r, if iron be in
considerable quantity, renders it green.

* * * * *

30. Molydbic Acid, MO^{3}.

Behavior with Borax on Platinum wire

in the oxidizing flame.

Dissolves readily and in large quantity. When but little is
dissolved, the glass is yellow while hot and colorless when
cold. When in larger quantity yellow while warm and opaline when
cold, and a further addition of acid renders it yellow when
warm, the color, on cooling, changing first to a pale enamel
blue, and then to an enamel white.

in the reducing flame.

The glass, which has been treated in the oxidizing flame,
becomes, when the acid is not present in too large a quantity,
brown, and when in large quantity, perfectly opaque. In a
strong flame, oxide of molybdenum is formed which is visible in
the yellow glass in the form of black flakes. If the glass
appear opaque, it should be flattened with the forceps.

Behavior with Mic. Salt on Platinum wire

in the oxidizing flame.

Dissolves to a clear glass, which, when sufficient acid is
present, is of a yellowish-green color when warm, and becomes
nearly colorless on cooling. On charcoal, the glass becomes
dark, and when cool has a beautiful green color.

in the reducing flame.

The glass becomes of a bottle-green color, which on cooling,
changes to a brilliant green, similar to that produced by oxide
of chromium. The reaction on charcoal is precisely similar. Tin
renders the color somewhat darker.

* * * * *

31. Vanadic Acid, VaO^{8}.

Behavior with Borax on Platinum wire

in the oxidizing flame.

Dissolves to a clear glass, which is colorless when only a small
quantity of acid is present, and yellow when containing a larger
proportion.

in the reducing flame.

The yellow color of the glass changes to a brown when warm and a
chrome-green on cooling.

Behavior with Mic. Salt on Platinum wire

in the oxidizing flame.

As with borax.

in the reducing flame.

As with borax.

* * * * *

32. Oxide of Chromium, Cr^{2}O^{3}.

Behavior with Borax on Platinum wire

in the oxidizing flame.

Affords an intense color, but dissolves slowly. A small
proportion colors t