(4) in forceps. --

(5) in borax. The oxide formed upon charcoal gives the lead
reaction.

(6) in mic. salt. As in borax.

(7) with carb. soda. As alone on charcoal. The fused alkali gives a
sulphur reaction on silver.

(8) Special reactions. --

* * * * *

Mineral. Clausthalite

Formula. PbSe.

Behavior

(1) in glass-bulb. Decrepitates slightly.

(2) in open tube. Forms a sublimate of selenium, which is grey
when thickly deposited, and red when thin.

(3) on charcoal. Gives off fumes smelling strongly of selenium
and coloring the flame blue. In the reducing
flame fuses partially and incrusts the charcoal
with Se and PbO. After some time a black
infusible mass alone remains.