316 BUNSEN ON THE CACODYL SERIES. 
I. 0°915 grm. of substance yielded 0°292 grm. water, and 0°475 
grm. carbonic acid. 
II. 0:999 grm. of substance yielded 0°3305 grm. water, and 
0°5375 grm. carbonic acid. 
0:636 grm. bromide of silver, and 0:026 grm. of silver on the 
filter, were obtained by dissolving 0°8265 grm. of this substance 
in alcohol, precipitating by nitrate of silver, and heating with a 
little nitric acid. 
0°631 grm. sulphuret of arsenic was obtained by oxidizing 
0°5988 grm. with oxide of zinc, dissolving the same in nitric acid, 
and removing the nitric acid by means of the sulphuric. 0°590 
erm. of this sulphuret, after oxidation, yielded 0°8882 grm. sul- 
phate of barytes, and 0°2148 grm. sulphur. 
These experiments give the following numbers :— 
I. Il. Calculated. 
Carbon .. C, 14°35 14°84 14°70 
Hydrogen. H, 3°55 3°67 3°60 
Arsenic .. As, 45°15 ae 45°21 
Bromine. . Brs 34°60 ate 35°29 
Oxygen .. O; 2°35 ies 1:20 
100°00 100°00 
Whence it follows that this substance is represented by a for- 
mula exactly corresponding to that of the basic chloride, viz. 
(C,H, As, + O) + 3(C,H, As, + Br) = KdO+3Kd Br. 
14, Basic Iodide of Cacodyl. 
This basic iodide is formed at the same time as the iodide, on 
distilling the oxide of cacodyl and hydriodic acid. It is de- 
posited from the neutral compound in the form of yellow ecry- 
stalline crusts. It may be nearly freed from the fluid iodide by 
pressing these crusts between folds of blotting-paper under water 
containing no atmospheric air. It must then be dissolved in 
absolute alcohol, from which it can be obtained in fine large 
crystals by cooling the solution. The alcohol which is retained 
by the crystals can be removed by pressure in blotting-paper 
under water. By allowing it to remain in contact with chloride 
of calcium in a fluid state for some days, it is freed from the 
water, and must lastly be distilled in the distillation tube till 
about half has passed over. It is impossible to obtain this sub- 
stance free from some oxide, as it possesses as great an affinity 
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