A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...

152 THE METALLURGY OF ANTIMONY.
mony is isolated, while the potassium forms an amalgam with the
mercury. An explosive alloy can be made by calcining for three
hours a mixture of 100 parts of tartar emetic, 3 parts of lamp-black ;
or 100 parts of metallic antimony, 75 parts of roasted cream of tartar,
and 12 parts of lamp-black. The crucible used for this purpose must
be coated with a thin layer of carbon to prevent adhesion. This alloy
may be used in the manufacture of matches that are damp-proof.
Cooke's Alloys.—Two crystallised compounds of antimony and zinc
are known, with Sb2Zn3 and Sb2Zn2 as formulae. The former is prepared
by melting together 57 parts of antimony and 43 parts of zinc.
After carefully stirring the mixture, it is allowed to cool in the crucible
until a crust is formed on the surface, which is then pierced and the
liquid portion poured off. The interior of the crucible is then seen
to be covered with magnificent prismatic crystals, terminating in
points.
The latter, Sb2Zn2, is prepared in the same manner with 68*5 parts
of antimony and 31*5 parts of zinc (Fremy). These two alloys
possess the property of decomposing water at 100° C.; thus, 200 grms.
of Sb2Zn3 can set free 130 c.c. of hydrogen gas in ten minutes. This
decomposition can be accelerated by adding a few drops of chloride
of platinum : 200 grms. of Sb2Zn2 can then set free 244 c.c. of hydrogen
gas in ten minutes. Cooke has recommended the use of these
two alloys for the production of pure hydrogen in the laboratory.
Reaumur's Alloys.—When a mixture of 70 parts of antimony and
30 parts of iron is heated to a white heat in a crucible, the resulting
alloy is very hard, white in colour, and slightly magnetic, the nardness
being increased in proportion as the quantity of iron is increased.
It is always formed when iron is used to excess in reducing antimony
sulphide.
Alloys of Antimony and Gold.—Antimony has such great affinity
for gold that a very minute quantity of antimony vapour will modify
its ductility. The alloys are straw-yellow, the fracture being grainy
and dull, like that of porcelain. They are used in jewelry.
Alloys of Antimony and Copper.—Equal parts of the two metals
form an alloy having a beautiful violet colour.* In combination with
tin, the alloy is used in industries.
Alloys of Antimony and Silver.—They are white and brittle.
Alloys of Antimony and Aluminium.—These alloys, discovered
recently, have been, studied by M. Pe"cheux. Yon Aubel (1895)
obtained the alloy SbAl, which melts at 1080°; L. Guillet (1902)
obtained the alloys SbAl, SbAl3, SbAl4, and SbAl10, which turn to a
* It is known as " reguhis of Venus."