FROM LAVOISIER TO GAY-LUSSAC 57 



It is sufficient, therefore, to know the composition of 

 the sugar, of the alcohol and of the carbonic acid, in 

 order to prepare the balance sheet of the reaction, which 

 Lavoisier sums up in these clear terms: "The results 

 of the vinous fermentation are reduced, therefore, to 

 separating into two portions the sugar which is an oxide, 

 oxidizing one at the expense of the other to form car- 

 bonic acid, deoxidizing the other at the expense of the 

 first, to form out of it a combustible substance which 

 is the alcohol, so that, if it were possible to recombine 

 these two substances, the alcohol and the carbonic acid, 

 we should again obtain sugar." 



Here, apparently, we have reached a truly scientific 

 ground, and it seems as though, from this point on, 

 progress will be made in great strides. But this problem 

 is unlike others; everything in its course has been un- 

 certain and laborious; it even exhibits this fact, not 

 rare, but always curious, namely, that its progress has 

 been due as much to error as to truth. 



The conclusions of Lavoisier were exact but his work 

 was not. Because of the lack of good analytical methods 

 he was deceived in the composition of the sugar employed, 

 and in that of the alcohol produced. And if, in spite 

 of these errors, which should have vitiated everything, 

 he reached a conclusion correct in its general features, 

 it was due entirely to a chance compensation of errors. 

 Happy chance, one might say, providential chance, which 

 has had such enduring and useful consequences! 



Useful, for Lavoisier had apparently so clearly ex- 

 plained the mystery of fermentation, had reduced it to a 

 formula so simple, that the idea of this simplicity has 

 never left the minds of scientific men. This became 

 apparent when Gay-Lussac and Thenard, after having 

 perfected the processes of organic analysis, determined 

 the exact composition of cane-sugar. It was then very 



