1. On the new compounds of Cobalt described by Frémy and others.

Claudet in London, and Genth in Germany, about the same time observed a new compound of cobalt, with the elements of ammonia and chlorine. Frémy, about the same time, announced a far more extended investigation, the result of which was the discovery of no less than five series of salts, in some of which the base, with oxygen acids, was formed of oxides of cobalt along with more or less ammonia, and, with hydrogen acids, was formed of cobalt with more or less ammonia. In other series, salts of oxides of cobalt, for the most part previously unknown oxides of this metal, seem to have combined with more or less ammonia.