the second point, he says, " The size of
the rain-drops, as they fell on my note-book before starting, was fully
as large as a four-penny piece ; they decreased in size on ascending ;
but our upward movement was too quick, and we soon passed out of
rain. On descending from above the clouds, we first encountered a
dry and then a wet fog ; passed into that which may be described as
damp air or exceedingly fine rain ; then experienced very fine but de-
cided drops of rain, like pins' points, covering the note-book ; these in-
creased in size on approaching the earth, but more rapidly when very
near the earth. The drops of rain, on returning to the earth, were as
large as those noted on leaving ; and rain had been falling heavily all
the time we were in the balloon." Another curious fact elicited in
these ascensions is that the action of the sun's rays upon " sensitized"
photographic paper is much less at great altitudes than near the earth's
surface. In an ascension made April 21st, 1863, Mr. Glaisher took
with him slips of such paper, and arranged that similar slips should be
exposed at Greenwich Observatory, and the amount of coloration not-
ed simultaneously every five minutes. In his report, he states that the
paper in the balloon was exposed to the full rays of the sun, with this
extraordinary result, that at three miles high the paper did not color
so much in half an hour as in the grounds of the Royal Observatory in
one minute ; a fact which would seem to indicate that the chemical
eifects of li^ht are largely due to its passage through the atmosphere,

152 ANNUAL OF SCIENTIFIC DISCOVEEY.

i

or at least to the density of the atmosphere through which it has re-
cently passed."

In this same ascent, observations were made on the solar spectrum,
especially upon the fixed lines of the spectrum. The number of lines
visible seemed to be innumerable, and the conclusion arrived at is thus
given : " The number of lines in the solar spectrum appear to be in-
creased when viewed from a position above the clouds, and therefore
none of the lines as viewed from the earth would seem to be atmos-
pheric."

The most extraordinary ascent was made in the month of June
1863, of which Mr. Glaisher's record is as follows:

" We left the earth at Ih. 5m. p. M. ; at Ih. 9m. we were at the height
of two thousand feet; at Ih. 15m. we passed above eight thousand
feet; a height of eleven thousand feet was reached at Ih. 17m.; in
nine minutes afterwards, we were fifteen thousand feet from the earth,
and rose gradually to about four and a quarter miles at Ih. 55m. ; on
descending, at 2h., we were twenty thousand feet from the earth ; at 2h.
13m. about fifteen thousand; at 2h. 17m. ten thousand; at 2h. 22m.
five thousand ; and on the ground 2h. 2Srn. Before starting, the tem-
perature of the air was sixty-six degrees. It decreased rapidly on
leaving the earth ; it was fifty-four degrees at three thousand feet high,
forty-nine degrees at four thousand feet, forty-one degrees at one mile,
thirty degrees at two miles ; and, up to this time, every succeeding
reading was less than the preceding. But here the decrease was
checked ; and, while passing from two to three miles, the temperature
at first increased to thirty-two degrees, then decreased to twenty-nine
degrees. A second increase followed, and at the height of three and
a quarter miles the temperature was thirty-five degrees. A rapid de-
crease then set in, and at three and a half miles the temperature was
twenty-two degrees. From this time till the height of four miles was
reached, the temperature varied frequently between twenty-two de-
grees and eighteen degrees, and at the height of four and a quarter
miles, the lowest temperature took place namely, seventeen degrees.
On descending, the temperature increased to twenty-six degrees, at the
height of twenty-three thousand feet, and then to thirty-two degrees,
at the height of four miles ; it then decreased nine degrees in one min-
ute to twenty-three degrees. It continued at this value for some time,
then increased slowly to twenty-nine degrees at nineteen thousand
feet. It continued almost constant for a space of two thousand feet,
then increased to thirty-two degrees at fifteen thousand feet ; and was
thirty-two degrees or thirty-three degrees, almost without variation,
during a snow-storm which we experienced from thirteen thousand
five hundred feet to ten thousand feet, where an increase set in ; at
five thousand feet, the temperature was forty-one degrees, and sixty-
six degrees on the ground."

At a height of two miles the sighing or rather moaning of the
wind was heard, as preceding a storm, and was the first instance in
which Mr. Glaisher had heard such a sound at such a height. It was
not owing to any movement of the cordage of the balloon above, but
seemed to be below, as from conflicting currents beneath. " At the
highest point reached, about four and a quarter miles, the sky was very
much covered with cirrus clouds, and its color, as seen through the

NATURAL PHILOSOPHY. 153

breaks in the clouds, was of a pale blue, such as is seen from the
earth through a very moist atmosphere. We were above clouds, but
there were no fine views or forms, all was dirty-looking and confused,
the atmosphere being thick and murky.

"At the height of three miles a train was heard, and at four miles
another. These heights are the greatest at which sounds have ever
been detected, and indicate the generally moist state of the atmos-
phere."

