(f.) Baryta.—­The soluble salts of baryta, moistened, and then submitted to the reduction flame, produce a green color.  The salt should be moistened, when the color will be strongly marked in the outer flame.  The insoluble salts do not produce so vivid a color as the soluble salts, and they are brighter when they have previously been moistened.  The carbonate does not give a strong color, but the acetate does, so long as it is not allowed to turn to a carbonate.  The chloride, when fused on the platinum wire, in the point of the reduction flame, imparts a fine green color to the oxidation flame.  This tint changes finally to a faint dirty green color.  The sulphate of baryta colors the flame green when heated at the point of the reduction flame.  But neither the sulphate, carbonate, nor, in fact, any other salt of baryta, gives such a fine green color as the chloride.  The presence of lime does interfere with the reaction of baryta, but still does not destroy its color.

(g.) Phosphoric Acid.—­The phosphates give a green color to the oxidation flame, especially when they are moistened with sulphuric acid.  This is best shown with the platinum forceps.  The green of phosphoric, or the phosphates, is much less intense than that of the borates or boracic acid, but yet the reaction is a certain one, and is susceptible of considerable delicacy, either with the forceps, or still better upon platinum wire.  Sulphuric acid is a great aid to the development of the color, especially if other salts be present which would be liable to hide the color of the phosphoric acid.  In this reaction with phosphates, the water should be expelled from them previous to melting them with sulphuric acid.  They should likewise be pulverized.  Should soda be present it will only exhibit its peculiar color after the phosphoric acid shall have been expelled; therefore, the green color of the phosphoric acid should be looked for immediately upon submitting the phosphate to heat.

(h.) Molybdic Acid.—­If this acid or the oxide of molybdenum be exposed upon a platinum wire to the point of the reduction flame, a bright green color is communicated to the flame of oxidation.  Take a small piece of the native sulphide of molybdenum, and expose it in the platinum tongs to the flame referred to above, when the green color characteristic of this metal will be exhibited.

(i.) Telluric Acid.—­If the flame of reduction is directed upon a small piece of the oxide of tellurium placed upon charcoal, a bright green color is produced.  Or if telluric acid be submitted to the reduction flame upon the loop of a platinum wire, it communicates to the outer flame the bright green of tellurium.  If the sublimate found upon the charcoal in the first experiment be submitted to the blowpipe flame, the green color of tellurium is produced while the sublimate is volatilized.  If selenium be present the green color is changed to a deep blue one.