Hilary Bauerman

“ With tin it forms a somewhat ductile alloy of a violet colour. The presence of cobalt in the alloy of copper, zinc, and nickel, known as German silver, is objectionable, as it renders it hard and difficult to roll. The chief use of cobalt in the arts is for the preparation of colours. The protoxide has an intense colouring power when vitrified, and forms the basis of all the blue colours used in glass and porcelain manufacture. The purity of the tint is much affected by traces even of other metallic oxides, especially those of iron, nickel, or copper. ”

“ On the large scale cobalt is produced chiefly as an accessory in the treatment of nickel ores. These consist chiefly of mixtures of small quantities of the purer minerals with pyrites, sulphuretted copper ores, or lead and silver ores, which require to be subjected to concentrating processes in order to get rid of the bulk of the iron, sulphur, and arsenic, aud produce a small amount of enriched regulus or metal, in which the more valuable metals are in combination with sulphur and arsenic. ”

“ With ammonia the oxides of cobalt form a series of compound bases, which give rise to salts of great interest and complexity; these may be regarded as ammonium salts, in which part of the hydrogen is replaced by ammonium and another part by cobalt in various conditions of atomicity corresponding to the oxides. The alloys of cobalt are not of much importance. It combines most readily with arsenic or antimony, forming the highly crystalline compounds known by the general name of speiss, which can scarcely be considered as alloys. ”