reduced antimony, but by continued blowing is restored to
clearness. Even when the glass contains but little oxide, tin
produces this reaction.

* * * * *

29. Tungstic Acid, WO^{3}.

Behavior with Borax on Platinum wire

in the oxidizing flame.

Dissolves readily to a clear colorless glass. In large
proportion it renders the borax yellow, while warm, and with a
still greater addition the bead may be made opaque with an
intermittent flame. If more be then added, this reaction takes
place spontaneously.

in the reducing flame.

When the oxide is present in small quantity, the glass undergoes
no change. With a larger proportion, the glass is deep yellow
while warm, and yellowish-brown when cold. This reaction takes
place upon charcoal, with a small quantity of the acid. Tin
produces a dark coloration, when the acid is not present in too
great a quantity.

Behavior with Mic. Salt on Platinum wire

in the oxidizing flame.