48 On the Identity of the Pj'ro?nucoux, 



of vinegar, heated in a retort with each of thefe three oils, 

 furnifhed a coloured and odorous product exaclly of the 

 fame nature as primitive pyromucous, pyrotartareous, and 

 pyroligneous acids : the odour and fmell of thefe acids were 

 very perceptible ; only thefe factitious empyreumatic acids 

 were a little ftronger and fourer than thofc arifing from dif- 

 tillation, but nothing more was neceflary to carry them to 

 the fame ftate of weaknefs than to add to them a little water. 



By repeated trial we obtained a manner of forming with 

 the acid of vinegar the three empyreumatic acids much 

 fpcedier, and in a more limple manner, than by difiillation. 

 We found that it was fuffieient to throw fome drops of the 

 empyreumatic oil of mucilages, of tartar, or of wood, into the 

 acetous acid, to fuflfer them to remain fome time together, or 

 to (hake them ftrongly, to imitate thefe acids made by fire. 

 The oil almoft immediately unites with the acid, diflblves in 

 it, gives it a red or brown colour, and communicates to it, 

 at the fame time, the acrid odour and bitter pungent tafte 

 known in the pyromucous, pyrotartareous, and pyroligneous 

 -acids. 



The acetous acid is then a real folvent of empyreumatic 

 oils, and in that cafe it affumes the characters of the acid 

 liquors or odorous fpirits, as they were formerly called, which 

 iffue from vegetable matters treated by fire. To fcparate 

 thefe oils dilTblved in the acetous acid, and to bring back the 

 latter to its purity and to its primitive simplicity, the fame 

 means muft be employed as for freeing the acetous acid from 

 the empyreumatic aciJ.s united to it when obtained by dif- 

 tillation, t/iz. filtration, agitation, ebullition with charcoal, 

 union with lime and alkalies, and the difengagement of thefe 

 combinations by weak fulphuric acid. 



It is to this folnbility of oils in the acetous acid, that the 

 odour which this acid fo eafily acquires and retains feems to 

 be owning: it is to it that we mult afcribe the diitinction of 

 a great number of empyreumatic acids, which feverai che- 

 mifts have been induced to make, and which they could not 

 avoid doing, while continuing to com'icler, in the acid pro- 

 ducts of diililled vegetable matters, the odonr, colour, and 

 favour, .as characters proper, if not for positively afcertaining, 



at 



