New-York tribune., 1875-07-12
APPLIED SCIENCE.

taken as basis tho years 1898 10 lo'I anu nao "'"
studied the distribution Of storms from the year
Y7S5 10 1872 With respect to this latter subject ne
Hnds that on the 10th, l4th, and 18th days OF tne
lunar month storms are particularly Prevaent, anu
on the 9th, Goth, and oath days they are least prey
elent In general, the evidence points to the con
elusion that no lunar influence is plainly percepu
bic.
ADVANTAGEOUS CONSTRUCTION THE SPECTRE
sCoPP-In some remarks upon the optics OF the
epcctroecope Mr. Sorby states that in the construe
ton of spectroscope the eyepiece should DC OF az
long focus possible as to cause all the rays 10
enter the eye. All magnifying beyond this means
loss of brlianey; and If the spectrum appears IN
snflicently large an increase in the size OF the col
limating and telescope lenses, together with tne
prisns; an increase in the number OF Prlsihss s
ehould be made, until the spectrum appears SUI
6cently large 10 suit the requirements OF the oo-
server.
RELATIONS BETWEEN CHEMISTRY AND TIER
MorIcs.-Tne study Of the evolution OF heat In
chemical combinations is new branch OF science
belonging partly to physics and partly to chemistry
and the number of facts already observed is sur
ficiently numerous to indicate certain laws which
are set forth by BertheOt. He premises that IN the
art of producing any chemical change the molecules
hit sharply against one another, and give on neat,
lust as when hammer strikes bar of iron From the
strdy Of the relations between the amount OF neat
an the amount of work done il possible to estab-
hsh some theOrelns OF thermo-chemistry.
gisis have long desired to obtain an instrument
whereby comparable observations of the amount OF
solar radiation can be made. Various experiments
on this point have been made by the Rev. Mr.. STOW
and others; and Mr. Symons has shown that this OBJ
iect is attained by the Of a mercarial maximum
thermometer of which the bulb and one inch OF the
stem are coated black; the whole being near the
% or sSSDd the oa air has BEEN Exhausted To ali
such thermometers the title of vacuum Thermometer
has been applied It is, however, found tiat tne
amount of exhaustion varies considerably In lnstru-
snents of different makers and that the indications
of the thermometer are thereby greatly affected
THE Gas Gun FOR FOG SIGNALs.-A very lnee-
nious application has been made by Mr. Wigham OF
the explosive nature of mixture of ordinary gas in
air. He establishes, at any point the coast where
q fog signal is desired, a gas gun. 1t Is simply
tube Of iron connected with the gas-holder by the
proper pipe; the latter of course may be at any con-
venient distance. The gas-holder is filled with a
mixture of one-fourth air, and the remainder coal
gas and oxygen, and this mixture is allowed TO How
into the gas gum when it may be fired off by touch.
ing match to the proper orffce, taking care, OF
course. to close all communication with the holder.
BY using electric spark instead OF the match the
service of the gun may be made still easier. lhc
flash from this gun is said to illuminate the fog
much better than that from discharge OF gun
powder
IMPROVED CLOCK WORK GOvERNoR.-In order to
secure perfectly regular motion in the clock work
applied to revolving lights in lighthouses, Dr. Hop
kinson the scientific adviser OF the glass-works OF
Messrs Chance & CO., near Birming gham states that
he has introduced simple centrifugal governor.
The governor balls have to lift heavy weight
which is in the form of a ly-wheel and the circum-
ference of which, on being raised slightly, presses
against certain fixed pads the friction of which soon
dimnishes the velocity of rotation Of the y-wheel
and the governors sufficiently to allow these latter
to fall back to their original position lie calculates
that work to the extent of 500 pounds per minute
must be done on the governor in order TO accelerate
the clock one second per hour. This form OF gov
ernor possesses the advantage that it checks any
ceicraton of the clock more promptly than when
friction rubbers carried by the governor balls
and IT il also easy 10 ADJUST.
- = -~-~EEss'~s
ED1lrNp's THEORY OF fffE NATURE OF ELEC-
rRICIrY-In report ON the theory lately advanced
by Prof Edund as to the nature of electricity, Dr.
Emsmann states that apparently Edlund has, in this
matter taken such q step forward as was made
when previous investigators able. by means OF
one ather to explain both optical and thermal phe-
nomena Edlund's theory consists essentially IN
ascribing to the ather itself inertia which re-
Guires slight interval of time In order to affect It's
movement. The flow of ather from one body to
another explains the electro-dynamic phenomena.
while its abundance deficiency in any body serves
TO explain the electro-statc phenomena. As regards
the chemical influence of the galvanc current it is
deemed that the electricity has an equal lnhuehce
upOn the bodies that to be separated or COM
bined by it, The rotation of the plane of polar
ization of light is elucidated by the simple asSunp-
tion that the electric 9ther Is not dherent IRON the
optical ather and i'll general 1t IS to be acknowledged
that Edlunds theory Is based upon well-knoWn
facts and is distinguished by its simplicity and suf-
fciency.
THE PHYSIOLOGICAL ACTION OF LIGHT.-In
memoir on the physiological action of light. by
Profs Dewar and McKendrck, these authors have
especially directed their attention to the effect pro-
duced on the retina and optic nerve. Their inquiry
divided itself into two parts, first TO ascertain the
electro-motive force of the retina and the nerve;
and, second TO observe whether this was altered in
amount by the action of light. They conclude that
The action of light is such to alter the amount OF
the eecromotive force to the extent of from three
TO seven per cent of the total amount so that
strong fash of light lasting the fraction OF asecond
produces a marked effect. lamp held at distance
uf four five feet, and equally, the light OF small
gas flame, after passing through depth OF twelVe
inches of a solution of salts of copper and, potash,
also produce sensible effects When dif1hse light
Is allowed to fall on the eye OF frog alter the latter
natural eectrO-mOtive power H IN tne nst place IN
creased then diminished. The effects In question
are caused BY those rays Of light that appear to be
the least luminous; namely, the yellow and the
green.
/; PREPARATION OF EBoNITE.- The use of ebonite
pne of the newer preparations of India rubber,
is constantly increasing, account OF its
better applicability TO many purposes IN the
arts than it's near ally vulcanite. The two substan-
ces are quite similar being composed Of India rubber
and sulphur with some preparation of gutta percha
shellac asphalt, graphite, etc. although these
latter are not essential In vulcanite the amount Of
sulphur does not exceed 20 TO 80 per cent whereas
in eboDite the percentage Of sulphur may reach as
high as CO. Anincreased temperature Is also required