Diffinnce between the Acetous and Acetic Acids. 519 



T . That no fuch thing as the acetous acid exifts. 



2. That the acid of vinegar is always at the higheft poffible degree of oxygenation ; and, 

 Confequently, is always acetic. 



3. That the difference between the acid obtained by the diflillation of vinegar, and that 

 afforded by the like procefs from the acetate of copper, depends on the lefs quantity of water 

 •contained in the latter. , 



I muft confefs, that notwithftanding the high degree of confidence I place in the labours of 

 Citizen Adet, it has been impoffiblc for me to adopt his conclufions in this refpeft ; and as I 

 was very far from calling his experiments in queftion, I have thought it proper to analyfe, 

 compare, and difcufs, his refults, much lefs with the view of afcertaining their accuracy, 

 than to dcterrtiine whether they juftify the confequences deduced from them by their author. 



I conclude, therefore, immediately with Citizen Adet, that it appears to be demonftrated 

 by his experiments, that the oxygen exifts nearly in equal proportions in the diftilled acetous 

 acid and the acetic acid ; that it is equally difficult, and even impoffible, to oxygenate the 

 acetous acid, and to' difoyxgenate the acetic ; and that moft of the fait feparately formed by thefe 

 two acids are of the fame nature. Thefe confequences, no lefs new than interefting, belong 

 to Citizen Adet, and naturally flow from his experiments. 



But to conclude, from the fame fafts, that the acetous and the acetic acids are exaCtly the 

 fame, and differ only in their proportions of water, is more than the experiments will juftify ; 

 and while we muft agree with Citizen Adet as to the truth of his firft confequences, it may 

 alfo be fhewn, that there is a very great difference between the acetous diftilled acid, and the 

 acetic. I fliall endeavour to afcertain the caufe of this difference. 



The two acids in queftion differ, no doubt, in fmell, in tafte, and folvent power ; but as 

 the caufe of thefe differences might be referred to their refpective degrees of concentration, 

 I have thought it proper to bring both to the fame fpecific gravity, by diluting the acetic acid 

 with a fufficient quantity of diftilled water ; and it was with thefe two acids, at the fame 

 degree, that I made the following obfervations and experiments : 



1 . The fmell and tafte fliew the difference between thefe two acids. The effe£ls, in this 

 refpe£t, are more evident, and the fenfation is much more penetrating on the part of the 

 acetic than the acetous acid. 



2. The adtion of the acetic acid on the lips, and upon the metallic oxydes, is more fpeedy 

 and energetic than that of the acetous acid. Thefe two acids, fet to digeft in equal portions 

 upon the oxyde of copper, precipitated fr<5m the fulphate by pot-afti, wafhed, and then 

 diftilled, prefented very different refults. The acetic acid diffolved the oxyde, and formed 

 beautiful cryftals by cooling ; but the acetous was fimply coloured of a blueifh green, and 

 let fall nothing but a green faline cruft, on the borders of tlie fluid. 



Neither of thefe acids perceptibly attacked copper. They merely acquired, by long 

 digeftion, a light green fhade of colour. 



Eleven parts of the acetic acid required for their faturation 6,98 of pure pot-afti ; the 

 fame quantity of acetous acid required only 5,73- 



There, confequently, exifts a difference between thefe oxydes. The following experiments 

 will fhew in what this difference confifts, and render us acquainted with its caufe : 



3X2 ■ ^ I. If 



