BUNSEN ON THE CACODYL SERIES. 287 
The alcarsin prepared from the first portion of the distillation 
afforded the following results :— 
I. 0°548 grm. substance yielded 0°2688 grm. water, and 0°4532 
carbonic acid. 
That prepared from the second portion furnished— 
II. 0°5974 grm. substance 0°:2915 grm. water, and 0°49 car- 
bonic acid. 
The experiments correspond with 
I. rT. Calculated. 
Carbon . . 22°86 22°68 C, 21°52 
Hydrogen . 5°44 5°42 H, 5:27 
These members, compared with those given in my first me- 
moir on this subject, appear to lie between them. This result, as 
well as the other, cannot be reconciled with the opinion that 
there is oxygen present, nor with the contrary one. In the first 
case the proportion of carbon and hydrogen is too high, and in 
the last too low. It results therefore from the accordance be- 
tween the different analyses, that the constant slight variation 
depends most probably more on the impurity of the substance 
than on an error in the analysis. This opinion is strengthened 
by the fact, that the substance analysed above, when heated with 
muriatic acid, yielded, besides the chloride of cacodyl, a brick- 
red powder, insoluble in everything, and which appears also to 
be formed when alcarsin is conducted through heated tubes; I 
have therefore executed the distillation of the crude fluid of Cadet 
under a layer of water freed from atmospheric air by boiling, 
which not only prevented all access of air, but also dissolved 
any of the oxidized substances that might happen to be formed, 
and effectually prevented the temperature rising so high as to 
cause any decomposition. In this way I obtained alcarsin 
in a state of perfect purity, as the following experiments will 
show :— 
I. 0°4711 grm. substance gave 0°2235 erm. of water, and 
0°3708 grm. carbonic acid. 
II. 0°5164 grm. substance gave 0°2485 grm. of water, and 
0°4045 grm. carbonic acid. 
0°5258 grm. substance, when burnt with oxide of nickel, 
yielded 0°7142 grm. sulphuret of arsenic. 
0°711 grm. of the above, treated with nitric acid, yielded 
0°2131 grm. melted sulphur, and 1:2332 grm. sulphate of ba- 
rytes. 
