1820.] of Chlorine and Carbon, $c. 51 



portion of the substance, giving rise to the second volume of 

 the carbonic oxide, and to the calomel. 



A mixture of two volumes of hydrogen and one volume of 

 oxygen was made, and three volumes of it detonated with the 

 vapour, as before. After cooling, the expansion was to six 

 volumes, four of which were muriatic acid, and two carbonic 

 oxide. There was no action on the mercury in this experiment. 

 Again, five 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 experiments, 

 I think, establish the composition of the protochloride of car- 

 bon, and prove that it contains one proportion of each of its 

 elements. 



From a consideration of the proportions of these two chlorides 

 of carbon, it seems extremely probable that another may exist, 

 composed of two proportions of chlorine combined with one of 

 carbon. I have searched assiduously for such a compound, 

 but am undecided respecting its production. When the fluid 

 protochloride 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 microscope, 

 some rhomboidal crystals were observed here and there among 

 those of the usual dendritic and square forms. These may 

 perhaps be the real perchloride ; but I had not time, before the 

 season of bright sunshine passed away, to examine minutely 

 what happens in these circumstances ; and must defer this, with 

 many other points, till the next year brings more favourable 

 weather. 



Compound of Iodine, Carbon, and Hydrogen. The analogy 

 which exists between chlorine and iodine, naturally suggested 

 the possible existence of an iodide of carbon, and the means 

 which had succeeded with the one element offered the best 

 promise of success with the other. 



Iodine and olefiant gas were put in various proportions into 

 retorts, and exposed to the sun's rays. After awhile, colour- 

 less crystals formed in the vessels, and a partial vacuum was 

 produced. The gas in the vessels being then examined, was 



