BISMUTH.—­This metal fuses with ease, and under both flames covers the charcoal with a coating of oxide, which, while hot, is of an orange-yellow color, and after cooling, of a lemon-yellow color, passing, at the edges, into a bluish white.  This white coating consists of the carbonate of bismuth.  The sublimate from bismuth is formed at a less distance from the assay than is the case with antimony.  It may be driven from place to place by the application of either flame; but in so doing, the oxide is first reduced by the heated charcoal, and the metallic bismuth so formed is volatilized and reoxidized.  The flame is uncolored.

LEAD.—­This metal readily fuses under either flame, and incrusts the charcoal with oxide at about the same distance from the assay as is the case with bismuth.  The oxide is, while hot, of a dark lemon-yellow color, but upon cooling, becomes of a sulphur yellow.  The carbonate which is formed upon the charcoal, beyond the oxide, is of a bluish-white color.  If the yellow incrustation of the oxide be heated with the flame of oxidation, it disappears, undergoing changes similar to those of bismuth above mentioned.  Under the flame of reduction, it, however, disappears, tinging the flame blue.

CADMIUM.—­This metal fuses with ease, and, in the flame of oxidation, takes fire, and burns with a deep yellow color, giving off brown fumes, which coat the charcoal, to within a small distance of the assay, with oxide of cadmium.  This coating exhibits its characteristic reddish-brown color most clearly when cold.  Where the coating is very thin, it passes to an orange color.  As oxide of cadmium is easily reduced, and the metal very volatile, the coating of oxide may be driven from place to place by the application of either flame, to neither of which does it impart any color.  Around the deposit of oxide, the charcoal has occasionally a variegated tarnish.

ZINC.—­This metal fuses with ease, and takes fire in the flame of oxidation, burning with a brilliant greenish-white light, and forming thick white fumes of oxide of zinc, which coat the charcoal round the assay.  This coating is yellow while hot, but when perfectly cooled, becomes white.  If heated with the flame of oxidation, it shines brilliantly, but is not volatilized, since the heated charcoal is, under these circumstances, insufficient to effect its reduction.  Even under the reducing flame, it disappears very slowly.

TIN.—­This metal fuses readily, and, in the flame of oxidation, becomes covered with oxide, which, by a strong blast, may be easily blown off.  In the reducing flame, the fused metal assumes a white surface, and the charcoal becomes covered with oxide.  This oxide is of a pale yellow color while hot, and is quite brilliant when the flame of oxidation is directed upon it.  After cooling, it becomes white.  It is found immediately around the assay, and cannot be volatilized by the application of either flame.