A System of Instruction in the Practical Use of the Blowpipe Part 11

Behavior with Mic. Salt on Platinum wire

in the oxidizing flame.

Dissolves to a clear yellow gla.s.s, which a.s.sumes a yellowish-green color on cooling.

in the reducing flame.

The gla.s.s a.s.sumes a beautiful green color, which becomes more brilliant as the bead cools. The addition of tin upon charcoal produces no further change.

14. Oxide of Copper, CuO.

Behavior with Borax on Platinum wire

in the oxidizing flame.

Produces an intense coloration. If in small quant.i.ty, the gla.s.s is green, while warm, and becomes blue on cooling. If in large proportion, the green color is so intense as to appear black.

When cool, this becomes paler, and changes to a greenish blue.

in the reducing flame.

If not too saturated, the cupriferous gla.s.s soon becomes nearly colorless, but immediately on solidifying a.s.sumes a red color and becomes opaque. By long continued blowing on charcoal, the copper in the bead is reduced and separates out as a small metallic bead, leaving the gla.s.s colorless. With the addition of tin, the gla.s.s becomes of an opaque dull-red on cooling.

Behavior with Mic. Salt on Platinum wire

in the oxidizing flame.

With an equal proportion of oxide, this salt is not so strongly colored as borax. A small amount imparts a green color in the warm and a blue in the cold. With a very large addition of oxide, the gla.s.s is opaque in the hot state, and after cooling of a greenish-blue.

in the reducing flame.

A tolerably saturated gla.s.s a.s.sumes a dark green color under a good flame, and on cooling becomes of an opaque brick-red, the moment it solidifies. A gla.s.s containing but a small proportion of the oxide becomes equally red and opaque on cooling, if treated with tin upon charcoal.

15. Oxide of Mercury, HgO.

Behavior with Borax on Platinum wire

in the oxidizing flame.

No reaction.

in the reducing flame.

No reaction.

Behavior with Mic. Salt on Platinum wire

in the oxidizing flame.

No reaction.

in the reducing flame.

No reaction.

16. Oxide of Silver, AgO.

Behavior with Borax on Platinum wire

in the oxidizing flame.

The oxide is partly dissolved and partly reduced. In small quant.i.ty, it colors the gla.s.s yellow while warm, the color disappearing on cooling. In larger quant.i.ty, the gla.s.s is yellow while warm, but during cooling becomes paler to a certain point, and then again deeper. If reheated slightly, the gla.s.s becomes opalescent.

in the reducing flame.

On charcoal the argentiferous gla.s.s becomes at first grey from the reduced metal, but afterwards, when the silver is collected into a bead, it becomes clear and colorless.

Behavior with Mic. Salt on Platinum wire

in the oxidizing flame.

Both the oxide and the metal afford a yellowish gla.s.s, which, when containing much oxide becomes opaline, exhibiting a yellow color by daylight and a red one by artificial light.

in the reducing flame.

As in borax.

17. Oxide of Platinum, PtO^{2}.

18. Oxide of Palladium, PdO^{2}.

19. Oxide of Rhodium, R^{2}O^{3}.

20. Oxide of Iridium, Ir^{2}O^{3}.

21. Oxide of Ruthenium, Ru^{2}O^{9}.

22. Oxide of Osmium OsO^{2}.

Behavior with Borax on Platinum wire

in the oxidizing flame.

Are reduced without being dissolved. The reduced metal, being infusible, cannot however be collected into a bead.

in the reducing flame.