SALTS 



g. Bisulphate of cobalt. When sulphate of 

 cobalt is crystallized in an excess of acid, long 

 four-sided prisms are obtained, which speedily 

 effloresce on the surface when exposed to the 

 air, but do not fall to powder. These crystals 

 contain twice as much acid as the neutral salt, 

 and are composed of 



2 atoms sulphuric acid 



1 atom protoxide of cobalt 



3 atoms water 



17-625 



Nitrate, 3t Nitrate of cobalt. This salt is easily ob- 

 tained by dissolving cobalt or its oxide in nitric 

 acid. The solution has a deep red colour, and 

 when sufficiently concentrated, deposites crys- 

 tals of nitrate of cobalt, which have a red colour 

 with a shade of brown. They seem to be rhom- 

 boids, but are always so interwoven and irregu- 

 lar, that it is difficult to recognise the true form. 

 They deliquesce rather rapidly when exposed to 

 the air. Their taste is acrid and bitter, and 

 they redden vegetable blues. 



17*75 grains of the crystals of this salt were 

 heated in a platinum crucible. In a moderate 

 heat they melted in their water of crystallization, 

 and continued for a considerable time to give 

 out nothing but pure water. At last when the 

 greatest part of the water was dissipated, and 



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