BUNSEN ON THE CACODYL SERIES. 307 
those cases in which it is expressed with so much clearness, and 
which have been so full of promise in the development of organic 
chemistry. 
The following results will bear out these observations :— 
10. Compound of Chloride of Mercury with Oxide of 
Cacodyl. 
This compound is formed by the action of sublimate on the 
oxide of cacodyl. A voluminous white precipitate is formed on 
mixing together a weak alcoholic solution of the latter with a 
weak solution of sublimate. It consists of a mixture of the oxide 
and chloride. The penetrating odour of the liquid entirely dis- 
appears. It may be rendered quite pure by pressure between 
the folds of blotting-paper, dissolving again in boiling water 
and three or four crystallizations. The preparation is even more 
easy by employing the liquid obtained by the slow oxidation of 
oxide of cacody] in the air, and which is easily soluble in alcohol. 
It is necessary in both cases not to add an excess of the chlo- 
ride, as the new compound is immediately decomposed by sub- 
limate. It sometimes happens that nothing but protochloride 
of mercury is obtained by neglecting this precaution. All the 
compounds of cacodyl corresponding to the oxide are equally 
applicable in the preparation of this substance. The combus- 
tion of this substance is best conducted with oxide of copper 
in a long tube which contains chromate of lead in one end. As 
it is impossible to prevent a small quantity of chloride of mer- 
cury passing over into the chloride of calcium tube, it is neces- 
sary to blow two small bulbs on the long end of this tube, so that 
the chloride may be deposited in them before it arrives at the 
chloride of calcium. In the experiments made it was found to 
be wholly deposited in the first bulb, and its weight was very 
easily ascertained by cutting off this bulb after the combustion, 
&e. was finished, drying it to expel any moisture, and then 
weighing. The substance analysed was prepared from pure 
cyanide of cacodyl, three times crystallized, and dried at the or- 
dinary temperature over sulphuric acid in vacuo. 
1. Substance employed in analysis . . . 2°162 grm. 
Water and chloride of mercury . . . 0°4235 ... 
Chloride of mercury . . . . . . - 0°0805 ... 
erIsGnIC ded. | ate tee) 2)...” 04870... 
