Kobalt, (Germ.) called also cadmia metallic*. Cobalt. It is a ponderous hard metallic substance, found in some parts of Asia, now chiefly dug up in Saxony, but also met with in England. The best way of distinguishing it from other minerals is to melt it with glass, for it imparts a sapphire blue colour: from it the greatest quantity of arsenic is obtained that is used all over Europe.
When dug, it is mixed with various other substances; it is then broken into small pieces, and calcined in a reverberatory furnace, so formed as that the flame of the fire may pass over the calcining matter, and keep it ignited: the flame, in passing over the cobalt, carries off a copious fume, which is conveyed from the top of the furnace into a large long winding wooden chimney, to the inside of which the fumes adhering in the form of a white soot, are at proper intervals swept down, and when melted form the white arsenic. The cobalt is next repeatedly calcined, and then finely ground with two or three times its weight of powdered flint. From this mixture, when melted, zaffer is produced.
If two parts of calcined cobalt, one part of potash, and three parts of common sand, are melted together, a vitreous opaque, bluish mass is formed, which, when ground to powder, is called smalt, or encaustum caeru-leum, powder blue.
On the outside of the mines where cobalt is found, there is a mineral of the colour of streaked roses, called the flower of cobalt.
The chief use of this mineral is for obtaining arsenic, and the reguline part is the blue made use of for colouring glass or china. See Lewis's Mat. Med. Dictionary of Chemistry, and Neumann's Chem. Works.