it
melts. Lithia or its salts, exposed to the point of the blue flame,
communicates a red color to the external or oxidation flame, in
consequence of a reduction, sublimation, and re-oxidation of the
lithia. An admixture of potash communicates to this flame a
reddish-violet color, and the presence of soda that of a yellowish-red
or orange. If the soda, however, is in too great proportion, then its
intense yellow hides the red of the lithia. In the latter case the
substance under test must be only imperfectly fused in the oxidation
flame, and then dipped in wax or tallow. By exposing it now to the
reduction flame, the red color imparted to the external flame by the
lithia becomes visible, even if a considerable quantity of soda be
present. A particular phenomenon appears with the phosphate of lithia,
viz., the phosphoric acid itself possesses the property of
communicating to the flame a bluish-green color. By its combination
with lithia it still exhibits its characteristic color, while the
latter presents likewise its peculiar tint. Then we perceive a green
flame in the centre of the flame, while the red color of lithia
surrounds it.

The _silicates_, which contain only a little lithia, produce only a
slight hue in the flame, and often none at all. We have to mix one
part of the silicate with two parts of a mixture composed of one part
of fluorspar and one and a half parts of bisulphate of potassa.
Moisten the mass with water so that the mass will adhere, and then
melt it upon a platinum wire in the reduction flame, when that of
oxidation will present the red color of lithia.

The _Borates of lithia_ produce at first a green color, but it soon
yields to the red of lithia. When alcohol is poured over lithia or its
compounds, and inflamed, it burns with a deep red color, particularly
if the fluid is stirred up with a glass rod, or when the alcohol is
nearly consumed. This color presents the same modifications as the
corresponding ones communicated to the blowpipe as mentioned above.

The salts of lithia are absorbed by charcoal when fused upon it. The
sulphide, bromide, iodide, and chloride of lithia produce upon the
charcoal a greyish-white sublimate, although not so copiously as the
corresponding compounds of potash and soda. This sublimate disappears
when touched by the reduction flame, while the oxidation flame gives
the characteristic color of lithia.

SECOND GROUP.--THE ALKALINE EARTHS, BARYTA, STRONTIA, LIME