arcoal, and
then upon the bead itself, covering it with white, pearly crystals.
The phenomenon is dependent upon the fact, that the heated button of
antimony, in absorbing oxygen from the air, developes sufficient heat
to maintain the metal in a fluid state, until it becomes entirely
covered with crystals of antimonious acid so formed.

BISMUTH.--This metal fuses with ease, and under both flames covers the
charcoal with a coating of oxide, which, while hot, is of an
orange-yellow color, and after cooling, of a lemon-yellow color,
passing, at the edges, into a bluish white. This white coating
consists of the carbonate of bismuth. The sublimate from bismuth is
formed at a less distance from the assay than is the case with
antimony. It may be driven from place to place by the application of
either flame; but in so doing, the oxide is first reduced by the
heated charcoal, and the metallic bismuth so formed is volatilized and
reoxidized. The flame is uncolored.

LEAD.--This metal readily fuses under either flame, and incrusts the
charcoal with oxide at about the same distance from the assay as is
the case with bismuth. The oxide is, while hot, of a dark lemon-yellow
color, but upon cooling, becomes of a sulphur yellow. The carbonate
which is formed upon the charcoal, beyond the oxide, is of a
bluish-white color. If the yellow incrustation of the oxide be heated
with the flame of oxidation, it disappears, undergoing changes similar
to those of bismuth above mentioned. Under the flame of reduction,
it, however, disappears, tinging the flame blue.

CADMIUM.--This metal fuses with ease, and, in the flame of oxidation,
takes fire, and burns with a deep yellow color, giving off brown
fumes, which coat the charcoal, to within a small distance of the
assay, with oxide of cadmium. This coating exhibits its characteristic
reddish-brown color most clearly when cold. Where the coating is very
thin, it passes to an orange color. As oxide of cadmium is easily
reduced, and the metal very volatile, the coating of oxide may be
driven from place to place by the application of either flame, to
neither of which does it impart any color. Around the deposit of
oxide, the charcoal has occasionally a variegated tarnish.

ZINC.--This metal fuses with ease, and takes fire in the flame of
oxidation, burning with a brilliant greenish-white light, and forming
thick white fumes of oxide of zinc, which coat the charcoal round the
assay. This coating