Daily inter mountain. [volume] (Butte, Mont.) 1881-1901, 1899-06-24
SCIENCE.

Even window washing is now a subject
OF scientific study. For five years a Ger
man chemist has been investigating the
faction of pure water and dilute acids
upon plate glass, and he has prepared
tables showing exactly how much of the
glass is dissolved by each reagent. From,
these n other results. Mr.. w. L Scoville
concludes that windows should be cleaned
win weak ammonia water and polished
with dilute hydrochloric acid and friction.
The ammonia, though sufficiently solvent
10 suspend some Of the silica and streak
the glass. has less effect than soda or
potash; and the acid neutralizes the am
monia and the alkali in the glass. forming
some soluble chlorides that aid in the
polishing. The final operation is Trying
and polishing with a clean cloth. To
avoid damage to paint and yarnish. not
more than half an ounce of concentrated
ammonia water should be used in a pail
ful OF water; and the usual two or three
ounces of strong acid to the pailful
should be lessened if the window frames
are of metal.
Though the fluorescent screen is very
falntly luminous. Rev. Alexander Motfet
f1nds If the ROentgen rays were con-
tinuous instead of intermittent they
would exert an effect 500 times greater
thah sunlight falling perpendicularly
~IS " oIly 7 Per cent OIL the
energy lmpinging upon the screen is rep
resented by the visible rad.ations. while
the interval between two X-rays dis
charges is about 1000 times the period
covered by the discharge itself. A
Georgia inventor. it may be noted. has
produced a Ro%entgen-ray lamp. which is
claimed to yield an intense light from the
oombardmen Of a covered magnet core
by the cathode rays.
Inc reducing property of cathode rays
has been shown by NJ. Wizard to be due
TO hydrogen, the conclusion being reach
ed, moreover, that the rays from the
cathode are formed entirely by hydrogen.
This suggests the novel plan of restoring
exhausted vacuum tubes by passing gas
through a heated platinum plate in the
tube wall-such diffusion having been
shown by Deville to take place rapidly.
FROM a description Of the torpedo con-
trolling devices of Walter Jameson and
John Irotter. 1t appears that a very sat
isfactory arrangement for steering nv
Hertz waves is obtained by means of
two solenoids. or wire SpiralS, the right
or left OHa--accOrding To the direction of
the current received-being made to act
as a magnet. drawing in ar iron core, and
giving a corresponding turn to the rudder
attached. The waves are sent out from
the controlling ship by manipulating the
switch of al induction coil. They are
received by two rods projecting from the
torpedo above the water, pass to a coherer
OF special type, n by lessening the re-
slstance of the metal power of this CO.
hercr close the secondary circuit of a re.
lay, causing an electric current to flow
through a solicitor to the proper sole
mold, which sucks in its core and keeps
the helm turned until the desired course
is attained, when the operator opens the
induction coil switch, and the wave
cease. The helm then flies back to the
midship position.
The production of photographs in relief
IS the promising nt~. art of NJ. Lemac,
who has used his process for fine medal
lions from living persons. Two success
slNe film negatives are made, the model
being in exactly the same position, with
the light--from a concentrated source like
a magnesium cartridge--applied to OPP
pOsitc sides. thus bringing out in intense
black the most salient points of the face.
A print is made from the two negatives
exactly s%uperposed. The print is re-
touched to bring out hair and drapery,
and any lettering desired is drawn with
India ink If to be in relief or Chinese
white if to be depressed. the outline of
plaque or medallion being traced w it'll
India ink. From this proof is reproduced
a negative Of the desired size. Low re-
liefs are produced from proofs on bich-
romated gelatin by simply washing out