110 Mr. A. S. Couper on a Neiv Chemical Theory. 



H 01 CI 



C^H C^^oi-^C^cl 

 H 0/ Cl 



Here the whole four of hydrogen are not bound by a mutual 

 affinity ; for each element of hydrogen can be substituted for one 

 of chlorine in regular series, beginning with the first and ending 

 with the last. The atoms of oxygen ai-e, on the contrary, united 

 in pairs (which will be more fully developed hereafter), andcmly 

 for two atoms of oxygen two of chlorine can be substituted ; 

 thus — 01 



1} 



In the same manner with bodies that contain multiples of C'^ 

 united to hydrogen, &c. 



Take the inverse of this. If the four atoms of hydrogen were 

 bound together, we could evidently expect to form such bodies as 



H" 



or for bodies like C^ H^, C« H«, C^ H^, one would naturally 

 expect to find the carbon substituted for chlorine, and find bodies 



likeH-'^r, H«C16, H8Cl«&c. 



These bodies are not only unknown, but the whole history of 

 hydrogen might be investigated and not a single instance be 

 found to favour the opinion that it has any affinity for itself 

 when in union with another element. 



Now, on the other hand, carbon remains chemically united to 

 carbon, while perhaps 8 equivalents of hydi'ogen are exchanged 

 for 8 equivalents of chlorine, as in naphthaline. Analogous to 



this is the conversion of alcohol, C'*tt5 , and the hydrocar- 



bide C^ H^ into C"* Cl^". All the countless instances of substitu- 

 tion of chlorine, &c. tend in the same direction. They prove 

 beyond doubt that carbon enters into chemical union with carbon, 

 and that in the most stable manner. This affinity, one of the 

 strongest that carbon displays, is perhaps only inferior to that 

 which it possesses for oxygen. 



Another feature in the affinity of carbon is, that it combines 

 by degrees of two ; thus, C^ 0^ and C^ O^ C H^ and C H^, 



