New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1873-03-29

generally known ss French chalk. used by talors
for making marks upon cloth, is manufactured by
rubbing ultramarine, oohre, &c. recording to the
color desred) with ppe-clay softened with water.
The mixture is then poured into molds and dried in
a slightly heated roOm
LEATHER GLUE.-A substance known as Leather
glue is prepared by mixing ten parts of sulpbde of
carbon with one of oil of turpentine, and adding
enough gutta-perchs TO thicken the mass. The
leather surfaces to be united must be freed from OIL
which is accomplished by subjecting them TO
pressure by laying the leather upon botting paper
and applying hot iron. After tracking together the
edges TO be joined with the cement, they are to dc
kept under pressure until the glue is entirely dry
IMPROVED ELASTIC BANDs.-The ordinary elias
tic bands, with rubber threads woven INTO then'
lose their elasticity in a short time by ae-
ton of the atmospheric but bands free from
this defect, and at tie same time more elegant and
stronger, are made at no greater cost by causing
twostps of CLOTH previously coated on the inner sur
faces with solution of indiarubber IN benzne ana
with band of stretched rubber threads OF RUBBER
band inserted between them to pass through rollers
compacting the three by this pressure into lIln
fabric.
IMPROVEMENT OF RANCID Misunderstanding 10
Land and Water rancid butter can be greatly I'M
proved IN quality by washing it thoroughly IN
lime wafer and then clearing out the lime water by
good washing in cold spring water. The lime
water is easily made by allowing lump of lime the
size Of the fist to slake in bucket of water, stirring
il well, and afterward allowing the lime to settle.
1t is said that q large business is now done III En-
gland by sundry persons. who purchase rancid
butter at low rates aud sell it again at much higher
prices, after manipulating it in the manner men
toned.
NEW PROCESS FOR PRESERVING MEAT-Accord-
ing to The London AheRGum, Mr. Marietta has lately
been calling attention to process for preserv-
ing meat fresh. This consists in dipping the fresh
meat into melted butter and then packing it in salt
The examination of the specimens furnished by him
is said TO have been quite satisfactory; but in the
opinion of The AheA6Hm. it does not differ essen
tally from that of dipping the meat in paraffine,
which answered for temperate climate, but failed
in tropical region.
SURFACE HARDENING OF CAsT-IRoN.-The wearing
of casiron surfaces exposed to sliding friction
be almost wholly prevented by tempering the surface
with mixture of 81 ITO pnts Of water, 800 pounds
of sulphuric acid and 1908 grains of nitric acid. The
article should be heated to a cherTy-red, and pro-
tected from the oxidzng effect of currents of air by
sheet-irOn box The process is especially adapted
10 the hardening of bearings of axles which, while
when regularly fabricated. last as long, even when
there is great rapdity of motion.
IMPROVED TRACING PAPER-Puscher of Nurem-
burg has lately suggested solution of castor oil in
absolute alcohol for the purpose of manufacturing
tracing paper. The oil is 10 be diluted with one
two or three times its bulk of alcohol according to
the thickness of and the amount consequent
y required for rendering il transparent This be
laid oob nv mas NJ n md
minutes after the application the paper will be dry
transparent and ready for use. 1t will readily re-
Ceve the mark Of pencil or India ink and as by
immersion III absolute alcohol the oil can be re
moved the paper can be restored to its original
dihon, if desired.
SIDERIN-YELLow. AND WATER-GIAss. &C.-The
addition of hot, saturated solution of bichromate
of potash TO neutral solution of sesquichlorde of
iron produces, after heating for some time fine
yellow precpitate of basic chromate of sesqui-
oxide Of iron of definite constitution which, when
washed and dried, may be used under the name of
siderin-yellOw pigment, free from lead and unaf
fected by light and the atmosphere This is not
only suitable for an aquarele and rapidly drying
oil color, but, when intimately ground with water
glass it forms a coating that dries rapidly and
hardens like cement into stony incrustation which
running water does not affect With ultramarine it
gives green pigment of similar properties The
following proportions are based upon the chemical
reactions which take place in the preparation:
Crystallized sesquchlOride of iron, 433 parts, and
bchromate of potash ,473 parts. After long boil
ing of these constituents together in water SIS parts
of the basic chrOmate of the sesqui-OXide OF rOn
sidern yellow, separate, while 30 parts of water Of
crystazation are liberated from the sesqui-chorde
of ron and 1O49 parts of chrOmo-chloride of potas
stun remain in the aqueous solution with 3S9 parts
of chromate of potash.
MoLps FOR ELECTRoTYPEs.-The employment Of
graphite with gypsum and gutta percha molds for
electrotype purposes causes much trouble and loss
of time because the graphite must be rubbed till it
assumes metallic lusteT which, though matter OF
10 great difficulty with smooth, even surfaces, very
troublesome when irregularities occur. Better re-
suits are obtained when the gypsum mold soaked in
wax is thicky covered over with mixture of silver
nitrate solution supersaturated with ammonia and
alcohol and then exposed to the action of sui
pburetted hydrogen whereby sulphide of silver is
formed which is a good conductor. The free am
monia in the solution causes it to adhere read
lily to the wax. leaving, on drying uniform,
unbroken covering of the silver compound.
When a somewhat powerful battery of four
or five Daniels elements is used the layer Of copper
quickly diffuses itself over the whole surface
whereas, by employing feebler current, softer and
less friable copper IS obtained
good method Of preparing the solution is as fol-
lows: dissolve IS grains of lunar caustic in 30
of water, to which 49 grains of ammonia of sp. gr
O9O to be added. and then IS grains Of absolute
alcohol
DIFFERENCE BETWEEN CoLUMBE AND GALIISE.
Mr.. Tegetmeier calls attention to the very great