Decomposition of Perchloride of Mercury. 1 S 1 



evaporation yielded a crystalline deliquescent salt, composed 

 of the muriates of lime and mercury, but in what proportions 

 1 have not yet determined by experiment, though from the 

 nature of the dark-coloured salt formed, it would be easy to 

 deduce them. 



In order to examine the nature of the salt precipitated by 

 carbonate of lime, and first to ascertain whether it contained 

 any water, a portion which had been moderately dried was 

 put into a glass tube and heated in a salt-water bath. No 

 moisture was observed; the salt suffered no change of appear- 

 ance or loss of weight. It therefore contains no water of cry- 

 stallization. At higher temperatures it yields water and cor- 

 rosive sublimate, and afterwards mercury and calomel. 



The quantity of chloride of silver which the salt would 

 yield, was determined by dissolving 100 grains in acetic acid; 

 solution of nitrate of silver being added, gave a precipitate 

 which weighed 27-5 grains; and on repeating the experiment 

 28 grains were obtained, giving a mean of 27'75 of chloride of 

 silver, equivalent to 7 grains of muriatic acid. 



One hundred grains of the salt were boiled in a solution 

 of potash; the peroxide of mercury precipitated when dried 

 weighed 93-5 grains. Allowing for the errors of experiment, 

 the salt then appears to be composed of 



Muriatic acid 7* 



Peroxide of mercury 93'5 



100-5 

 If we consider this salt as a dipermuriate of mercury, it will 

 consist of 



One atom of muriatic acid 37 or 7*8 



Two atoms of peroxide of mercury... 432 or 92-2 



469 100-0 



It will be observed that the oxygen in the peroxide of mer- 

 cury amounts to 4 atoms, while the muriatic acid contains 

 only 1 atom of hydrogen; and as these are not in the propor- 

 tions required to form water, it is I think quite evident that 

 the salt in question is an anhydrous muriate, and not a chlo- 

 ride. I am confirmed in this opinion by a remark of Dr. 

 Thomson's on muriate of gold, which I have seen only since 

 I had arrived at a similar conclusion with respect to the salt 

 in question. In the Transactions of the Royal Society of Edin- 

 burgh, vol. xi. p. 28, Dr. Thomson mentions a muriate of 

 gold composed of 



Two atoms of muriatic acid 9-25 



One atom of peroxide of gold 28- 



Five atoms oi" water .^'625 



12-875 

 S 2 He 



