Analysis by Spectrum-observations. 501 



attacks glass and platinum. In absolute alcohol the salt is very 

 slightly soluble*. 



Nitrate of csesium is somewhat more difficultly soluble in 

 water than the corresponding potassium compound ; for whilst 

 100 parts of water at + 3 0, 2 C. dissolve 16-1 parts of the latter, 

 10*58 parts of nitrate of ca3sium are dissolved under similar cir- 

 cumstances. 



3-0567 grms. of pure nitrate of caesium gave 2*8233 grins, of 

 the sulphate on decomposition and ignition with sulphuric acid. 

 Hence the composition of the salt is — 



Calculated. Found. 



CsO ". . . 131*35 70*87 70*80 



NO 5 . . . 54*00 29*13 29*20 



185-35 10000 100*00 



f. Bisulphate of Casium. 

 Carbonate of csesium is gradually heated with an excess of 

 sulphuric acid until the temperature rises nearly to redness. The 

 salt then consists of a transparent colourless liquid, which, on 

 cooling, solidifies to a crystalline mass. Dissolved in water, the 

 acid salt thus obtained crystallizes upon slow evaporation in the 

 form of small short rhombic prisms, having rectangular termina- 

 tions, and having the acute longitudinal edges equally bevelled. 

 The crystals belong to the rhombic system. The relation of the 

 horizontal axes is nearly 



a:i=l:l-38. 

 The crystals obtained were badly formed, and their surfaces were 

 not polished enough to enable us to make any accurate measure- 

 ments with the reflecting goniometer. The relation of the prin- 

 cipal axis to the horizontal axes could also not be obtained, as no 

 faces were visible on the terminal edges of the prism. The cry- 

 stals are represented by fig. 3, Plate V. 



Found. Calculated. 



p-p on a ... 107 37 108° 



p-b 126 



The salt has a strongly acid reaction and taste ; it is, however, 

 unalterable in the air. Heated gently, it melts quietly under a 

 red heat ; and when more strongly ignited, sulphuric anhydride 

 escapes with effervescence, leaving a solid mass of neutral sul- 

 phate of caesium, which melts at a temperature approaching a 

 yellow heat. 



* Saltpetre is by no means insoluble in alcohol, as Berzelius affirms. 

 The slight solubility of the caesium nitrate in alcohol cannot, therefore, be 

 used, as one of us formerly proposed, as a distinctive reaction of these two 

 salts. 



