A System of Instruction in the Practical Use of the Blowpipe Part 49

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

(8) Special reactions. Gives the chlorine reaction.

Mineral. Vanadinite

Formula. PbCl + 3[.Pb]^{3}[...V]?

Behavior

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

(2) in open tube. --

(3) on charcoal. The powdered mineral fuses fuses to a black s.h.i.+ning ma.s.s, which in the reducing flame affords a metallic bead. Incrusts the charcoal first with a white film of PbCl and afterwards with PbO.

(4) in forceps. As pyromorphite.

(5) in borax. Dissolves readily to a clear gla.s.s, which, in the oxidizing flame, is yellow, while hot, and colorless when cold. In reducing flame becomes opaque, and on cooling green.

(6) in mic. salt. In oxidizing flame is yellow while hot, becoming paler on cooling. In reducing flame brown while warm, and emerald green when cold.

(7) with carb. soda. On platinum wire fuses to a yellow bead, which is crystalline on cooling. On charcoal yields a b.u.t.ton of metallic lead.

(8) Special reactions. With microcosmic salt and CuO, gives the chlorine reaction. If fused in a platinum spoon with from 3 to 4 times its volume of [.K],[...S]^{2} it forms a fluid yellow ma.s.s having an orange color when cold.

Mineral. Crocoisite

Formula. [.Pb][...Cr].

Behavior

(1) in gla.s.s-bulb. Decrepitates violently and a.s.sumes a dark color.

(2) in open tube. --

(3) on charcoal. Fuses and detonates yielding Cr^{2}O^{3} and metallic lead, and forming an incrustation of PbO on the charcoal.

(4) in forceps. As pyromorphite.

(5) in borax. Dissolves readily and colors the gla.s.s yellow while warm, and green when cold. (See Chromium reaction.)

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

(7) with carb. soda. On platinum foil gives a dark yellow ma.s.s, which becomes paler on cooling. On charcoal yields a metallic b.u.t.ton.

(8) Special reactions. Treated as above with [.K],[...S]^{2} forms a violet colored ma.s.s, which on solidifying becomes reddish and on cooling pale grey.

Mineral. Molybdate of lead

Formula. [.Pb][...M].

Behavior

(1) in gla.s.s-bulb. As the preceding.

(2) in open tube. --

(3) on charcoal. Fuses and is partly absorbed into the charcoal leaving a globule of metallic lead, which is partially oxidized and incrusts the charcoal.

(4) in forceps. As pyromorphite.

(5) in borax. Dissolves readily and gives the molybdena reaction.

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

(7) with carb. soda. Yields metallic lead.

(8) Special reactions. Fused as above with [.K],[...S]^{2} forms a yellow ma.s.s, which becomes white on cooling. If this be dissolved in water and a piece of zinc introduced into the solution, the latter becomes blue.

Mineral. Scheeletine

Formula. [.Pb][...W].

Behavior

(1) in gla.s.s-bulb. Decrepitates more or less.

(2) in open tube. --

(3) on charcoal. Fuses to a bead incrusting the charcoal with PbO. The bead on cooling is crystalline and has a dark metallic surface.

(4) in forceps. As pyromorphite.

(5) in borax. Dissolves to a clear colorless gla.s.s, which in the reducing flame becomes yellow, and on cooling grey and opaque.

(6) in mic. salt. Dissolves to a clear colorless gla.s.s, which in the reducing flame a.s.sumes a dusky blue color. After a time becomes opaque.

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