The Cincinnati daily star. [volume] ([Cincinnati, Ohio]) 1875-1880, 1878-03-07
SCIENTIFIC.

of pure copper, IL zinc or tin, 6 magnesla,
! 3.6 sal ammoniac, I.6 burn limestone and 9
cream Of tartar. The copper is iirstmeIt6d,
then the nagnesia, sal alnmoniac, lime
stone and cream of tartar in powder are
gradually addt3 -rrayateIy. The whole is
kept stirred TO. II an hour, the zinc or
tin being dropped III piece by piece, the
stirring being kept up till they melt. Last
of all the crucible is covered and the mass
kept in fusion for thirty.fve minutes.
The scum being removed the metal is
poured into moulds. The alloy is fine
grained, malleable and takes high polish.
1t does not easily oxidize.
TURKISH "RUsmA As is well known
the famous Turkish ''rusma, or depiatory,
owes it's action on the hair to the persul-
phide of lime it contains, the arsenic pres
ent being only the bearer of the sulphur,
and, in this connection, the following ra-
tonale of the process resorted to by tam
ners with gas lime, as given in the Polyteh-
nische Central Halle, will be interesting to
many: The depilatory action depends ex-
clusively upon the persulphide of lime, and
is heightened by the presence Of cyanide of
calcium. Pieces of hairy skin, brought in
to mixture of these two compounds, are
at once deprived of the hair, the destruc-
ton commencing on the ends and stopping
at the root without acting in the least
upon the skin. 1t appears that in this
contact, one atom of sui phur combines
with the substance Of the hair-destroyin
it-and as the same time leaving an insolu-
BILE sulphate of lime, which is pre-
cipitated together with the decomposed
hair.
STAG FRoM IRON SuRrAcEs.--It is now
proposed to manufacture glass by using
the Stag from iron surfaces, in its liquid
state, direct from the blast furnaces. Ac-
cording to this method, which has just
been undertaken in England, the Stag is
conducted while in q liquid state into q
tank holding fifteen cwt., where it is mixed
with other materials, and, in an Incredibly
short space of time, as compared with the
ordinary mode, glass is produced. This
glass is represented to be of an exceedingly
soft or plastic nature; it is perfectly acid
proof, and capable of use for all purposes
for which the best bottle glass is suitable,
it also cuts readily with the diamond, and
is available as rough plate for rootings,
skylights, greenhouses, roofing tiles, and
for many other uses from which glass, as
heretofore manufactured is, on account of
its cost. necessarily shut out. Specimens
have. also been produced of this glass
colored brilliantly, and adapted to the
various applications to which colored glass
is devoted, with the important advantage,
in the new article of cheapened cost.
BLACK PAINTs.-Black paints, says a
French journal, from the residual products
of COL and shale oil manufacture, and
oxide of iron paints, are peculiarly suitable
for the various descriptions of iron work.
In regard to the different oils in use, lin
seed is by far the most valuable; and it not
only improves greatly by age, but ought tc
be kept at least six months after it has
been expressed before being used; it may
be used as dryer by simply boiling it, Oh
by adding certain foreign substances. Nut
oil and poppy oil are far inferior in
strength, tenacity, and drying qualities tc
linseed oil, and are used to adulterate the
latter. Employed in proper manner
no better protection can be found for iror
structures than oxide of iron paints. The
real value of any plant depends, in word
entirely upon the quality of the oil, the
quality and manufacture of the pigment
and the care bestowed upon its production
Or composition; these points being of rea
consequence, rather than any unknown
process or material employed in the pre-
paration.
TIE DECAY OF BUILDING STONES. s.-One Of
the most practicable methods of preventing
the decay of building stones caused by at
mospheric influences, is found to be the
saturation of the absorbent surface with a
diluted solution of soluble silicate of soda,
and then treating it with a solution Of
chloride of calcium. By the mutual ac-
ton Of these solutions, a double decompo
sition is induced, the silcic acid parting
with its soda to the chlorine, producing
chloride of sodium, or common salt, and
combining with the lime to form silicate of
lime; the salt being washed away, only
the silicate of lime remains. The slicate
of lime. thus thrown down, is salt which
is not only in itself non-absorbent, and sin
gularly powerful in resisting the action OF
ordinary atmospheric influences, but has
the property of adhering readily to the
surface of the minute particles of which
stone is formed. The stone haying its par
ticles thus coated with slicate of lime, and
all the absorbent surface being thus pro-
tected, the result is an immediate and
great hardening of the stone, so far within
its substance as the solutions have been eb-