The citizen. (Frederick City, Md.) 1895-1923, 1897-11-19

tiVAJP pc arc OpNdlhCu ny OCluud
electrician. Herr Josef Rieder, by a
simple electrical process. Plaster of
Paris is poured over the OBJECT, forming
a short column, which is detached and
fitted with an ebonite sleeve, leaving
the top and bottom alone exposed.
The cast is placed face upward in a
vessel containing an electrolyte. The
piece of steel to be etched is laid on
the face of the cast-which projects
above the surface of the liquid-and
made the anode of the cell, the cathode
being wire spiral placed in the liquid
A moderate current of considerable
voltage suffices. The current passes
through the high psrts of the cast, dis
solving the steel and allowing it to set
tie until a complete copy of the orig
inal surface is obtained. Difficulties
are the softness of the plaster aud ac-
emulation of carbon from the dis
solved steel.
The liquefaction of iuorine, first an
nounced last May, is an achievement
of great interest on account of the in
tense activity of this element. Fur
Their study by Profs. Dewar and Nor
issan have shown that the gas is easily
lquefied at the temperature of boiling
arr, that the boiling point of liquid flu
orine is 1S7 degrees below zero Cent?
grade, that it does not solidify at 30
degrees below, and that its density
Is LA. 1t is soluble in LIQUID oxygen
and liquid air. AT the lowest temper
AZURE reached, it had no action on dry
OXYGEN, water or mercury, hut com
bined violently with hydrogen and oil
OF turpentlne. A remarkable eXplo-
slve substance produced with most OK
ygen seems to he hydrate of fiuorine.
A lady inventors lifeboat, which
has been approved by the British Adj
mlralty, carries three long cylinders,
into which million cubic feet of air
can be compressed. This air will drive
the boat Is miles an hour for six hours.
A curiosity Of the Stockholm Exhi-
bition is pine tree section feet in di-
ameter from 90 to 20 miles north of the
Arctic Circle.
After long experiment, Mr.. H. N.
Warren, prlncipaFof the Liverpool Re-
search Laboratory, has announced Il
new electrical generator, which PROM
ises liberal and inexpensive supply
OF current for many purposes, and
seems to he the nearest approach To "a
perpetual motion apparatus yet attain
ed III practice. The positive element
is composed Of plates of porous COM
pressed graphite, one quarter of each
plate being made active by immersion
IN platlnic oxolate aud subs quent igni.
ton in an atmosphere of hydrogen.
TINS operation gives very finely di-
vlded platinum surface. TO construct
the cell, several of these prepared car
Don plates are attached to a circular
lead beam which surrounds porous
diaphragm containing as negative ell
enent rod of amalgamated zinc, the
calbons being arranged with their
platinlzed portion projecting above the
solution of strongly acidified ferric sui
phate. On completing the circuit, a
powerful current is set free, which con-
tinues until the oxidation of the zinc
reduces the ferric sulphate to the state
OF fer, Gus sulphate. The zine is then
Withdrawn, when the active platinum
surface condenses atmospheric OK
ygen, and which reoxidizes the
ferrous salt, and thereby re-
news the action when required
Four ounces OF ferrIc salt in a
generator 7 10y inches in size gives "A
very steady current of 2 volts and 8
amperes for "a hours
Many medical men now contend
that the artificial production of fever
is powerful means of combating acute
Infectious diseases. In support of the
view two Canadian physicians report a
series OF experiments on rabbits, high
temperature having been first induced
10y injury to ganglionic cells at the base
OF the brain, when the animals were
inoculated with the minimum fatal
dose OF hog cholera and diphtheria,
The animals with the artificial fever
lived longer than others, some even
surviving the infection.
1t is predicted that novel motor
carriage now being built by two
French inventors-Capt. Draulette and
NJ. Catois-will be one Of the greatest
automobile curiosities of 1898. 1t COM
prises two wheels five feet in diameter.
mounted on a common axle, with the
body between. The motor. electric, pc
troleum or steam-revolves at high
rate of speed round a vertical axis, and
by its gyroscopical action tends TO keen
the seat horizontal and the rider m
right.
A curious device for propeling boats
automatically against the waves il the
fin motor Of H. Linder, of Naples.
which has given to the little wooden
boats of "a Berlin maker the
name OF 'autonauts." The motor i'm
itates the tail-fins OF dolpnins. etc
Each FIN consists of steel bar. from
which Hat blades, tapering in thick
ness, project backward like the teeth
OF comb; and each end of the boat is
fitted with one Of these fins, placed
horizontally so as to rest on the surface
OF the water at right angles 10 the keel
The waves bend the steel blades.
which, reacting, press the water back
ward and thus move the boat forward
against the waves. The fins have been
successfully tried on hoats up to Is
feet III length, q boat IA feet long hay-
ing been found to require total active
fin surface Of 10 square feet, and speed
OF about thres miles an hour has been
obtained in sea stirred up by strong
wind. The one use thus far found for