gives the sulphur reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Pyargyrite

Formula. [,Ag]^{3}[,,,Sb].

Behavior
(1) in glass-bulb. Sometimes decrepitates, fuses readily, and,
when strongly heated, gives a red sublimate
of SbS^{3}.

(2) in open tube. As in the preceding.

(3) on charcoal. Fuses with much spirting and covers the
charcoal with antimonial fumes. When the
residual AgS is heated for some time in the
oxidizing flame, a bead of pure silver is
obtained.

(4) in forceps. --

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. As the preceding.

(8) Special reactions. --

* * * * *

Mineral. Proustite

Formula. [,Ag]^{3}[,,,As].

Behavior

(1) in glass-bulb. Fuses and at a low red heat affords a small
sublimate of AsS^{3}.

(2) in open tube. Gradually heated it gives off AsO^{3} and
SO^{2}. Sometimes also antimony fumes.

(3) on charcoal. As the preceding, except that a large
quantity of AsO^{3} and but little SbO^{3}
are given off.

(4) in forceps. --

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. As stephanite, except that much arsenic is
given off and but little antimony.

(8) Special reactions. --

* * * * *

Mineral. Horn silver

Formula. AgCl.

Behavior

(1) in glass-bulb. Fuses, but undergoes no further change.

(2) in open tube. --

(3) on charcoal. Fuses readily in the oxidizing flame. In the
reducing flame is slowly reduced yielding
metallic silver.

(4) in forceps. --

(5) in borax. --

(6) in mic. salt. --

(7) with carb. soda. Is rapidly reduced to metallic silver.

(8) Special reactions. If cut up into small pieces mixed with oxide
of copper and then heated before the
oxidizing