A System of Instruction in the Practical Use of the Blowpipe Part 51

(8) Special reactions. If the copper bead obtained by fusing upon carbonate of soda be cupelled with a.s.say lead, a silver bead will be obtained. Or if dissolved in nitric acid and a drop or two of HCl added, a white precipitate of AgCl will be formed, which may be collected and reduced with carbonate of soda upon charcoal.

Mineral. Tennat.i.te

Formula. ([,Cu=][,Fe=])^{4}[,,,As].

Behavior

(1) in gla.s.s-bulb. Decrepitates occasionally and gives a red sublimate of [,,,As].

(2) in open tube. Evolves [..S] and [...As], which condense and form a white sublimate.

(3) on charcoal. Fuses to a magnetic bead giving of a.r.s.enical and sulphurous fumes.

(4) in forceps. --

(5) in borax. As the preceding.

(6) in mic. salt. As the preceding.

(7) with carb. soda. Yields a copper bead and metallic iron in the form of a dark grey powder. The fused alkali gives the sulphur reaction.

(8) Special reactions. --

Mineral. Bournonite

Formula. ([,Pb]^{2}[,Cu=])[,,,Sb].

Behavior

(1) in gla.s.s-bulb. Decrepitates giving off sulfur and, when strongly heated, [,,,Sb] and [...Sb].

(2) in open tube. Evolves thick white fumes of [...Sb],[.....Sb]

and [.Pb][...Sb]. Also [.S].

(3) on charcoal. Fuses readily and incrusts the charcoal with [...Sb] and [.Pb] leaving a dark colored bead.

(4) in forceps. --

(5) in borax. If the bead obtained on charcoal be fused on that support in the reducing flame with borax, a slight iron reaction is obtained, and after a time a copper reaction.

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

(7) with carb. soda. Yields a bead of metallic copper and lead and incrusts the charcoal with [...Sb] and [.Pb].

The alkaline ma.s.s laid on silver and moistened gives the sulphur reaction.

(8) Special reactions. --

Mineral. Red oxide of copper

Formula. Cu^{2}O

Behavior

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

(2) in open tube. Is converted into the black oxide CuO.

(3) on charcoal. In the reducing flame is reduced, forming a bead of metallic copper.

(4) in forceps. Fuses and colors the the flame emerald green, or if previously moistened with HCl, blue.

(5) in borax. Gives the copper reaction.

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

(7) with carb. soda. Is reduced to a bead of metallic copper.

(8) Special reactions. --

Mineral. Atacamite

Formula. CuCl + 3[.Cu] + 6[.H].

Behavior

(1) in gla.s.s-bulb. Gives off much water, having an acid reaction, on test paper, and forms a light grey sublimate of CuCl.

(2) in open tube. --

(3) on charcoal. Fuses, colors the flame blue, forms a brown and a pale grey incrustation on the charcoal, and is reduced to metallic copper, leaving a small quant.i.ty of slag.

(4) in forceps. Fuses and colors the outer flame intensely blue and green towards the point.

(5) in borax. Gives the copper reactions.

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

(7) with carb. soda. Is reduced, yielding a bead of metallic copper.