on some Hydrar gyro- Cyanurets. 363 



distilled water; it was then evaporated to dryness in a 

 weighed platinum capsule, ignited and weighed O86 grs. 

 = 0*59 of cyanuret of magnesium = 1 equivalent. 



10 grs. (in crystals) of the salt were dissolved in distilled 

 water, to which a solution of sulphuret of magnesium was 

 added ; the bi-sulphuret of mercury thus obtained, after 

 being well washed on a weighed filter, and dried, weighed 

 8*5 grs. = 9'27 of bi-cyanuret of mercury = 2 equivalents. 



To the solution filtered from the precipitated bi-sulphuret 

 of mercury (which consisted only of cyanuret of magnesium), 

 a solution of nitrate of silver was added, which precipitated 

 the cyanogen as cyanuret of silver, which was converted into 

 chloride by acting on it with muriatic acid ; the chloride of 

 silver, after being completely dried, weighed 10*70 grs. = 

 1'97 of cyanogen = 5 equivalents; 10 grs., therefore, of 

 this salt (in crystals) contain, 



Of Water of crystallization, 0*14 = 1 equivalent. 

 ,, Cyanuret of magnesium, 0*59 = 1 equivalent. 

 ,, Bi-cyanuret of mercury, 9*27 = 2 equivalents. 



10-00 



The equivalent of this salt (in crystals) is 557'65 ; its 

 composition may be expressed in symbols thus, 2 (Hg + 

 Cy 2 ) + (Mg + Cy) + (Aq.) _ 



The simple cyanurets used in forming the above salts 

 were formed by adding a solution of bi-cyanuret of mercury 

 to the corresponding sulphur ets, when the bi-cyanuret of 

 mercury exchanged its cyanogen for the sulphur of the sul- 

 phurets, and was precipitated as bi-sulphuret of mercury ; the 

 only simple cyanuret that was not made in this manner, was 

 the cyanuret of barium, which was made by heating the 

 ferro-cyanuret to decomposition and dissolving out the 

 cyanuret of barium with distilled water. 



The solutions of these salts have no odour, but a dis- 

 agreeable metallic taste ; they are not in the least decomposed 

 by exposure to the air ; mercury can be detected in them all 

 by sidphuretted hydrogen ; a solution of nitrate of silver 

 causes a white precipitate, which, I think, is most likely 

 not cyanuret of silver, but a compound of bi-cyanuret of 

 mercury and cyanuret of silver ; on account of this, in ana- 

 lyzing the salts, they were converted into simple cyanurets 



