LECTURE XIV.] HISTORY OF CHEMISTRY. 283 



carbons with high molecular weights, which are not so fully 

 examined as yet (such as pyrene, picene, etc.), may be derived 

 from benzene in an analogous manner. 



Some other investigations in which a relationship can be 

 recognised between certain compounds containing nitrogen 

 especially the alkaloids and benzene, appear to be probably 

 still more important than the foregoing. This branch of the 

 subject, only opened up a few years ago, already presents so 

 many remarkable results that it cannot be omitted here. 



The analogy of the formulae of benzene, C H , and naph- 

 thalene, C 10 H 8 , on the one hand, with those of pyridine, 

 C 5 H f) N, and quinoline, C 9 H 7 N, on the other, admitted of the 

 hypothesis that the latter compounds might be derived from 

 the former by the replacement in each of a CH group by N. 

 and consequently the following formulae were advanced for 

 pyridine and quinoline. 



CH N 

 Pyridine. Quinoline. 



This view was made known by means of private communi- 

 cations by Korner, and is usually known as Korner's hypothesis. 

 It was first published by Dewar/" s 



A large number of facts can now be adduced in support of 

 the view, and the more important of these may be mentioned 

 here. 



Anderson, the discoverer of pyridine, had already found in 

 animal oil, besides pyridine, a number of homologous bases. 59 

 The further examination of bone tar has yielded, as yet, only 

 methyl pyridines, 00 just as methyl benzenes only are contained 



58 Chem. News. 23, 38; Zeitschrift fiir Chemie. 14, 117. r>9 Ann- 

 alen. 60, 86 ; 70, 32 ; 75, 80 ; 80, 44 ; 94, 358 ; see also Unverdorben, 

 Pogg. Ann. II, 59. 60 Weidel, Berichte. 12, 1989; Ladenburg and 

 Roth, ibid. 18, 47 and 913. 



