40 



Of theprecipi- 

 tate one part 

 withfiveof fugar 

 fermented readi- 



Produas of 

 carbonic acid 

 and fpirit ob- 

 tained. 



equal to 171.5 

 oi alcohol. 



The refiduum 

 12 grammes, 

 jiaufeous and, 

 (lightly acid. 

 Lavoifier fays 

 the acid is the 

 acetous. 

 Refidue of the 

 ferment* 



VINOUS FERMENTATION. 



the phllbfopher; to both by its produ6ls, and to the latter be- 

 caufeit may be a fertile fource of refleftlon and of new truths. 

 It is much to be regretted, that Lavoifier did not purfue the 

 inveftigation as he intended, and examine it with that care, 

 which is confpicuous in all his labours. Who was more capa- 

 ble of giving birth to a theory of fermentation, than the author 

 of the modern theory of chemiftry ? No doubt he was prevented 

 from doing this by a concurrence of circumftances : and this 

 theory, important as it is to fcience, has hitherto remained 

 vague and hypothetical. Knowing the fermentative princi- 

 ple, it could not avoid naturally making a part of my refearches: 

 if I have not rendered it as clear as I hoped, at lead the veil 

 with which it was covered is removed, and it refls on reafon- 

 ing confirmed by experiment. 



To obtain the folution of this problem, I added together 

 different quantities of ferment and fugar ; I obferved in every 

 cafe what became of both; and I confirmed by farther obfer- 

 vations what the preceding had fuggefted. Sixty grammes 

 (927grains or nearly one ounce of ferment) not dried, and three 

 hundred grammes (4630 grains) of fugar entered into fermen- 

 tation readily, the temperature being 15^ (centigrade=;59^ 

 Farenheit.) In four or five days all the faccharine matter had 

 difappeared; 51.5 litres (304-1 cubic inches) of carbonic acid 

 had been evolved; the liquor being filtered, and diftilled to 

 two thirds, gave on afecond reflification 863 grammes of fpirit 

 at 13°. The apparatus was fo contrived, that nothing was 

 loft: the receivers were cobled with common fait and ice. I 

 found by fynthefis, that this quantity of fpirit was equivalent 

 to 171.5 grammes of alcohol at 39°. The refidues left after 

 diftilling the fpirit were poured into diflies and evaporated to 

 drynefs; from the refiduum of the fecond diftillation nothing 

 was obtained, but that of the firfl yielded about 12 grammes 

 of a naufeous fubftance, flightly acid, and feebly attracting 

 the moiflure of the air. I wiihed to difcover the nature of 

 this acid, but there was too little to afcertain it. Lavoifier 

 fays, it is the acetous. Laftly, of the fixty grammes of fer- 

 ment, th«re remained forty grammes of a fubftance, which I 

 believed to be more animalized than the ferment itfelf. I was 

 much furprifed to find, that I obtained from it by diftillation 

 much lefs ammonia. Hence I fufpedted, that by mixing it 

 afreih with fugar, fermentation would again take place, and 



thus 