Mr. Glaisher concludes : " This ascent must rank amongst the
most extraordinary ever made. The results were most unexpected.
We met with at least three distinct .layers of cloud on ascending, of
different thicknesses, reaching up to four miles high, when here the
atmosphere, instead of being light and clear as it always has been in
preceding ascents, was thick and misty ; but perhaps the most ex-
traordinary and unexpected result in the month of June was meeting
with snow and crystals of ice in the atmosphere at the height of three
miles, and of nearly one mile in thickness."

ASCERTAINING THE HEIGHT OF CLOUDS.

At the British Association, 1863, Prof. Chevallier gave the following
description of an instrument of his invention, designed to ascertain the
height of clouds. It consisted, he said, of two jointed rulers, graduated
from the centre of the joint, and one of them furnished with an up-
right sliding-piece, with an opening to allow the sun's light to pass, the
edge of which is at a known distance by the scale from the ruler on
which the piece slides. If, then, the distance in miles or yards at which
the shadow of a cloud is cast upon the earth be known, by laying one
branch of the ruler toward the shadow of the cloud and the other in
the direction of the vertical line from the part of the cloud which casts
the shadow directly on the earth beneath the cloud, and then moving
the sliding-piece along this latter branch of the ruler until the shadow
of the edge of the opening just reaches the middle of the rod laid in the
direction of the shadow of the cloud, you have on the ruler and the
sliding-piece an exact representation in miniature of the actual circum-
stances of the cloud, and a simple rule-of-three calculation gives the
vertical height of the cloud above the earth. Thus, " multiply the
distance of the shadow of the cloud (supposed to be known) by the
height of the sliding-piece, and divide by the distance of the shadow of
the^sliding-piece from the angle of the rulers, and the quotient is the
height of ^the cloud required."

OBSERVATIONS ON WINDS.

Prof. Dove, the celebrated meteorologist of Berlin, in the second edi-
tion of his Law of Storms, recently published by the Longmans, of
London, thus explains his so-called " Laws of Gyration," or the rota-
tion of the wind in relation to the rotation of the earth. He says,
" In the northern hemisphere, when polar and equatorial currents suc-
ceed each other, the wind veers in general in the direction S., W.,
N., E., S., round the compass. Exceptions to this rule are more com-
mon between S. and W. and between N. and E., than between W.
and N. or between E. and S.

" In the southern hemisphere, when polar and equatorial currents

154 ANNUAL OF SCIENTIFIC DISCOVERT.

succeed each other, the wind veers in general in the direction S., E.,
N., W., S., round the compass. Exceptions to this rule are more com-
mon between N. and W. and between S. and .E., than between "W.
and S. or between E. and N.

" This is the phenomenon which I have termed THE LAW OF GYRA-
TION."

The trade-winds and monsoons are special causes of this law. Pro-
fessor Dove enters into a minute examination of the phenomena of the
first, dividing what he calls the permanent winds into the under and
upper trade-winds. Both, he is disposed to regard, as imperfectly de-
veloped monsoons, the word monsoon being as he shows, derived
from the Arabic mausim, or season. This is confirmed by the fact that
where monsoons exist, there are but two oscillatory movements of the
atmosphere annually ; monsoons being polar and equatorial currents,
alternately, according to the season of the year ; so that their directions
in the northern hemisphere are N. E. and S. W., and in the southern
S. E. and N. W. Violent as monsoons generally are, they are tame
in comparison to cyclones, which are truly terrible. Fortunately, the
area of these hurricanes is comparatively limited, being confined to
the West Indian seas ; their usual course being in a parabolic curve,
having some point near Bermuda for its focus originating in the
Gulf of Florida and running along the coast of the United States,
following generally the course of the Gulf-stream. Cyclones, as their
name imports, are strictly rotatory, and they never deviate from the fol-
lowing rules. Cyclones in the northern hemisphere possess a motion
that is retrograde, or in the contrary direction to the hands of a watch,
whereas, those occurring in the southern hemisphere have a converse
motion. On the equator itself cyclones never occur. According to
Professor Dove, they are

" Most common in the district between the S. E. trade-wind and
the N. W. monsoon, which is called the region of the ' variables.'

44 The rotatory motion takes place in the direction from E. through
S. toward W. and N. The intensity of the cyclone increases regu-
larly toward its centre. At the centre itself there is a dead calm, and
the greatest violence of the storm is experienced at the edge of this
calm circle. The diameter of this circle is greatest when the storm is
just commencing. If the rotatory motion increases in violence, the di-
ameter of this circle is decreased to about ten or twelve English miles.

^D

" The advance of the cyclone, up to lat. 20 S., is at the rate of 200
to 220 miles in the twenty-four hours. From that point it becomes
less rapid up to the outer edge of the S. E. Trade. The direction of
the advance is from lat. 10 S.,near the Indian Archipelago, to lat. 28
or 30 on the east coast of Africa ; first toward W. S. W., then to-
ward S. W. by S., and lastly toward S. S. W.

