cooling process, the colors change more rapidly than with borax.

in the reducing flame.

With a small proportion of oxide there is no reaction. With a
larger amount the bead is red, while warm, and becomes on
cooling successively yellow, green, and russet. With the
addition of tin the glass becomes, during cooling, first green
and then colorless.

* * * * *

6. Oxide of Cobalt, CoO.

Behavior with Borax on Platinum wire

in the oxidizing flame:

Colors the glass of an intense smalt blue both whilst hot and
when cold. When much oxide is present, the color is so deep as
to appear black.

in the reducing flame:

As in the oxidizing flame.

Behavior with Mic. Salt on Platinum wire

in the oxidizing flame.