A System of Instruction in the Practical Use of the Blowpipe Part 47

(3) on charcoal. Fuses and is reduced affording a bead of metallic lead, and forming an incrustation of PbO on the charcoal. Colors the outer flame blue.

(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 gla.s.s-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 ma.s.s alone remains.

(4) in forceps. --

(5) in borax. The infusible residue obtained upon charcoal gives an iron and sometimes copper and cobalt reaction.

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

(7) with carb. soda. With carbonate of soda, oxalate of potash yields a metallic bead, the fused alkali laid upon silver and moistened produces a stain similar to that produced by sulfur.

(8) Special reactions. --

Mineral. Jamesonite

Formula. [,Pb]^{3}[,,,Sb]^{2}.

Behavior

(1) in gla.s.s-bulb. Fuses and gives off some sulphur, sulphide of antimony and antimony which condense in the neck of the bulb.

(2) in open tube. Fuses and emits dense white fumes of SbO^{3}, which pa.s.s off and redden blue litmus paper.

(3) on charcoal. Fuses with great ease evolving much SbO^{3} and PbO, which incrusts the charcoal around the mineral. When the fumes have ceased, a small bead of metallic lead remains.

(4) in forceps. --

(5) in borax. The yellow incrustation formed upon charcoal gives the reaction of lead, and the white those of antimony.

(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. Minium

Formula. Pb^{3}O^{4}.

Behavior

(1) in gla.s.s-bulb. --

(2) in open tube. --

(3) on charcoal. Is reduced first to litharge (PbO) and then to metallic lead which forms the usual incrustation.

(4) in forceps. Colors the outer flame blue.

(5) in borax. Gives the lead reactions.

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

(7) with carb. soda. As alone on charcoal.

(8) Special reactions. --

Mineral. Mendipite

Formula. PbCl + 2PbO.

Behavior

(1) in gla.s.s-bulb. Decrepitates slightly and a.s.sumes a yellow color.

(2) in open tube. --

(3) on charcoal. Fuses readily and is reduced to metallic lead with the evolution of acid fumes. Forms a white incrustation of PbCl, and a yellow one of PbO.

(4) in forceps. As the preceding.