" Throughout the whole of the cyclone, torrents of rain fall, which
arc more violent in front of it than behind it. The clouds are dark,
massive, and lead-colored, as the centre is approaching. Electrical ex-
plosions are most frequent on that side of the cyclone which is nearest
to the equator. The sea is disturbed irregularly to the distance of 300
or 400 miles during every such storm. The barometer falls rapidly as
the centre of the cyclone approaches, but the lowest level appears to
occur a little before it passes."

NATURAL PHILOSOPHY. 155

Direction of the Wind. Professor Airy has observed some curious
facts respecting the direction of the wind. It seems that there are
only eight points of the compass from which the wind ever blows stead-
ily ibr any length of time, namely, the S. S. W., the W. S. W. a point
between the W. and N. W., another between the N. and E., another
between E. and S. S. W., theN., the W., and the E. The wind never
blows directly from the south.

PRESSURE OF THE ATMOSPHERE, OCEAN, ETC.

The following novel views respecting the pressure of the atmosphere,
and of the waters of the ocean at varying depths have been communi-
cated by Mr. C. E. Townsend, Esq., of Tompkinsville, N. Y. :

According to the philosophy of the day, the pressure of the atmos-
phere at sea-level is calculated at fifteen pounds for every square
inch, being equal to a column of water one inch broad and thirty-
three feet in height , and every thirty-three feet descent into the ocean
adds an additional fifteen pounds pressure, over every square inch,
thus augmenting the density of parts beneath in proportion to the
superincumbent pressure. Recent discoveries prove that a high order
of radiate animals and fleshy inhabitants of shells, in vast numbers,
are found living at the bottom of the ocean one and a hah miles
down.

In a paper from Dr. I. C. Wallack, in the Scientific Annual for
1862, page 344, Professor Agassiz, is made to say " that animals sub-
ject to such enormous pressure, to avoid being crushed by the weight,
from depths at fifteen pounds for every thirty-three feet descent, must
admit water very freely through their tissues." Surely such explana-
tion must be unsatisfactory, for the animal tissues remaining, they could

little heavier than surface water, is supposed to sink to the bottom,
whatever that depth may be, and to enable it to do so, in accordance
with the above estimates of increasing pressure, must have its bulk di-
minished 240 times to enable it to sink into the lower stratum, whose
density is equal to 3600 pounds to the square inch. Thus a block of
wood six inches square, would have to be reduced by successive pres-
sures to a little less than one inch square, to reach the bottom. Animal
life could not exist subject to such disorganizing pressures and survive
on being brought to the surface, subject to a corresponding inflation,
and yet we know animals do live at the bottom, and are brought, to the
surface alive. Indeed, according to this old philosophy, the shells must
be subject to the same contraction and expansion, which is hardly a
supposable case.

It is said that animal bodies, on the surface of the earth, support a
pressure of fifteen pounds to every square inch, which is equal to 30,-
000 pounds pressure for the average size of man ; and to enable him to
bear this weight (for it is not supposed that his muscular power is
equal to the task), it is contended that the pressure exists equally on
all sides, pressing with equal force upwards, downwards, sideways, in-
wards and outwards, thus confessedly making such supposed weight a
nullity. As this same pressure acts on the same principle throughout

156 AXXUAL OF SCIENTIFIC DISCOVERY.

the mass of the earth, water and air, it is necessarily a nullity every-
where, and consequently only an imaginary philosophy. The true ex-
planation is, we suggest, the existence of a molecular repulsion, as well
as admitted attraction, operating throughout the mass of all solids,
liquids, and gases, in then- normal condition, which effectually prevents
any considerable condensation from simple incumbent weight, and this
molecular repulsion and attraction may be positive and negative
electricity.

RESEARCHES ON THE FIGURE OF THE MOON.

Some interesting researches have recently been made respecting the
figure of the moon, which suggest many interesting speculations. Prof.
Hansen, the German astronomer, claims to have proved by investiga-
tion, that the hemisphere of our satellite, which alone is visible to us/
is nothing but a mountain-range, raised twenty-nine miles above the
average level of the moon's surface ; or, to express the same thing more
technically, that the centre of gravity of the moon is not her geometri-
cal centre, but twenty-nine miles on the opposite side of her geometrical
centre. That is, the more solid part of the moon would be on the i'ar
side from the earth, and all that we see of her would be a bulging
hemisphere, comparatively much less dense and weighty, projecting
twenty-nine miles beyond the surface which the moon ought to shoAV to
us if the density were equal throughout; and if the hemisphere on this
side, therefore, were uniform in weight and form with the hemisphere
on the other side, Prof. Hansen supposes, in fact, and astronomers
appear to think that he has proved his case, that the moon turns a sort
of tower of crusty, broken, porous, and therefore lighter, substance to
the earth ; so that we see only an exaggerated Alpine or Andes region,
projecting nearly thirty miles beyond the average level of the lunar
suri'ace. If this be true, there are all sorts of provoking consequences.
As we never get a glimpse of the other side of the moon, which keeps al-
ways facing about just so as to avoid showing us her other hemisphere,
we* never get a glimpse at the average level of the lunar surface.
Hence, all our conclusions as to the uninhabitability of the moon, de-
rived from a knowledge that no clouds and no atmosphere of any ap-
preciable degree exist on this side of the moon, are untrustworthy.
Twenty-nine miles above the average surface of the earth, the rarity of
even our own atmosphere would be 'probably so great as to render it
scarcely appreciable at all, even to astronomical instruments, and quite
unequal to the support of any of the vegetable or animal life of our
earth. Accordingly, conjecture may take full possession of this invisi-
ble side of the moon ; and conjecture does, in fact, give it back the
atmosphere which had been denied it, the outer margin of which is sup-
posed so far to touch the mountain heights of this barren side, as to
justify those astronomers who fancy they have seen proof of a very
thin atmosphere in the refraction of stars just on the edge of the moon ;
and to confirm the assertion of the astronomer Schroter, that he had
discovered traces of twilight there, which could, of course, only be dub
to an atmosphere of some kind. Thus much may certainly be granted,
that if Prof. Hanson is correct, the lunar atmosphere, if it exist at all,
would certainly be attracted to the opposite or heavy side, and might
well fail to be sensible at an elevation of twenty-nine miles, even though

