Thenard mixed 60 parts of yeast with 300 parts of sugar, and fermented the mixture at the temperature of 59°. He informs us that, in four or five days, all the saccharine matter had disappeared. The quantity of carbonic acid evolved amounted by weight to 94-6 parts. It was perfectly pure, being completely absorbed by water. The fermented liquid being distilled, yielded 171*5 parts of alcohol of the specific" gravity 0 822. When the residue of the distillation was evaporated, 12 parts of a nauseous acid substance remained, and 40 parts of the yeast still continued unaltered in appearance, though Thenard assures us that it had lost the whole of its azote. Thus the products of the fermentations were,

Alcohol of 0-822, 171*5

Carbonic acid, 94*6

Nauseous residue, 12*0

Residual yeast, 40*0


Loss, 41-9

But as the nauseous residue and residual yeast ^ nearly make up the quantity of yeast employed, let us consider only the products of decomposed sugar, supposing the loss to be proportionally divided between the carbonic acid and alcohol. Now, alcohol of the specific gravity 0 822 contains one-tenth of its weight of water, which can be separated from it; and if we suppose, with Saussure, that absolute alcohol contains 8*3 per cent, of water, then the products of sugar decomposed by fermentation, according to Saus-sure's experiments, are as follow :

Alcohol, 47*70

Carbonic acid, 35*34

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