(4) in forceps. --
(5) in borax. The oxide formed upon charcoal gives the bis.m.u.th reactions.
(6) in mic. salt. As in borax.
(7) with carb. soda. --
(8) Special reactions. --
Mineral. Bis.m.u.thine
Formula. BiS.
Behavior
(1) in gla.s.s-bulb. --
(2) in open tube. Fuses with ebullition and gives of S and SO^{2}.
(3) on charcoal. Fuses with much spirting and in the reducing flame yields a metallic bead and incrusts the charcoal with oxide.
(4) in forceps. --
(5) in borax. The oxide obtained upon charcoal gives the bis.m.u.th reactions.
(6) in mic. salt. As in borax.
(7) with carb. soda. As alone on charcoal. The fused alkali gives the sulphur reaction on silver.
(8) Special reactions. --
Mineral. Bis.m.u.thblende
Formula. [...Bi=]^{2}[...Si]^{3}.
Behavior
(1) in gla.s.s-bulb. Turns yellow and, when strongly heated, fuses.
(2) in open tube. --
(3) on charcoal. Fuses with ebullition to a brown globule forming an incrustation of [...Bi=] on the charcoal.
(4) in forceps. I. Fuses with ease to a yellow bead, coloring the outer flame bluish green, especially if moistened with HCl. This color is due to [.....P].
(5) in borax. Gives the bis.m.u.th and also an iron reaction.
(6) in mic. salt. As in borax, but leaves a silicious skeleton.
(7) with carb. soda. Fuses to a yellow ma.s.s. The bis.m.u.th is then reduced to the metallic state and partially volatilized, incrusting the charcoal beyond.
(8) Special reactions. --
Mineral. Tetradymite
Formula. Bi, Te, S.
Behavior
(1) in gla.s.s-bulb. Occasionally decrepitates and then fuses, forming a greyish white sublimate immediately above the mineral fragment.
(2) in open tube. Fuses and gives off white fumes, part of which pa.s.s up the tube and part deposit immediately above the mineral. This latter if heated fuses to clear drops (TeO^{3}). The mineral residue becomes surrounded by fused [...Bi=], characterized by its yellow color.
(3) on charcoal. Fuses to a metallic bead, colors the outer flame bluish green (Te and Se) and incrusts the charcoal around with the orange [...Bi=], beyond which is a white incrustation partly consisting of [...Te].
(4) in forceps. --
(5) in borax. The yellow oxide obtained upon charcoal gives the bis.m.u.th reaction, and the white incrustation of bis.m.u.th and telluric acid.
(6) in mic. salt. As in borax.
(7) with carb. soda. In the reducing flame yields a bead of metallic bis.m.u.th, part of which is part of the tellurium volatilized and incrusts the charcoal around.
(8) Special reactions. The fused alkaline ma.s.s gives the sulphur reaction on silver. Also gives the tellurium reaction with charcoal and carbonate of soda.
LEAD.
Mineral. Galena
Formula. PbS.
Behavior
(1) in gla.s.s-bulb. Generally decrepitates and gives off a small quant.i.ty of sulphur.
(2) in open tube. Gives off SO^{2}, and when strongly heated, a white sublimate of [.Pb], [.S].