NATURAL PHILOSOPHY. 157

quite dense enough to support terrestrial life and vegetation at the
average level of the lunar surface. It gives no proof that such an at-
mosphere exists, but does give very good reasons why, if there be one,
we have failed to detect it with any certainty.

ADDITIONAL RESEARCHES ON THE FIGURE OF THE MOON.

No one who has seen Mr. De la Rue's (London) stereoscopes of the full
moon, in which the two images are obtained separately, but by one and
the same optical instrumentality at the epochs of her extreme eastern
and western librations in longitude, according to Mr. Wheatstone's in-
genious suggestion, can fail to have been struck by the marked and un-
deniable deviation from the spherical form which the double picture
suggests, standing out, as the convex surface does, in bold and full re-
lief; exhibiting the most complete appearance of a round, projecting
(vaguely speaking), globular figure. It is quite obvious, in a certain
mode of presenting the images to the eyes, that, were it really a solid
object so presented to our view, no one would hesitate to pronounce it
rather egg-shaped than spherical. The apparent curvature of the sur-
face under such circumstances is not that of a perfect sphere, alike
throughout ; but conveys the irresistible impression of an elongation in
one direction, and that, not directly toward the eye, but forming a
pretty considerable angle, with the visual ray joining the eye and the
moon's centre. Nor does the form even present a perfect symmetry, as
of a solid of revolution ; but, on the contrary, somewhat distorted, or, as
it were, skewed. The question which now arises is, how far any such
appearances in a stereograph are to be received as evidence of a cor-
responding reality of conformation in the moon itself. And here we
must at once reject any idea of explaining them by optical distortion,
due to instrumental causes, or to photographic error, or subsequent dis-
tortion in procuring the positive impressions from the original negatives.
The instrumental means at Mr. De la Rue's command preclude the one
supposition, and the photographic process employed (collodion on glass,
optically copied), the other.

Mr. Gussew, Director of the Imperial Observatory at Wilna, with a
view to determine how far the whole or any part of this apparent
anomaly of figure is real, has subjected each of the two pictures of a pair
in his possession, given him by Mr. De la Rue, to careful and rigorous
microscopic measurement, by selecting on each of the pictures a con-
siderable number of sharply-defined, and securely identifiable points,
identical in each, and by measuring with extreme precision, by the aid
of an apparatus constructed for the purpose, their distances from the
centres and several points in the circumferences of the pictures. From
these measures (which under such circumstances must be regarded as
fully entitled to all the confidence of microinetrical measures, astro-
nomically taken at the telescope), on subjecting them to mathematical
computation, and applying the necessary corrections for parallax and
refraction as affecting the diameter of the moon, and the apparent figure
of her disk. Mr. Gussew has been led to conclude that a real eccen-
tricity of the figure actually does exist, and that, in point of fact, a por-
tion of the moon's surface having its axis directed about five degrees
from the earth as seen from the moon at the epoch of her mean libration,
may be considered as belonging to a sphere of smaller radius (and,
14

158 ANNUAL OF SCIENTIFIC DISCO VEUY.

therefore, more convex) than the mean radius of the moon by about
eighteen parts in 1,000, and, of which, the centre is situated nearer to
the earth than that of the whole moon, by seventy-three thousandths
of such mean radius (seventy-nine English miles). The portion of the
moon, then, turned toward the earth may be considered as a continu-
ous mountain mass, in the form of a meniscus lens, capping the sphere
of the moon, and rising in its middle to a height of about seventy-nine
English miles above the general level of its figure of equilibrium.

THE MATHEMATICS OF THE BEEHIVE.

