6 4 Mr. Faraday on two new compounds 
of the chloride would give 10 of carbon nearly, but by cal- 
culation 100 should give 10.19. The difference is so small, 
as to come within the limits of errors in experiment. 
5 grains were passed over peroxide of copper in a tube 
made of green phial glass, and the chlorine estimated in the 
same manner as before. 17.7 grains of chloride of silver 
were obtained equal to 4.36 grains of chlorine. This result 
approaches much nearer to the calculated result than the 
former ; but there had still been action on the tube, and a 
minute portion of the substance had passed undecomposed, 
and condensed at the opposite end of the tube in crystals. 
Experiments made by passing the perchloride over hot 
lime or barytes, promise to be more accurate and easy of 
performance. In the mean time, the above analytical results 
will perhaps be considered as strong corroboration of the 
opinion of the nature of the compound, deduced from the 
synthetical experiments ; and the composition of the per- 
chloride of carbon will be 
3 proportions of chlorine =2= 100.5 
2 ditto carbon = 11.4 
111.9 
Proto-chloride of carbon. 
Having said so much on the nature of the perchloride of 
carbon, I shall have less occasion to dwell on the proofs that 
the compound I am about to describe, is also a binary combi- 
nation of carbon and chlorine. 
When the vapour of the perchloride of carbon is heated to 
dull redness, chlorine is liberated, and a new compound of 
that element and carbon is produced. This is readily shown 
