A SOURCE OF ANIMAL HEAT. 89 



According to the ordinary view, 12 equivalents of 

 carbonic acid separate from 3 of sugar, yielding 6 of 

 alcohol, that is, exactly the same amount of these pro- 

 ducts as if two thirds of the sugar had yielded oxygen 

 to the remaining third, so as completely to oxidize its 

 elements. 



C 36 H 36 36 = C 24 H 36 12 + 12C0 2 . 



By a comparison of these two methods of represent- 

 ing the same change, it will easily be seen, that the 

 division or splitting of a compound like sugar into car- 

 bonic acid, on the one hand, and a compound containing 

 little oxygen, on the other, is, in its results, perfectly 

 equivalent to a separation of oxygen from a certain por- 

 tion of the compound and the oxidation or combustion 

 of another portion of it at the expense of this oxygen. 



It is well known that the temperature of a fermenting 

 liquid rises ; and if we assume that a hogshead of wort, 

 holding 1,200 litres =2,400 Ibs., French weight, con- 

 tains 16 per cent, of sugar, in all 384 Ibs., then, during 

 the fermentation of this sugar, an amount of heat must 

 be generated equal to that which would be produced 

 by the combustion of 51 Ibs. of carbon. 



This is equal to a quantity of heat, by which every 

 pound of the liquid might be heated by 297-9 ; that is, 

 supposing the decomposition of the sugar to occur in a 

 period of time too short to be measured. This is well 

 known not to be the case ; the fermentation lasts five or 

 six days, and each pound of liquid receives the 297-9 



* For an explanation of the formulae and equations employed, see 

 the Introduction to the Appendix. 



