the eye becomes familiarized with the appearances of their
incrustations upon charcoal.

The greater part of the metals fuse when submitted to the heat of the
blowpipe, and if exposed to the outer flame, they oxidize. These
metals, termed the noble metals, do not oxidize, but they fuse. The
metals platinum, iridium, rhodium, osmium and palladium do not fuse.
The metal osmium, if exposed to the flame of oxidation, fuses and is
finally dissipated as osmic acid. In the latter flame, the salts of
the noble metals are reduced to the metallic state, and the charcoal
is covered with the bright metal.

We shall give a brief description of the appearance of the principal
elementary bodies upon being fused with charcoal. This plan is that
deemed the most conducive to the progress of the student, by
Berzelius, Plattner, and Sherer. Experience has taught us that this
method is the most efficient that could have been devised as an
initiatory exercise for the student, ere he commences a more concise
and methodical method of analysis. In these reactions upon charcoal,
we shall follow nearly the language of Plattner and Sherer.

SELENIUM is not difficult of fusion, and gives off brown fumes in
either the oxidation or reduction flame. The deposit upon the charcoal
is of a steel-grey color, with a slightly metallic lustre. The deposit
however that fuses outside of this steel-grey one is of a dull violet
color, shading off to a light brown. Under the flame of oxidation this
deposit is easily driven from one portion of the charcoal to another,
while the application of the reducing flame volatilizes it with the
evolution of a beautiful blue light. The characteristic odor of
decayed horse-radish distinguishes the volatilization of this metal.