OF ARTS AND SCIENCES. 355 



The following preliminary notice of a memoir was pre- 

 sented : — 



On the Double Salts of Cyanide of Mercury, by William P. 



Dexter. 



An investigation of some of the compounds of cyanide of mer- 

 cury having ah'eady occupied me for a considerable time, I would 

 beg leave to communicate the conchisions at which I have thus far 

 arrived ; and would state that I am still engaged in the prosecution 

 of this subject. 



For several of these compounds my analyses have led me to infer a 

 composition differing from that assigned to them by previous investiga- 

 tors. For example, the salts of cyanide of mercury with the chlo- 

 rides of nickel and cobalt, to which Poggiale * gives the formulae 



NiCl, HgCy, 6 HO, 

 2 CoCl, HgCy, 4 HO, 



I have found to be expressed by 



NiCl, 2 HgCy, 7 HO, 

 CoCl, 2 HgCy, 7 HO, 



thus removing a difference which was certainly not to be expected in 

 bodies so nearly related, and showing their conformity in constitution 

 with the other salts of this class. 



The salt to which Desfosses f gives the formula 



KCl, 2 HgCy, HO, 



I find to contain two equivalents of water ; and for the analogous salt 

 with chloride of barium, which, according to Poggiale, contains but 

 4 HO, I get the formula 



BaCl, 2 HgCy, 6 HO ; 



it then agrees in composition with the corresponding salts of strontium 

 and calcium. 



The cyanide unites also with chlorides of the type R2 CI3 ; I have 



* Compt. Rend., XXIIL 762. 



t Gmelin, Handb. d. Org. Ch. Bd. I., S. 417. The original memoir in Journ. 

 Chim. Me'd., VI. 261, is not accessible to me. 



