Hartley — On the Constitution of Nitric Acid and its Hydrates. 377 



position of this had become 54*68 per cent. HN0 3 and 45*32 per 

 cent. H 2 0, which corresponds to a monohydrated orthonitric acid 

 N(OH) 3 • H 2 0, the same as that isolated by Pickering, m. p. 

 - 18°*0. It continues, however, to absorb water. 



Note. — On May 26th, 1905, after an interval of more than 

 five months from December 16th, during which the temperature 

 never exceeded 17°*5 C, the acid was found to have become 

 reduced in specific gravity to 1-187 at 15° C, and it contained 

 29*56 per cent, of HN0 3 . It is improbable that this acid will 

 undergo any further change in composition under normal atmo- 

 spheric conditions. 



H 2 



