In the flame of reduction the bead becomes of a dirty green color, being partly reduced to protoxide, and appears, with a certain degree of saturation, black, when heated intermittingly, but never enamelled. The bead appears on charcoal, and with the addition of tin, of a dark green color.
It fuses with microcosmic salt in the oxidation flame to a clear yellow bead, which is greenish-yellow when cold. In the reduction flame it produces a beautiful green bead, which increases when cold.
When fused upon charcoal with the addition of tin, its color is darker. Carbonate of soda does not dissolve it, although with a very small portion of soda it gives indications of fusion, but with still more of the soda it forms a yellow, or light-brown mass, which is absorbed by the charcoal, but it is not reduced to the metallic state.
(i.) Vanadium (V).—This very rare mineral is found in small quantity in iron-ores, in Sweden, and as vanadic acid in a few rare minerals. The metal presents the appearance of an iron-grey powder, and sometimes that of a silver-white mass. It is not oxidized either by air or water, and is infusible.
Vanadic Acid (VO3) fuses upon platinum foil to a deep orange liquid, which becomes crystalline after cooling. When fused upon charcoal, one part of it is absorbed, while the rest remains upon the charcoal and is reduced to protoxide similar in appearance to graphite.
A small portion of it fuses with borax in the oxidation flame to a clear colorless bead, which appears, with the addition of more vanadic acid, of a yellow color, but changes to green when cold.
In the reduction flame the bead is brown while hot, but changes, upon cooling, to a beautiful sapphire-green. At the moment of crystallization, and at a degree of heat by which at daylight no glowing of the heated mass is visible it begins to glow again. The glow spreads from the periphery to the centre of the mass, and is caused by the heat liberated by the sudden crystallization of the mass. It now exhibits an orange color, and is composed of needle crystals in a compact mass.
Microcosmic salt and vanadic acid fuse in the oxidation flame to a dark yellow bead which, upon cooling, loses much of its color.
In the reduction flame the bead is brown while hot, but, upon cooling, acquires a beautiful green color.
Vanadic acid fuses with carbonate of soda upon charcoal, and is absorbed.