CHEMISTRY AND CHIEF PRODUCTS. 483 



it was not until 1796 that the Russian chemist, Tobias Lowitz, 

 succeeded in preparing anhydrous alcohol by combining the 

 use of hygroscopic agents with fractional distillation. 



On account of its origin, alcohol which name is derived from 

 the Arabic was known as spiritus vini (spirit of wine) or spiritus 

 vitis (grape spirit). The scientific name of this fermentation 

 product is ethyl alcohol, or, according to the newer terminology, 

 methyl carbinol. The chemical formula is CH ? -CH 2 .OH, the 

 methyl group CH 3 being saturated with the carbinol CH 2 (OH), 

 or, as regarded from another point of view, the ethyl group 

 C 2 H 5 with the hydroxyl (OH). Ethyl alcohol is generally termed 

 alcohol, for short, so that when this latter name is encountered in 

 the literature, ethyl alcohol is always implied. In all other 

 cases, the special nature of the alcohol is indicated by a prefix, 

 e.g., methyl, propyl, butyl, &c. 



The manner in which alcohol is formed remained unknown 

 until J. J. Becher, in 1669, expressed the opinion that saccharine 

 liquids alone are capable of fermentation. The nature of the gas 

 liberated during the process also remained unknown for a long 

 time. It is true that B. van Helmont (1577-1644), who was a 

 chemist as well as a physician, again pointed to the fact that 

 a liberation of " gas " occurs during alcoholic fermentation. 

 Nevertheless we are unable to gather from his work, Ortus medi- 

 cince vel opera et opuscula omnia (first printed in 1648) whether 

 he was really aware of the nature of the gas in question ; and it 

 was left for MacBride, in 1764, to correlate the gas of fer- 

 mentation with the gas carbonum, or gas sylvestre as van 

 Helmont called it, and to establish its identity with carbon 

 dioxide (CO,). 



With regard to the quantitative yield of the main products of 

 fermentation, Cavendish found the amount of carbon dioxide 

 formed equal to 27 per cent, of the sugar decomposed. LAVOISIER 

 (II.) then attempted to determine the quantitative yield of both 

 products, and obtained from i cwt. of sugar 35 Ib. 5 oz. 4 dr. 19 grs. 

 of carbon dioxide and 57 Ib. n oz. 14 dr. 19 grs. of anhydrous 

 alcohol, 4 Ib. i oz. 4 dr. 3 gr. of sugar remaining undecomposed. 

 Expressed in percentages these results gave 36.8 per cent, of 

 carbon dioxide and 60. i per cent, of alcohol. The fact that these 

 values differ from those obtained at a later date is not surprising, 

 because, on the one hand, analytical methods were not so well 

 developed then as they are now, and, on the other hand, errors in 

 the recovery of the decomposition products were induced by the 

 enormous weight (i cwt.) of sugar used. It may also be men- 

 tioned that DUBRUNFAUT (IV.)> about fifty years later, employed 

 2559 kilos, of sugar in a single fermentation experiment. Under 

 such conditions it required the genius of a Lavoisier, a Gay- 

 Lussac, or a Dubrunfaut to obtain values in any way approaching 

 the truth. 



