BUNSEN ON THE CACODYL SERIES. 311 
3 Kd Cl 
Kd O 
4 (Kd O + Hg, Cl,)=4 3 Hg, Cl 
Hg, Cl 
If the formation of oxide of cacody] with chloride of mercury 
does not now present any difficulties, it must however appear 
most extraordinary, when we perceive the oxide of cacodyl re- 
main unchanged in contact with one of the most powerful oxid- 
izing agents we possess, and much more when we call to mind 
the strong affinity of the oxide for oxygen, which rises to such 
intensity in oxygen gas, that it becomes heated till it inflames. 
This fact would indeed be unfavourable to the view taken above 
with respect to the amount of oxygen, did not the formation of 
this substance, on the other hand, from a liquid obtained by di- 
rect oxidation of the oxide of cacodyl in the air, lead to another 
explanation which meets the difficulty. 
The substance on which the formation of the mercurial com- 
pound depends in this mixture of oxidized products, is a liquid 
which nearly corresponds with alcarsin in its composition, but 
widely differs from that body in its characters, for it neither 
smokes in contact with the air nor inflames, and undergoes 
oxidation very slowly. 
The experiments which I have hitherto made on this sub- 
stance, do not decide whether it is a compound isomeric with 
oxide of cacodyl, or a higher degree of oxidation, answering to 
the formula Kd, O,. If the first supposition be true, we see 
that the formation of the mercurial compound arises from the 
difficulty of the oxidation of this modification. But should the 
latter view, on the contrary, prove correct, and the mercurial 
compound contain the higher degree of oxidation instead of the 
lower, not only would its formation agree with one of the most 
common reactions, but its relation to oxidizing and reducing 
agents, as well as to the hydrogen acids, would be capable of the 
most natural solution. In this way, this higher degree of oxida- 
tion would be decomposed by the action of the hydrogen acids 
into oxide of cacodyl and cacodylic acid, in precisely the same 
way as the inorganic peroxides, and the former would after- 
wards further undergo its own peculiar decompositions. I hope 
shortly to be able, from some experiments now in progress, to 
decide this question, and shall return to the subject in the second 