In the Annals of Natural History (London), 1863, will be found an
analysis of the mathematics of the beehive, by the Rev. S. Houghton,
in which the theory of the bee's forming hexagonal cells is completely
overthrown. Lord Brougham, in his treatise Dialogues on Instinct,
remarks : " There is no bee in the world that ever made cylindrical
cells ; " and the fact of the existence of hexagonal cells in the honey-
comb is generally quoted as a wonderful example of instinctive com-
bination of means to ends in a low form of animal existence. Mr.
Houghton, however, shows that the bee makes only cylindrical cells,
and that the hexagonal and rhomboidal cells are alike the result of
pressure, and represent the angles of equilibrium between the pressure
and the resistance, just as the orbits of the planets are the midway lines
between centrifugal and centripetal forces ; the bee is not, therefore,
such a mathematician as has been generally supposed. The alleged
economy of material resulting from the bee's method of working is also
shown to be fallacious. Several mathematicians have carefully inves-
tigated the relation of expenditure of material to the mathematical re-
quirements of connected cells of given dimensions, and of a form adapt-
ed to the uses to which they are to be put. L'Hullier, in 1781, arrived
at the conclusion that the economy of wax referred to the total expen-
diture is -g^st, so that the bees can make fifty-one cells instead of-
fifty by the adoption of the rhombic dodecahedron. He also showed
that mathematicians can make cells of the same form as those of the
bees, which, instead of using only a minimum of wax, would use the
minimum minimorum, so that five cells could be made of less wax
than that which now makes only four, instead of fifty-one out of fifty.
The humble-bee, moreover, in the construction of its cells, uses propor-
tionably more than three times the amount of material that is used by
the hive-bee.

SUBSTITUTE FOR WOOD-ENGRAVING.

The London Art Journal gives the following description of a process
invented by Mr. Schulze, a German architect, for producing blocks
for type-printing, to be used as a substitute for wood-engraving. " The
material on which the drawing is to be made may be of glass or any
other hard and smooth surface. The drawing is produced with a pen,
and ink composed of pure gum-arabic dissolved in water, with the ad-
dition of sufficient sugar to prevent it cracking when dry; lamp-black,
or any other color, is mixed with the gum solution to render the work
visible. When the drawing is completed, it is covered with a coat of
bees-wax, aspbalturn, resin, and linseed oil. The thickness of the cov-
ering depends on the kind of work adopted by the artist ; if the lines

NATURAL PHILOSOPHY. 159

of the drawing are very close together, a thin coat will suffice. After
this ground has been applied, the plate or glass has to be submerged
in water for about ten or fifteen minutes ; then a strong stream of wa-
ter is poured upon it, which will remove the waxy substance above the
lines of the drawing;, but will leave that between the lines undisturbed.
In most cases, the grounding will be sufficiently high to insure a good
electrotype for printing ; but where considerable height is required be-
tween lines far apart, this can readily be effected by applying wax ac-
cording to the method now employed by stereotypists, or by adding as-
phaltum with the brush. Should the artist prefer to make his drawing
on paper, the latter must first be rendered water-proof; and after it
has undergone this process, it should be attached, with a water-proof
paste, to a hard and even plate before it is covered with the wax ; in
all other respects, it is treated in the manner just described. Before
taking the electro deposit the plate must be covered with alcoholic
varnish, and when dry, black-lead plumbago is applied with a soft
brush.

" The advantages of the process are stated by the inventor to be
The obtaining a perfect fac-simile of the artist's work ; the drawing has
not to be reversed, as in the methods now in use for copying on the
wood pictures or objects ; cheapness, and saving of time."

New Process of Engraving. The following new process has been
devised by M. Dalos, of Paris : A plate of copper is covered with a
varnish of india-rubber and zinc-white. Lines are traced through this
surface down to the metal by an ivory point. The plate is then
plunged in a solution of hydrochlorate of ammonia, the positive elec-
trode being a plate of iron in communication with the negative pole
of the pile. Iron is deposited on all the parts of the copper exposed by
the ivory point, but not on the varnish, which is removed by benzine.
The plate is once more exposed to electric action in a bath of silver,
and that metal is precipitated on the copper but not on the iron. It is
then heated to 80 C., and an alloy, fusible at that temperature, is
poured over it. The liquid moistens the silver and adheres to it, but
not to the iron, which it does not moisten. When cold, the fusible
alloy will be found standing on each side of every line, and forming a
mould, from which a new plate, adapted to printing, is obtained by a
galvanoplastic process.

DESIDERATA IX SCIENCE AND ART.

The London Society of Arts proposes annually a list of subjects for
invention, discovery, or explanation, for the attainment of which it of-
fers medals, or money premiums, varying in amount from Si 00 to $500.
From the list proposed for this year, 1864, we copy such of the sub-
jects as seem to us most important and suggestive, and as best illustra-
tive of the more practical wants of the present epoch.

Goldsmith's Work. For the best essay on ancient goldsmith's
work.

Bronzes. - - For the best essay on the manufacture and casting of
bronzes, and on bronze washes.

^Loulds for Metal Casting. For the production of a material to be
used in the formation of moulds for casting bronzes and other molten
metals, so as to enable the casts to be produced without seams.

160 ANNUAL OP SCIENTIFIC DISCOVERY.

Pigments. For an account of the various pigments used in the
Fine Arts, with suggestions for the introduction of new and improved
substances.

