LECTURE XII.] HISTORY OF CHEMISTRY. 237 



O. 2 H by H and of O, by H, HO,H 3 C 2 ,O Methyl alcohol, 

 2 H C,,H 3 O, H, HO, C H 2 }C 2 ,0 Ethyl alcohol. 



On the conversion of the alcohols into the corresponding 

 acids, the two hydrogen atoms are replaced again by oxygen 

 equivalents. Kolbe's view is now more definite than William- 

 son's. Whereas the latter assumes the conversion of the radical 



C.,H 5 into C 9 H 3 O [C=i2], according to Kolbe, C r 2 rj is 



" ^2"3 



H 



produced from C, { H . The difference is important, and 



- [C.H, 



it leads Kolbe to foresee the existence of a new class of 

 alcohols, which he announces as follows : 53 



" If the undernoted formulae, by means of which I pre- 

 viously represented the rational composition of acetic acid, and 

 of the corresponding aldehyde and alcohol, are inspected - 

 HO. (C 2 H 8 ) [C,OJ O Acetic acid, 

 J Aldehyde, 



HO.| C ^ 3 | C 2 ,O Alcohol, 



it will be understood, at the first glance, how it comes that of 

 the five hydrogen atoms in the ethyl oxide of the alcohol, only 

 two are substituted in the oxidation of the latter and only one 

 in that of aldehyde. It is those atoms of hydrogen in alcohol 

 and in aldehyde which stand by themselves that are subject to 

 the oxidising influences, and that present themselves to the 

 oxygen as points of attack far more easily accessible than the 

 other hydrogen atoms which are more firmly held in the 

 methyl radical. 



" The above conceptions of the chemical constitution of 

 the alcohols reveal to us the prospect of the discovery of new 

 alcohols as yet unknown, as well as of a new class of substances 

 which, while closely related to the alcohols in respect to their 

 composition, will also probably share many properties with 



5:1 Annalen. 113, 305-306. 



