Pyrolartareous, and Pyrsllgneous Acids. 5 1 



fedge of the chemical phenomena exhibited hy vegetable 

 fubftances in reward to their acidification in general, enables 

 hs to obferve and diftinguifh four circumftances which pro- 

 mote their acetificatiou or converfion into acetous acid. 



The lirft is, the deeompofiog aftion of the fire in diftilla- 

 tion. Without here entering into more extenfive details 011 

 this fubject, which, when we confider the objeft of this me- 

 moir, are lefs neceflary, we fhall content ourfelves with ob- 

 ferving, that this action of caloric, by difuniting the con- 

 ftituent principles of vegetable matters, combines a part of 

 them in finch a manner as to give birth to acetous acid; and 

 that this converfion is accompanied with the formation of 

 water, the formation and difengagement of gafeous carbonic 

 acid, and the precipitation of carbon in the Hate of charcoal. 

 The fecond mode of acetification of vegetable compounds 

 is that arifing from the action of powerful acids, and parti- 

 cularly of the fulphuric, the nitric, and the oxygenated mu- 

 riatic on thefe compounds. This kind of production takes 

 place in gums, fugar, extracts, and gelatin, when treated by 

 acids ; the greater part of the other vegetable acids, and even 

 alcohol itfelf, often experience fuch a change by the decom- 

 pofing influence of the acids above mentioned. While this 

 kind of acetification takes place, there are formed alfo water 

 and carbonic acid ; fometimes carbon likewife is depofited. 

 We muft here add, that this acetification is the laft term of 

 vegetable acidification in general, fince in treating acetous 

 acid by the fame decomposing a£tion of the mineral acids, 

 vou deftcoy its acetous nature, and make it pafs to the ftate 

 of water and carbonic acid, as is the cafe in every vegetable 

 decomposition carried to its maximum. 



The. third mode of acetification is the oldeft known of the 

 whole, and the only one formerly admitted : it is the acetous 

 fermentation that converts all the different kinds of wine into 

 vinegar: in this there is neither a precipitation of carbon, nor 

 difengagement of carbonic acid. It is well known that it 

 takes place in conlequence of an abforption of the oxygen of 

 the atmoiphcre, and that it fuppoles the piecxiltence o. 

 \inous liquors. 



In the laft place, wc confider as the fourth and laft mode 

 Hi of 