Substitute for Wood Blocks. For the discovery of a substitute for
the blocks used by wood-engravers, so as to supersede the necessity of
uniting several pieces of wood.

Photographs on Enamel. For the best portrait obtained photo-
graphically and burnt in in enamel.

Photographs on China. - - For the production of a dessert or other
service, in china or earthenware, ornamented by means of photog-
raphy, and burnt in from an impression obtained either directly from
the negative, or from a transfer from a metal plate obtained directly
from the photograph.

Photographs on Windows. For the production commercially of or-
namental glass for windows by means of vitrified photographs.

Fluoric Acid. - - For a substitute for fluoric acid, to be used for en-
graving on glass, which shall be free from noxious fumes.

Reproducing Designs for Printing. For a rapid means of repro-
ducing artistic designs or sketches, ibr surface-printing by machinery,
such process to provide for lowering portions of the work to fit it for
steam-printing.

Hollers for Calico-Printing. For any important improvements for
facilitating the production and economizing the cost of engraving roll-
ers for printing calicoes and other fabrics.

Aniline Colors. For a means of fixing upon cotton and other fab-
rics all the ordinary aniline colors, so that the dyed fabric will effec-
tually resist the action of soap and water, or cold dilute alkalies.

Napthaline. For a process for converting the napthaline of gas-
works into alizarine or madder-red.

Chlorophyll. For the manufacture of chlorophyll from grasses,
suitable for dyeing silk and other fabrics of a green color.

Green Dyes. For the manufacture of green dyes from coal, or
wood-tar.

Paints for Carriages. For the production of cheap purple and
yellow lakes of good quality, suitable for carriage-builders, etc., and
not liable to fade or change color.

^j

New Scarlet Dye. For the production of a scarlet dye for cotton.

Bleaching Wool. For an account of any important improvements
in the bleaching of wool.

Tltickening Colors. - - For the introduction of any substance, the use
of which will essentially economize the cost of thickening the colors and
sizes used in dyeing and dressing fabrics.

Substitute for Egg-Albumen. For a thoroughly decolorized blood-
albumen, or any economic and efficient substitute for egg-albumen in
calico-printing.

Uses of Seaweed. For the extraction from seaweed of any sub-
stance or preparation capable of extensive application as a dye, drug,
thickening, tanning agent, or any other generally useful product.
Also, for a means of rendering seaweeds generally available as a whole-
some vegetable food on board ship.

Mining Machinery. - - For improvements in the machinery for dress-
ing poor ores of tin, lead, etc.

NATUKAL PHILOSOPHY. 161

Regenerative Furnaces. For the best account of the structure and
application of regenerative furnaces to manufacturing purposes.

Melting Cast-Steel. For an easy and cheap method of melting
cast-steei in large masses.

Hydraulic Engine. For a small, simple, cheap, and effective hy-
draulic engine, which, in connection with the ordinary water service
of towns could be applied to lifts in warehouses, driving lathes, blowing
the bellowses of organs, and many other purposes where steam cannot
be made available.

Protecting Iron. For the invention of an efficient method of pro-
tecting iron from the action of air and water, applicable to the various
forms in which iron is used as a building material generally, and also
to iron ships and armor-plated vessels.

Shoal Recorder. For an instrument to indicate the depth of wa-
ter under a ship's bottom, to prevent danger when at sea or nearing
land.

Application of Electricity to Organs. For the production of an
organ in which, by the use of electricity or magnetism, tunes of greater
length and variety than those ordinarily produced in barrel-organs may
be performed mechanically.

Lace Machinery. - - For a mechanical substitute for hand-labor in
running in the outline to figures in machine-wrought lace.

Woven Garments. For the production in the loom, and introduc-
tion into commerce, of woven garments, suited for soldiers, sailors,
emigrants, operatives and others, so as to economize the cost of pro-
duction, and reduce the amount of hand-labor.

Incombustible Paper. For the production of an incombustible pa-
per, so as to render the ledgers of commercial men, bankers, etc., in-
destructible by fire.

Dyeing and Dressing Leather. For improvements in the method
of dyeing or dressing morocco or calf-leather, in such manner as to
prevent the surface from cracking in working, and to render it more
fit to receive the gilding required in ornamenting books, furniture, and
other articles.

Leather Cloth. For improvements in the manufacture of leather-
cloth, or artificial leather, especially in imparting strength and durabil-
ity, so as to fit it for the purposes of saddlers, harnessmakers, trunk-
makers, shoemakers, bookbinders and others.

New Gums. For any new substance or compound which may be
employed as a substitute for india-rubber or gutta-percha in the arts
and manufactures.

New Gums or Oils. For any new gums or oils, the produce of
Africa, calculated to be useful in the arts and manufactures, and ob-
tainable in quantity. Samples of not less than twenty-five pounds of
gum, and fifty pounds of oil, to be transmitted to the Society.

Elastic Tubing. For an elastic material for tubing, suited to the
conveyance of gas, and not liable to be affected by alterations in tem-
perature, or to be acted upon by the gas itself.

