182 Scientific Intelligence. 



sistence, and of the specific gravity 1.831, floated over the more solid 

 part. 



The crystalline portion of the mass, from which the liquid had been 

 drained, but which still continued a soft solid, was intensely acid to the 

 taste, and when handled, stained the fingers like strong nitrous acid. When 

 added to water, a rise of temperature of more than 60° F. was produced, 

 and a violent effervescence took place, accompanied with red fumes, re- 

 sembling those of nitrous gas when escaping into the atmosphere. A si- 

 milar extrication of gas was observed, on pouring the deliquiated portion 

 of the mass into water. By collecting the gas in a pneumatic trough, it 

 was found to be nitrous gas of remarkable purity. 



The crystalline substance sustained a heat of 220° F. for more than an 

 hour, without parting with any gas ; but at 280°, nitrous gas was evolved. 

 A temperature, however, of 400° did not entirely decompose it ; for the 

 liquid which remained, when poured into water, gave abundance of nitrous 

 gas. The proportion of that gas which could be expelled by heating the 

 solid salt, exceeded what was evolved from the same quantity by solution 

 in water. Besides the permanent gas, a vapour was also separated by heat, 

 which was evidently nitrous acid, since it tinged a few drops of water con- 

 tained in a small receiver, first green and blue, and then orange. 



Having ascertained that the crystalline solid contained no fixed base, 

 and that it yielded nothing but sulphuric acid, nitrous acid, and nitrous 

 gas, Dr Henry proceeded to ascertain the proportion of its constituents. 

 The nitrous gas was determined by collecting the gas disengaged by the 

 action of water on the solid compound, heat being applied to expel the 

 whole of it. To the residual liquid, sufficiently diluted with warm water, 

 a solution of pure barytes was added, till both the acids were complete- 

 ly neutralized. The amount of sulphate of barytes gave the exact 

 quantity of sulphuric acid. To the filtered liquid, a solution of sul- 

 phate of soda was added, and a second product of sulphate of barytes 

 subsided, from which was inferred the quantity of nitrous acid. Ab- 

 stracting the weight of these substances from the quantity subjected to 

 analysis, the remainder gave the quantity of combined water. One hun- 

 dred grains of the crystalline substance afforded 



Grain.'. 



Keal sulphuric acid, - - - 68.000 



Nitrous gas, - - 5.273 ) 



Nitrous acid, - - 7.800 / 



Water, ..... 



100.000 

 In this case, however, the results of analysis do not give direct informa- 

 tion of the nature of the original solid, because the elements of the nitrous 

 compounds are doubtless evolved in a state of arrangement very different 

 from that in which they had previously existed in the solid itself. After 

 considering the subject under various aspects, Dr Henry conceives it most 

 probable that they arc thus arranged : 



11 



