r
peculiar color to the flame, such as the arseniate of lime.

C. THE GREEN COLOR.

(_a._) _Ammonia._--The salts of ammonia, when heated before the
blowpipe, and just upon the point of disappearing, impart to the flame
a feeble though dark green color. This color, however, can only be
discerned in a dark room.

(_b._) _Boracic Acid._--If any one of the borates is mixed with two
parts of a flux composed of one part of pulverized fluorspar, and four
and a half parts of bisulphate of potash, and after being melted, is
put upon the coil of a platinum wire, and held at the point of the
blue flame, soon after fusion takes place a dark green color is
discerned, but it is not of long duration. The above process is that
recommended by Dr. Turner. The green color of the borates may be
readily seen by dipping them, previously moistened with sulphuric
acid, into the upper part of the blue flame, when the color can be
readily discerned. If soda be present, then the rich green of the
boracic acid is marred by the yellow of the soda. Borax, or the
biborate of soda (NaO, 2BO_{3}) may be used for this latter reaction,
but if it be moistened with sulphuric acid, the green of the boracic
acid can then be seen. If the borates, or minerals which contain
boracic acid, are fused on charcoal with carbonate of potash, then
moistened with sulphuric acid and alcohol, then the bright green of
the boracic acid is produced, even if the mineral contains but a
minute portion of the boracic acid.

(_c._) _Copper_. Nearly all the ores of copper and its salts, give a
bright green color to the blowpipe flame. Metallic copper likewise
colors the flame green, being first oxidized. If iodine, chlorine, and
bromine are present, the flame is considerably modified, but the
former at least intensifies the color. Many ores containing copper
also color the flame green, but the internal portion is of a bright
blue color if the compound contains lead, the latter color being due
to the lead. The native sulphide and carbonate of copper should be
moistened with sulphuric acid, while the former should be previously
roasted. If hydrochloric acid is used for moistening the salts, then
the rich green given by that moistened with the sulphuric acid is
changed to a blue, being thus modified by the chlorine of the acid.
Silicates containing copper, if heated in the flame in the platinum
forceps, impart a rich green color to the outer flame. In fact, if any
substance c