Color for Japanned Surfaces. For the preparation of any color,
applicable to the Japanned surfaces of papier madid, that shall be free
from the brightness (or glare) of the varnished colors now used, but
possess the same degree of hardness and durability.

14*

162 ANNUAL OP SCIENTIFIC DISCOVERY.

Color for Slate. For the preparation of light colors to be used in
enamelling or Japanning slate, whbh will stand the action of the heat
from the fire without blistering or discoloration, and be sufficiently
hard to resist scratches.

Electric Weaving. To the manufacturer who practically applies
electricity to the production commercially of figured fabrics in the
loom.

Japanning Zinc. For a process whereby the surface of articles
manufactured in zinc may be economically japanned.

Coating Walls. For the production of a cheap white enamel-like
composition for the interior walls, etc., of houses, applicable to all or-
dinary surfaces, easily cleansed, not liable to crumble or chip, and
capable of being tinted.

Substitute for Turpentine. For a new and efficient substitute for
turpentine, applicable to the manufacture of varnishes and to purposes
for which turpentine is now ordinarily applied.

Substitute for Pitch. For a cheap substitute for pitch, tar, &c.,
equally impervious to air and moisture, but not inflammable.

Paper Machinery. For a portable machine for planing the bars
of a rag-engine-roll true when the roll is in position.

Rollers for Printing Paper-Hangings. For a composition for feed-
ing rollers for printing paper-hangings by cylinder-machinery, similar
in consistency and texture to the gelatine rollers used in letter-press
printing, but adapted for working in water-colors.

Paper-Hangings Colored in the Pulp. For the manufacture of
papers from colored pulp, bearing upon them designs, either colored or
white, discharged after the manner of calico-printing.

Green icilhout Arsenic. --For the manufacture of a brilliant green
color, not containing arsenic, copper, or other poisonous materials.

Improved Chemical Balance. - - For the best chemical and assay
balance, suitable for the use of students and experimentalists, which
will (with 600 grains in each pan) show a difference of .005 or less.
To be sold at a moderate price.

Cheap Spectroscope. For the best and cheapest form of spectro-
scope.

Dialysing Apparatus. For the best and cheapest form of dialysing
apparatus, capable of being packed in a small compass, but of sufficient
size to aid the country practitioner in the detection of poisons and
adulterations, and in the preparation and purification of salts and drugs.

Incombustible Wick. - - For the production of an incombustible wick,
suitable for oil, spirit, and other lamps.

Cijanogen Compounds. For the economical production of cyanogen
compounds for employment in the arts, or as manures.

Oxygen Gas. - - For a more economical process of obtaining oxygen
gas than any in present use.

New Edible Hoots. For the discovery and introduction into this
country of any new edible root, useful as food for man or cattle, and
capable of expensive and improved cultivation.

Edible Seaweeds. For a means of rendering seaweeds generally
available as a wholesome vegetable food on board ship.

Colored Searches. For the production of a series of colored starches,
which can be applied to articles of dress, such as lace, etc., without in-

NATURAL PHILOSOPHY. 163

juring or staining the fabric, but at the same time give to them the re-
quired tints, and thus render them in harmony with other portions of
dress.

Titanium. For the best essay upon titanium, with suggestions for
extracting and utilizing the metal.

Smelting Zinc. For an account of the processes now in use for
smelting zinc ores, with suggestions for their improvement.

Emigrants' Dwellings. For the best essay (for the information of
emigrants proceeding to new settlements), descriptive of the means of
treating existing natural products in any locality, such as earths, shells,
chalks, and limestones, woods, barks, grasses, etc., and applying them
in the construction of dwellings. Diagrams and illustrations of the
methods of applying materials should be given.

Dutch Prizes for Investigation. The Dutch Society of Sciences have
also recently issued a prize-list of subjects for scientific investigation,
to which they invite answers to be sent in prior to January, 1865 ; and
the following are some of the topics selected : A gold medal is offered for a
paper on the Vertebrata (not including fishes) of the Indian Archipelago,
particularly those of Borneo, Celebes, and the Moluccas, and above all
those of New Guinea. In astronomy, a prize is offered for a deter-
mination, as exact as possible, of the errors of Hansen's Lunar Tables,
by the occultations of the Pleiades, observed during the last revolution
of the node of the lunar orbit. In electricity, the celebrated physicist,
Ruhmkorff, has obtained sparks of extraordinary length, by the induct-
ive machines which bear his name. Required: a determination, by
experimental and theoretical researches, of the laws which govern the
length and intensity of these sparks in machines of different sizes and
construction. Other questions are, What difference is there between
the perception of sounds with one and both ears ? Is fermentation, as
indicated by the researches of Pasteur and others, due to the develop-
ment of cryptogamia and infusoria ? and, if so, what is the exact de-
scription of these plants and animals and their mode of action ? Re-
quired : an investigation into the heat-conducting power of certain
insulating, or non-conducting substances, as glass, marble, etc. Another
is stated as follows : The researches of Gladstone and others have di-
rected the attention of physicists to the changes which the indices of
refraction of liquids undergo by a change of temperature. The Society
attach great importance to a knowledge of the relation between the in-
dex of refraction and the temperature, convinced as they are that this
knowledge would throw light on other very interesting points of the
theory of light. They therefore invite a series of exact researches on
these changes, in pure liquids and in solutions. The prizes are a gold
medal worth 150 florins, and an equal amount in money.

