ARSENICAL COMPOUNDS FROM ACETYL. 799 



Chloride of pteleyl, C 3 H 3 Cl (Kane). A crystalline sub- 

 stance obtained by passing a current of chlorine into mesity- 

 lene. 



SECTION VII. 

 ARSENICAL COMPOUNDS DERIVED FROM ACETYL. 



By the dry distillation of equal weights of acetate of potash 

 and arsenious acid, a remarkable liquid is obtained known as 

 the liquor of Cadet or alcarsin. This liquid may be supposed to 

 be formed by the abstraction of 2 atoms of carbonic acid from 

 the elements of 2 atoms of acetone and ] atom of arsenious 

 acid: 



2 atoms acetone. . . C 6 H 6 O 2 



1 arsenious acid. . As O 3 



2 carbonic acid. . C 2 O 4 



1 alcarsin. . . C 4 H 6 As O 



This is a body remarkable for its insupportable odour and 

 spontaneous inflammability in air. The mode of formation and 

 oxidability of alcarsin, favour the idea that it belongs to the 

 acetyl series and contains arsenietted hydrogen. In the follow- 

 ing scheme of the composition of alcarsin and its derivatives, 

 the former is represented as containing the hypothetical oxide 

 of acetyl and arsenietted hydrogen (Liebig) : 



Alcarsin. . . . Ac O -f As H 3 



Chlorarsin. . . Ac Cl 4- As H 3 



Sulpharsin. . . Ac S -f As H 3 



Cyanarsin. . . . Ac Cy + As H 3 



Alcargen. . . . Ac O 3 +As H 3 -f HO 



Berzelius, however, considering the pre- existence of arse- 

 nieted hydrogen in these compounds as improbable, presumed 

 alcarsin to be the oxide of a compound radical, which he named 

 cacodyl (from KO.KOQ and ove), in reference to the repulsive 

 odour of alcarsin. The same theory is adopted by M. Bunsen, 

 who has devoted great labour and much ingenuity to the pain- 

 ful investigation of this class of bodies, of which the sensible 

 properties are most offensive and dangerous. M. Bunsen has 



