193 



a certain variation, due, perhaps, to a magnetic or diamagnetic con- 

 dition, the appearance of the earth in what Mr Nasmyth calls its 

 " pre-oceanic" state; when, still incandescent, the ocean could find no 

 resting-place on its surface, but would have been compelled to form 

 a dense vapour envelope in the atmosphere ; of frozen particles out- 

 side, by reason of the coldness of space, and of watery vapour inside, 

 from the radiation of heat from the hot internal globe. 



2. Chemical Notices. By Professor Gregory. 



1. On the new compounds of Cobalt described by Fremy 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. Fremy, 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 ammo- 

 nia, 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. I shall not enter farther into any 

 details of the views of Fremy, in regard to many of these salts, 

 which are very complicated, and confessedly provisional. But I have 

 made some experiments on the formation and analysis of two of the 

 most remarkable of the salts described by him, one of which belongs 

 to the series of Roseocobaltiak, the other to that of Luteocobaltiak. 

 Both are chlorides or hydrochlorates, and the former, or the pink 

 salt, is the same as was described by Claudet and Genth. I find 

 that both this and the other — which is yellow, a very unexpected fact 

 in compounds of cobalt — may easily be obtained by dissolving proto- 

 chloride of cobalt in water, adding sal-ammoniac and an excess of 

 ammonia, and passing chlorine through the solution, till the chlorine 

 is in excess. It then deposits a mixed mass of pink and yellow salt, 

 which may be separated by the greater solubility of the yellow salt 

 in water very slightly acidulated with hydrochloric acid, in which the 

 pink salt is almost insoluble. The yellow salt may be obtained in 

 large and fine crystals by spontaneous evaporation. When large, 

 the crystals are of a deep orange-red, but the powder and the small 

 crystals are bright orange-yellow. The red salt is sparingly so- 

 luble in hot water, which, on cooling, deposits it in dark red crys- 



