7i 
of chlorine and carbon , &c. 
acid gas and 1 volume of carbonic oxide ; and that at the 
intense temperature produced within the tube by the 
inflammation, the rest of the oxygen and the mercury 
had decomposed a farther portion of the substance, giving 
rise to the second volume of the carbonic oxide, and to the 
calomel. 
A mixture of 2 volumes of hydrogen and 1 volume of 
oxygen was made, and 3 volumes of it detonated with the 
vapour, as before. After cooling, the expansion was to 6 vo- 
lumes ; 4 of which were muriatic acid, and 2 carbonic oxide. 
There was no action on the mercury in this experiment. 
Again, 5 volumes of the same mixture being detonated with 
the vapour of the substance, expanded to 9.75 volumes, of 
which 6 25 were absorbed by water and were muriatic acid, 
and 3.5 were carbonic oxide mixed with a very small portion 
of air introduced along with the fluid chloride. These ex- 
periments, I think, establish the composition of the proto- 
chloride of carbon, and prove that it contains 1 proportion of 
each of its elements. 
From a consideration of the proportions of these two chlo- 
rides of carbon, it seems extremely probable that another 
may exist, composed of 2 proportions of chlorine combined 
with 1 of carbon. I have searched assiduously for such a 
compound, but am undecided respecting its production. When 
the fluid proto-chloride was exposed with chlorine to solar 
light, crystals were formed, as before described. The greater 
number of these were certainly the perchloride first mentioned 
in this paper ; but when the retort was examined by a micro- 
scope, some rhomboidal crystals were observed here and 
there among those of the usual dendritic and square forms. 
