Progress of Foreign Science. 4(>l 



On u new Compound formed by mixing together a solution of Cya- 

 nide of Mercury with a solution of Iodide of Potassium by M. Calliot. 

 — In trying to detect the presence of cyanide of mercury, by 

 the iodide of potassium, he was much surprised to see form in 

 the liquid a multitude of white pearly crystals, instead of 

 a precipitate of deutiodide of mercury, as he expected. After 

 having washed these crystals, he dissolved them in water, and 

 ro-crystallized the solution. He obtained large plates, thin and 

 brilliant, imalterable in the air, inodorous in the dry state, but 

 having a smell like that of bitter almonds when in solution ; so- 

 luble in sixteen times their weight of water, at the ordinary 

 temperature, but requiring much less hot water for their solution. 

 They are also soluble in about ninety-six parts of alcohol at 

 34° (0.847.). 



This new compound, at a temperature incapable of destroying 

 it, loses nothing of its weight, or its lustre. It is of conse- 

 quence, probably anhydrous. When more strongly heated, it is 

 decomposed, and gives for products, cyanogen, mercury, and a 

 greenish yellow vapour, mingled with protiodide of mercury. 

 The iodide of potassium which remains fixed is blackened by a 

 little finely-divided charcoal. Put successively in contact with 

 the strongest and the weakest acids, such as the benzoic, cam- 

 phoric and arsenious, it is converted into deutiodide of mercury, 

 and hydrocyanic acid is disengaged. This acid itself, and 

 carbonic acid, produce no effect on the compound. By 

 sulphuretted hydrogen, black sulphuret of mercury is thrown 

 down, and hydrocyanic acid is disengaged. 



The hydro-sulphurets produce on the solution of this body, a 

 black precipitate ; the salts of lead, a yellow precipitate of 

 iodide of lead, and the salts of deutoxide of mercury, a red pre- 

 cipitate of deutiodide of mercury. Chlorine and the bi-chloride 

 of mercury determine in it a red precipitate soluble in an excess 

 of the solution. Iodine dissolves in it, insomuch the greater 

 quantity, as its solution is the more concentrated. Potash, so- 

 da, and ammonia, whether free or combined with an acid, pro- 

 duce no decomposition of it. 



M. Caillot had regarded this compound as formed of one 

 proportion of cyanide of mercury, and one proportion of iodide 

 of potassium ; but having added sulphuric acid in slight excess 

 to the solution, he found in the liquid, resting over the abun- 

 dant precipitate of deutoxide of mercury which took place, a 

 small quantity of cyanide of mercury. It remains, therefore, to 

 make the analysis of it, in order to learn its composition. He 

 concludes, by stating that 24 parts treated by hydrosulphuret of 

 soda, afforded nearly 13 of sulphuret of mercury. — Ann. de Ch. 

 et de Vhys. xix. p. 220. 



