264 HISTORY OF CHEMISTRY. [LECTURE XIII. 



hydrogen atom in the hydrates is different from (i.e., less intimate 

 than) that in the substances isomeric with them. 51 



Kolbe looks on these substances as likewise belonging to the 

 group of secondary alcohols, whose existence he had foreseen, -' 

 and he tries to prove this by means of an oxidation experiment, 

 which, however, does not furnish any decisive result. Wurtz, 53 

 who also carries out this experiment, obtains acetone as well 

 as acetic acid. The question thus remained undecided 54 

 until, at a much later date (in 1878), Wischnegradzky was able 

 to prove that amylene hydrate belongs to the group of tertiary 

 alcohols. 55 These had, however, been discovered much earlier 

 (in 1863) by Butlerow 56 as the products of a very remarkable, 

 complex reaction ; but a large number of investigations by 

 Butlerow and his pupils were required in order to establish 

 conclusively the nature of these substances, and their relations 

 to the other alcohols. 



With respect to isomerism in the fatty series, Erlenmeyer 

 had obtained isobutyric ether in 1864, by the method proposed 

 by Kolbe, 57 but had not been able to discover any decided 

 difference between it and ordinary butyric ether. Morkownikoff, 

 however, established the difference later by a careful study of the 

 salts ; 58 and proved, besides, that acetonic acid is identical with 

 oxy-isobutyric acid. 59 The neat syntheses by Frankland and 

 Duppa are of consderable importance in connection with this 

 question. These chemists succeeded in passing from oxalic 

 acid to substances of the lactic acid series, and then they further 

 converted these into the corresponding members of the acrylic 

 acid series. 60 Further, by means of aceto-acetic ether, which 

 had been discovered by Geuther, 01 they were able to introduce 

 alcohol radicals into acetic acid, and thus to obtain homologues 



51 Zeitschrift fiir Chemie. 7, 419. 5 ' 2 Annalen. 132, 102. 53 Comptes 

 Rendus: 58, 971. 54 Ibid. 66, 1179. 55 Annalen. 190, 328. 



56 Repert. de Chimie pure. 5, 582 ; Bull. Soc. Chim. [2] 2, 106 ; Annalen. 

 144, I. 57 Zeitschrift fiir Chemie. 7, 642. M Annalen. 138, 361. 



59 Zeitschrift fiir Chemie. 10, 434. w Annalen. 133, 80 ; 135, 25 ; 136, 

 I ; 142, I. 61 Jahresbericht 1863, 323. 



