Antimony gives a white sublimate when its salts are roasted, as the sulphide, or the antimonides themselves, or the oxide of this metal.  This white sublimate is not antimonious acid, but there is mixed with it the oxide of antimony with which the acid is sublimed.  As is the case with arsenious acid, the antimonious acid may, by dexterous heating, be driven from one portion of the tube to another.

Tellurium, or its acid and oxide, may be got as a sublimate in the tube.  The tellurious acid, unlike the arsenious and antimonious acids, cannot be driven from one portion of the tube to another, but, on the contrary, it fuses into small clear globules, visible to the naked eye sometimes, but quite so with the aid of the magnifying glass.

Lead, or its chloride, sublimes like tellurium, and, like that substance, fuses into globules or drops.

Bismuth, or its sulphide, sublimes into an orange or brownish globules, when it is melted, as directed above, for tellurium.  The color of the bismuth and lead oxides are somewhat similar, although that of the latter is paler.

If any mineral containing fluorine, is fused, first with the microcosmic salt bead, then put into the tube, and the flame of the blowpipe be directed into the tube upon the bead, hydrofluoric acid is disengaged and attacks the inside of the tube.  The fluoride of calcium, or fluorspar, may be used for this experiment.

During the roasting, a brisk current of air should be allowed to pass through the tube, whereby unoxidized matter may be prevented from volatilization, and the clogging up of the substance under examination be prevented.

3.  EXAMINATIONS UPON CHARCOAL.

In making examinations upon charcoal, it is quite necessary that the student should make himself familiar with the different and characteristic appearances of the deposits upon the charcoal.  In this case I have found the advice given by Dr. Sherer to be the best; that is, to begin with the examination of the pure materials first, until 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.