Double Salts ofMoxury, ^37 



ammonium, the quantity of the latter by calculation being 



1*74 grains. 

 The results of experiment and calculation will therefore 



give Experiment. Calculation. 



Bicyanide of mercury 7*94? 8'(26 



Chloride of ammonium ... 1*68 1'74< 



Loss '38 



10-00 10-00 



These results sufficiently approximate to warrant us in 

 concluding that the atomic representation of the salt would 

 be as follows : 



Bicyanide of mercury 255-72 = 1 atom. 



Chloride of ammonium 53*65 = 1 atom. 



309-37 atomic weight of 

 double salt. 



2 4 



Its symbol will therefore be (Hg Cy + N H CI). 

 I have adopted the term chloride of ammonium instead of 

 that of muriate of ammonia, because the idea of the chlorine 



4 



in this case being united with a metal (ammonium) (N H) is 

 strictly in accordance with what actually exists in all other 

 haloid salts, as also in those combinations of haloid salts which 

 constitute the double salts under consideration: besides, as 

 chloride of ammonium is isomorphous with the chlorides, 

 iodides, and bromides of potassium and sodium, and as the 

 ammoniacal double salt is isomorphous with the other double 

 salts into which the metals of the fixed alkalis and earths enter 

 as ingredients, so it is in the highest degree probable that the 

 atom of hydrogen in the ammoniacal salt which exists over 

 and above what is sufficient to form ammonia with the nitro- 

 gen, is not united to the chlorine as hydrochloric acid, but to 

 the ammonia to form the metal ammonium. 



The Chloro-cyanide of Sodium and Mercury, 



This salt may be obtained by dissolving in water 15 parts 

 by weight of chloride of sodium and 60 parts of bicyanide of 

 mercury, evaporating and crystallizing. It crystallizes also in 

 flattened quadrangular prisms of a somewhat silky lustre, is 

 soluble in weak alcohol, from which it readily crystallizes. 



Ten grains of the dried salt were dissolved in water and 

 precipitated by sulphuretted hydrogen: the washed and dried 

 bisulphuret of mercury weighed 7*30 grs. = 7-94< grs. of bi- 

 cyanide ; the calculated proportions are 7-4<753 bisulphuret 

 = 8-13 bicyanide of mercury. The aqueous solution freed 



