when fused with them; therefore, it not only directly combines with
oxides, but it expels, by fusion, all other volatile acids from their
salts. Furthermore, boracic acid promotes the oxidation of metals and
sulphur, and induces haloid compounds, in the oxidation flame, to
combine with the rising oxides. Borates thus made, melt generally by
themselves; but admixed with borate of soda, they fuse much more
readily, give a clear bead. Borax acts either as a flux, or through
the formation of double salts.

In borax, we have the action of free boracic acid, as well as borate
of soda, and for that reason it is an excellent reagent for blowpipe
analysis.

All experiments in which borax is employed should be effected upon
platinum wire. The hook of the wire should be heated red hot, and then
dipped into the powdered borax. This should be exposed to the
oxidation flame, when it will be fused to a bead, which adheres to the
hook. This should be then dipped into the powdered substance, which
will adhere to it if it is hot; but if the bead is cool, it must be
previously moistened. Expose this bead to the oxidation flame until it
ceases to change, then allow it to cool, when it should be exposed to
the reduction flame. Look for the following in the oxidation flame:

(1.) Whether the heated substance is fused to a clear bead or
not, and whether the bead remains transparent after cooling. The
beads of some substances, for instance those of the alkaline
earths, are clear while hot; but upon cooling, are milk-white and
enamelled. Some substances give a clear bead when heated and when
cold, but appear enamelled when heated intermittingly or with a
flame which changes often from oxidation to reduction, or with an