New-York tribune., 1874-07-06

do
- - v. .ho hlock oxide Of manganese Ii should |
seeao " ;rt;mately mixed with the chlorate. There
~ od 20 he greater speed attained IN the operation
while the danger OF an explosion becomes less
Tr,,prRING STEEI--It is not generally known |
that steel cen be made so hard that 1t Will pierce
any substance but diamond. Many jewelers. ana
lapidares experience great difficulty In getting the
points of their drills hard enough to pierce an anne
thyst. For their benefit, as we'll as for tnat Vi
miners aud others using drills requiring very haru
point the following method of treatment is recon.
mended The drills should be- held, II small oy n3i n3i
pincers or tongs while heating, The tool shoul39
frst be heated 10 white heat; anu tLeL pond
and then removed and inserted into the wax III aliI
other place. This operation should oe IePeate" ""
tho instrument is too cool to enter the wax
DANGER-NoTICE TO LOCOMOTIVE ENGlNLLhS'-
According TO Gen. Norm. method has been III sue
eessful operation for year on the line OF the Noit
ern Company of France for informing the driver OF
atrain whether the way is open or not According
70 this arrangement the sigualman, when he turns
the disc sends an electric current in the direction OF
the coming train 10 a bar placed between the rails;
when the engine reaches the spot meth DIllsh,
placed between the wheels, sweeps me cross-oa
the current passes to the engine, and, by means OF
IN electro magnet presses upon lever when opens
the steam whistle, thus making 1t virtually auto
matte.
DESTROYING MAY-BUGs.-A French writer gives
the following method of destroying the May-bug OF
coekchafer on large scale, his captures amounting
to ten or fifteen gallons in night For this purpose
he smears with tar the inner surface Of an old
barrel one head of which has been removed; and at
twilight he places near the bottom of the barrel
lighted lantern. Insects of all kinds are attracted
by the hight and in flying around II they strike
against the sides of the barrel, when tneu MMihss
are gummed and they fall TO the bottom lntse
NAV then be thrown into boiling water or otherwise
DESTROYED and they can, indeed. be made 10 serve
useful purpose manure. If similar metnoI OF
destroying the moth OF the cankeT-WoTn, Wnlch i
SO fatal 10 the apple crop in ew-England, can De
successfully applied il will prove much more Simple
rs well as more effectual than any remedy mtherIo
employed.
METHOD OF CoIORING VENEERs-A method of
preparing veneers in which the color saturates the
entire mass, and of course is exhibited even when
the surface is abraded consists in first soaking them
for twentyfour hours in solution of caustic soda,
md then boiling them in it for half an hour. They
are then washed with water until all the aka isre-
moved. when they are ready to receive the dye
This treatment with soda effects general disinteg-
ration of the wood that when moist 1t is elastic
and leatherlke and is prepared to absorb the color
Veneers thus treated if left for twentyfOur hours
IN hot decoction of logwood and after superhclal
Tyeing immersed for twenty four hours in hot so
LUTON of copperas, become OF beautiful and per
ane9t black @ a sUuTn mons al Te
low color, not in the least affected by subsequent
vanishing. Coralline, dissolved in hot water, to
which little caustc soda and one-ffth its volume
pf soluble glass have been added produces rose color
of different shades, dependent ON the amount OF
coralline taken. After dyeing they are dried be-
tween sheets Of paper and subjected to pressure TO
retain their shape.
Is HYDROGEN METAL f-The discussion concern
ing the presumable metallic nature of hydrogen.
which is periodically renewed, has received fresh
impulse from some discoveries recently made by
NJ. M. Troost and Hautefeuille, who announce that
hydrogen forms O definite chemical compound with
two equivalents OF either sodium potassium.
Potassium, when heated to 200o, will combine with
hydrogen but at 9O0o the compound Is entirely de-,
stroyed. The newly discovered compounds present
all the characteristics Of amalgams-the metallic
luster and physical appearance of metal The
authors therefore urge that these bybrides Of So
dium and potassium are true alloys, and consider
their existence as new proof that hydrogen Is a
metal. Another discovery of similar tenor by the
same investigators is the fact that palladium forms
with hydrogen a definite compound with the formula
gen gas like platinum and in variable quantity, ac
cording to its physical condition This property of
fhe palladium alloy, according to the authors. ex-
plans the want of uniformity of the numerical re-
suits obtained by Graham, the originator of this his
method of inquiry, according as he employed the
palladium as wire or in the form Of sponge.
C1roRAr AZ A PREsERvATTvE-T1e PHILADELPHIA
Medical Times contains an article by DR.. W. W. Keen
upon the anatomical, pathological and surgical uses
of chlOral, in which he recommends this substance
very strongly for the preservation of objects of COM
paratve anatomy and natural history. 1t is used by
injection into the blood vessels By immersion, and
In his opinion ii is likely to supersede many of the
preparations now in use Its special advantage is
that the color of the objects is preserved perfectly
and all the parts have natural consistency, while
there is nothing either poisonous or corrosive to
affect the general health of the experimenter to
injure instruments.
For preserving human subject for dissection,
half pound of chlOral will suffice, at a cost of a
dollar or less. solution for preserving specimens
of natural history of ten or twelve grains to the
Of water Is quite sufficient, is much cheaper
than alcohol, and the bottles instead of being her
metfcay sealed are closed by glass shoppers.
ordinary cOrks. Dr. Keen has thus kept pUs from
various substances and diseased gTOwths of various
kinds Of other specimens for months and found no
change whatever in their character. ChlOral is
tremely antagOnistc TO fungi and infusoria q very
weak solution of il killing them instantly. The
deOdoTiZng well the antiseptic properties are
equal, in Dr. Keens opinion, TO those OF any sub
stance now known.
EXPLOSION AND IGNITION BY PERMANGANATE OF
PoTAsH AND SUIPHURIC ACID.-AccOrding to a Sc
ries Of experiments by B0ttger. mixture of parts
of perfectly dry permanganate of potash, with
about TO parts by weight of concentrated sui
phuric acid will frequently cause most violent
plosiOns WITH and subsequent ignition of many sub
stances especially volatile oils contact with
chem at ordinary temperatures as by placing 10 to
~ drops of such an oil in a capsule and stirring into
1t as much of the mixture will adhere to the end
of a heavy glass rod. Such explosions occur with
oil Of thyme of mace of cinnamon, of rue of cubeb
of lemon of maroram, and of spike and with recti-
6ed oil of turpentine Simple ignition without ex-
plosion, occurs with oil of rosemary of lavender of