Dr. Kane on the Compounds of Ammonia. 13 



examined by Mltscherllch and Soubeiran, with results, however, so discrepant, as 

 not to allow us to draw any conclusion whatsoever from them. 



Almost immediately on commencing the examination of this reaction, I 

 found that the nature of the precipitate obtained was liable to considerable 

 variation, and that very trivial alterations in the conditions, under which the 

 ammonia was added, changed the proportion of quicksilver by four or five in the 

 hundred, — limits including the values obtained by the above-mentioned chemists. 

 It therefore became probable that, as in the case of white precipitate, the existence 

 of two or more different bodies had led to the discrepancies in the statements of 

 those chemists ; and by paying minute attention to the circumstances which influ- 

 ence their formation, I was led to detect the existence of three distinct ammo- 

 niacal subnitrates, as prepared by mere precipitation. The circumstances which 

 influence the nature of the precipitate are, the concentration of the mercurial 

 solution, its degree of acidity, the strength of the water of ammonia, the excess 

 of one or other reagent, and the temperature. By slight changes of these, there 

 are produced modifications of composition, and frequently an imperfect change 

 from one to the other form takes place. In addition to these three precipitated 

 compounds, there are two others obtained by crystallization, of which one had 

 been examined by the younger Mitscherlich, and the other was met with first in 

 the course of these investigations. 



Ammonia Sub-pernitrate, No. 1. — When a dilute, and not very acid solution 

 of pernitrate of mercury is treated by weak water of ammonia, (taking care not to 

 add an excess of the latter, and the solution being cold,) there is obtained a pure 

 milk-white precipitate, not granular, which remains suspended for a considerable 

 time. This precipitate, collected on a filter, may be exposed to a heat of boiling 

 water without change, and is consequently easily dried. 



When this powder is heated, it becomes yellow, and gives azote, ammonia, 

 then red fumes, and finally oxygen and quicksilver. If boiled with water, it 

 becomes granular and heavier, deposits itself more easily, and has lost, in some 

 degree, its pure white colour. The water remains neutral, but is found to hold 

 some nitrate of ammonia in solution. 



On analysis, this powder yielded precisely the same results as had been 

 obtained by the younger Mitscherlich ; on that account I shall not insert the 