CHEMICAL SCIENCE.

THE RECENT PROGRESS OF ORGANIC CHEMISTRY.

The following is an abstract of an address made to the chemical
section of the British Association, 1863, by Professor Williamson, on
assuming the Chair :

One of the features of our science is the rate at which materials
have been accumulating by the labors of chemists, in the so-called or-
ganic department of the science. The study of the transformation of
organic bodies leads to the discovery of new acids, new bases, new al-
cohols, new ethers, and at a constantly increasing rate. Some of these
new substances are found to possess properties which can at once be
applied to practical manufacturing processes, such as dyeing, but the
greater number of them remain in our laboratories and museums, and
text-books. New discoveries are constantly coming in to fill up the gaps
which still disfigure our growing system. In mineral, or in organic
chemistry, there is not the same scope for discovery at present, inas-
much as the elements which belong to it do not combine in those numer-
ous proportions which occur among the chief elements of organic bodies.
But yet, mineral chemistry has not been standing still, for even the
heavy metals, most remote in their properties from those volatile and un-
stable substances of organic chemistry, have been made in many instances
to combine together, and the organic metallic bodies thus formed have
not only proved most valuable and powerful agents of decomposition,
but they have served as a connecting link between the two branches of
chemical science. A system of classification of elements is now coming
into use, in which the heavy metals arrange themselves harmoniously
with the elements of organic bodies, and in accordance with the prin-
ciples which were discovered by a study of organic compounds. It is
now many years since the attention of chemists was directed by a
French professor to some inconsistencies which had crept into -our sys-
tem of atomic weights. Gerhardt showed that the principles which
were adopted in fixing the atomic weight of elementary bodies gener-
ally required us, to adopt for oxygen, carbon, and sulphur, numbers
twice as great as those generally in use for those elements. The logic
of his arguments was unanswerable, and yet Gerhardt's conclusions
gained but few adherents. It is to be observed, that for some years
Gerhardt represented chemical reactions by so-called synoptic formulas,
which took no account of the existence of organic radicles. These
synoptic formulae represent in the simplest terms the result of a chi'ini-
cal reaction ; but they give no physical image of the progress by which
the reaction is brought about. The introduction, in this country, of the

164

CHEMICAL SCIENCE. 165

water-type in connection with poly-atomic as -well as mon-atomic radi-
cles, -was found to satisfy the requirements of the synoptic formulae.
Gerhardt was the first to adopt them from us. He gaye a system of
organic chemistry on that plan, and his book has been of immense ser-
vice to the deyelopmeut of our science. The extension of these prin-
ciples to mineral chemistry had been commenced in the cases of the
commonest acids and bases, but their general introduction met with
difficulties, and sometimes seemed wanting to their complete success.
It was reserved for Prof. Cannizzaro, of the University of Palermo, to
show us how the remainder of the knot could be untied. He argued,
upon physical as well as chemical grounds, that the atomic weight of
many metals ought to be doubled, as well as those of oxygen, sulphur,
and carbon. His conclusions are confirmed by the constitution of those
organo-metallic bodies which I mentioned just now, and it certainly
does seem to supply what was still wanting for the extension of our
system of classification from the non-metallic elements to the heavy
metals themselves. The elements are now arranged into two principal
groups : 1 . Those of which each atom combines with an uneven num-
ber of atoms of chlorine or hydrogen. 2. Those of which each atom
combines with an even number of atoms of chlorine or hydrogen.
Like every classification founded upon nature this one draws no abso-
lute line, as some elements belong to both classes. The first group in-
cludes the mon-atomic elements of the chlorine family, the tri-atomic
elements of the nitrogen family, hydrogen, and the alkali metals, silver
and gold, - - in all about eighteen elements. The usual atomic weights
of these are retained. The usual atomic weights of all the other ele-
ments, biatomic. tetratomic, etc., are doubled. This second group in-
cludes the oxygen family, carbon, silicon, and the alkaline earths, the
metals zinc, iron, copper, lead, etc. Every step in our theoretical de-
velopment of chemistry has served to consolidate and extend the atomic
theory, but it is interesting to observe that the retention of that theory
has involved the necessity of depriving it of the absolute character which
it at first possessed. Organic compounds were long ago discovered,
containing atoms of carbon, hydrogen, and oxygen in proportions far
from simple ; and the atomic theory must have been abandoned, but for
the discovery that the atomic, or rather molecular, weights of these
compounds correspond invariably to entire numbers of the elementary
atoms. We now use the term " molecule " for those groups which hold
together during a variety of transformations, but which can be resolved
into simpler constituents ; whilst we