26 Dr. Kane on the Compounds of Ammonia. 



now appears to have tacitly abandoned this opinion, and properly, for there is no 

 doubt but that this white powder is a compound of red oxide, and is one or other 

 of the bodies which have been already described in this paper. When treated with 

 iodide of potassium it gives a reddish yellow powder, and it dissolves gently in 

 muriatic acid, without the disengagement of any red fumes indicating a transition 

 to a higher degree of oxydation. At the same time that this white per- 

 compound is formed there is always some metallic mercury set free, which can 

 generally be recognized in the grey specimens by using a lens, but the quantity 

 is seldom so large as to allow of its mechanical separation by the application of 

 pressure only. 



From all these circumstances it is evident, that the specimens of Hannehman's 

 soluble mercury, which are of the finest black in colour, are generated under the 

 circumstances most favourable to their perfect purity. And as all the chances of 

 error, except that of analysis, tend to increase the value of mercury, it results, 

 that where the error of manipulation affects all equally, the lowest estimate 

 should be that nearest to the truth. Hence I feel justified in assuming, with 

 some confidence, that the numbers 82.27 and 82.39 are those by which the true 

 formula may be established, and we must therefore consider Hannehman's solu- 

 ble mercury to be the ammonia sub-nitrate, 



NHg.NOj-f 2h^o, 



which should give 82.29 mercury per cent., and evidently corresponds to the 

 yellow subnitrate formed by water, which has been proved to be 



HO.NOj-t- 2Hg-o. 



Note It has been very gratifying to me to find that Ullgren, who undertook, under the direc- 

 tion of Berzehus, to control the analyses contained in my first memoir on the Ammonia Compounds, 

 has verified, even to the most minute point, all the results which I then brought forward. I did not 

 receive the Jahresbericht for 1837, containing Berzelius's observations, until this first part of the 

 present memoir had been partly printed, and hence could not earlier introduce any note of the sug- 

 gestions which he makes. In Germany or Sweden it will not be necessary to adopt the word 

 amidogene, as the word amide harmonizes better with chlor. cyan. iod. and others ; but in English 

 and French it is preferable that there should be a termination, as in cyanogene and oxygene, the 

 final ide being in these languanges restricted to binary compounds. I shall, however, for the future 

 adopt his terms of amidides and amidurets, as I consider them still more expressive of the nature of 

 the bodies, and more directly formed from amidogene than the word amides. 



