xvn MOLECULAR ARCHITECTURE 387 



carbon and of hydrogen brought to the state of acid by the 

 addition of oxygen. This acid is, consequently, composed 

 of the same principles as tartaric acid, malic acid, etc. but 

 the proportion of the principles is different for each of 

 these acids, and it would seem that acetic acid is the most 

 oxygenated of all " ( Works, I. 218). 



Alcohol and ether. It would be difficult to exaggerate 

 the importance to organic chemistry of the process of vinous 

 fermentation. Fermented liquors have been known from 

 time immemorial. The spirit or " aqua vitse " prepared 

 from them by distillation was known in the time of Geber. 

 A minute description of the methods of purifying it is given 

 by Raymond Lully (1235-1315). The spirit, prepared 

 from dark wine, was subjected to repeated fractional distil- 

 lation ; in the first distillation only one-tenth of the distillate 

 was collected, then one-fourth, one-third, one-half, and 

 finally (in 14 further distillations) almost the whole of the 

 volatile distillate. The spirit was also dried by distilling 

 from calcined tartar (dry potassium carbonate). There 

 can be little doubt that by such methods Lully would 

 obtain almost pure ALCOHOL. Lully also tried the action of 

 oil of vitriol on alcohol, and was one of the first to convert 

 it into the still more volatile ETHER. The further action of 

 oil of vitriol on alcohol, whereby it is converted into a gas, 

 OLEFIANT GAS or ETHYLENE, was referred to by Becher in 

 1669 andhas already been described in detail (pp. 154-156). 



In view of its unique importance, it is not surprising that 

 alcohol was selected by Lavoisier as the subject of his first 

 organic' analysis (pp. 146-148). Both alcohol and ether 

 were analysed by de Saussure in 1807 (Ann. de Chimie, 

 1807, 62, 225-241), by a variety of methods, but with 

 no great measure of success; in 1814, however (Ann. de 

 Chimie, 1814, 89, 273-305), he obtained a very good 

 analysis of alcohol, by first decomposing it in a red-hot 

 tube, and a less accurate analysis of ether, by exploding 



c c 2 



