pa Onihe Identity of the PyrO'tnucous, Pyro-tariareous, and Pyro-ligiieous Acids, &c. 



Some fafts obferved in the analyfes of vegetables, led our chemifls to fufpeft that thefe 

 acids, which were proved to be the fame, might not differ from the acetous acid, except 

 by foreign additions. They made experiments with a view to confirm their fufpicions. 

 By the diflillation of fugar, ftarch, gum, &c. they obtained the pyro-mucous acid ; by 

 that of tartar, the pyro-tartareous acid ; and by that of wood, the pyro-ligneous acid. 

 They combined thefe acids with an alkaline bafis ; from which, having feparated them by 

 tlic fulphuric acid, they obtained by this means, in fome inftances, with filtration through 

 charcoal powder, an acid and limpid liquor, deprived of the empyreumatic oil, which 

 rendered it impure, and prevented it from being diftinguiflied as the true acetous acid. 

 This liquor then pofTefled the fmell, tafte, and all the other charafters } and, with the 

 alkaline bafes, formed perfeft acetites. 



It was neceflary to attempt to form the empyreumatic acids again by the acetous acid, 

 by imparting to the latter the empyreumatic oil and empyreumatic fmell, of which it had 

 been deprived by the preceding experiments. The following is the procefs employed by 

 Citizens Fourcroy and Vauquelin : — ^They diftilled a portion of acetous acid over the 

 empyreumatic oils of mucilage, tartar, and wood ; and thus formed pyro-mucous, pyro- 

 tartareous, and pyro-ligneous acids. To form thefe acids again inftantaneoufly, it was 

 only requifite to add a few drops of thofe empyreumatic oils to fome acetous acid. 



To thefe fa£ts, which are fufficiently interefting in themfelves, the difcoverers have 

 fubjoined reflexions no lefs important, relative to the frequent produftion of the acetous 

 acid under very different circumflances. 



The acetous acid is not therefore a neceflary produ(fl of the vinous fermentation. In 

 addition to the fa£ts above related, which confirm the produilion of this acid without any 

 fermentation, it may be obferved, that many fubftances, of a nature very different from 

 wine, contain acetites; fuch are the fap of vegetables kept only a few hours, foils, heated 

 tan, the four water of the ftarch matter, four pulfe, and four fruit, expofed for fome hours 

 to a hot air. Milk, animal jellies, and that part of urine called uree, when they become 

 four, likewife afford a great quantity of this acid. 



Citizens Fourcroy and Vauquelin have difcovered four very diftind: circumftances under 

 which the acetous acid is produced, each of which is chara£lerifed by fome particulars 

 relative to the phenomena of its produftion. 



The firft mode of acetijication is the decompofing aftion of fire : in this cafe water is 

 difengaged with carbonic acid formed from the difengaged carbon ; and the acetous acid 

 thus obtained is diftlnguifhed by its colour and empyreumatic odour. 



The fecond method confifts in the application of the powerful acids, fuch as the ful- 

 phuric, nitric, and the oxigenated muriatic acids upon vegetable compounds, fuch as 

 fugar, jelly, &c. ; alcohol and the vegetable acids thernfelves, except the acetous acid, 

 are entirely decompofed by thefe acids. Some water and carbonic acid are alfo produced, 

 and the acetous acid thus obtained contains oxalic acid, malic acid, and much water. 



The 



