Pyrotartareous, and Pyroligneous Acids. 45 



which it- held in folution, it evidently appeared to be that 

 acid. 



When this fact was once afcertained, it was not difficult 

 for us to prefume that the pyroligneous acid, from whatever 

 wood extracted, could only be acetous acid : we had even 

 reafon to lufpect that the two other empyreumatic acids 

 were of the fame nature; but as a conjecture, however well 

 founded, has no real value in phyfics, we called in the aid 

 of experiment to enable us to difcovcr the truth, or to reject 

 our opinion as an error. 



VI. New Examination of the Pyromucous^ Tyrotafiaredus, 

 and Pyroligneous Acids. 



1. Having diftilled, with great caution, fixteen parts of 

 pure fugar., which furnifhed us with ten parts and a half of 

 water charged with reddifh pyromucous acid, a little more 

 than four parts and a half of light charcoal, and half a part 

 of gas, we combined this acid liquor with lime; the liquor 

 was then evaporated to drvnefs, and afterwards treated in a 

 retort with weak fulphuric acid. We thus obtained a pretty 

 thick, clear, or very little coloured liquid, having a very fen- 

 fible acetous fmell, and which, when combined with potafh, 

 gave a very evident acetite of potafh. This fait, indeed, had 

 a dirty gray colour; but, by filtering a warm folution of it 

 through pounded charcoal, it loft the oil which coloured it, 

 and became quite clear. 



The acid product, obtained from the firft calcareous fait 

 by the fulphuric acid, was alreadv much lefs coloured than 

 the pyromucous acid ; it now retained only very faintly the 

 fmell of caramel (pan fugar), which characterifes the acetoui 

 acid. 



When difengaged a fecond time from alkaline fait by the 

 fulphuric acid, it was Hill purer, had nothing of its firft 

 origin, and now exhaled only a pure acetous odour. Wc 

 had reafon, therefore, to conclude, from thefe experiments, 

 that the pyromucous acid was nothing elfe than acetous acid 

 united to an empyreumatic oil arifmg from the deconjpofi- 

 tion of the fugar by fire. 



The fame refult took place with acid liquors extracted 



from 



