'Z6z On the Cultivation of the Vifii, 



vital air, or, perhaps, of the dcftruvSlion of mephitic air in 

 the atmofphere, to conipeniate the loflcs it fuilains, and to 

 maintain conftantly the quantity requifite for the prefervation 

 of the inhabitants of the earth, without producirtg a conti- 

 nueci increafe or diminution in the aerial fuhftances of which 

 the atmofphere is compofcd. What diforders might enfue 

 if a few hundredth parts of vital air only were wanting? 

 Fire would lofe it? ilrcngth, candles would not diffufc fnch 

 complete light, and animal& would with difficulty receive 

 the vivifying air. No Icfs inconveniences would arife. if the 

 atmofphere, on the other hand, were more charged with vital 

 than mephitic air. Animal^i indeed, by thcfe means, would 

 acquire a freer refpiration^; but let us only confider the 

 acS:ivity which flit would acquire by air of fupcrior purity. 

 We know that, on fome occafions, the leart fpaik excites the 

 ftrongeft flame in a combudible body, and which increafes 

 fo much as to confume it in a few moments: candles then 

 would be no fooner lighted than tbev would be defiroycd, 

 without 'anfwering any other purpofe than that of dazzling 

 us for a few moments: iron would be calcined, indead of 

 acquiring from the tire that foftncfs necelHiry for transform- 

 ing it into various inftruments, and which it cannot receive in 

 a more moderate heat. Nothing would be capable to check 

 the progrefs of this dcftructive clement, which is nouridied 

 by vital 'air, if this aeriform fubfiance were not abundantly 

 mixed with mephitic air, which fervcs to rcftrain it. 



XXXII. A Trcatifc on the Cultivation of the Viiie, and the 

 Method of making Jpi?ies, By Q. Ckaptal, 



[Cgntiiiucd from Pdge 134.] 



in. Of the Means re^ui/tte to difpofe the IVinefor Fcrmen^ 



tation, 



J\S ripe grapes rot on the twigs, the faculty which the 

 fweet and faccharine juice of the fruit poflefies of being con^' 

 verted into a fpiritous liquor may be confidered as the pur'©' 

 effect of art, and it is by the fermentation of this juice ex-' 



prcOcd 



