jfi On the Identity of the Pjromucous, 



from gums, honey, manna, ftarch, paper, and feveral other 

 vegetable fubftances which are known to yield pyromucous 

 acid by diftillation. 



2. White and purified tartar gave by the retort nearly a 

 hali'lefs of acid liquor, than fugar furniihed of pyromucous 

 acid. This tartareous acid product, obtained by a weil re- 

 gulated heat, was almoft tranfparent, and had not the red- 

 difh-brown colour of the empyreumatic acids extracted by 

 means of a flrong heat. It however had an acrid enipy- 

 Teumatic odour, a heavy and highly coloured oil floated over 

 it, and, notwithftanding its pungent nature, it would have 

 been difficult to afcertain it to be acetous acid by this flngle 

 experiment : but it did not long deceive us. Having fatu- 

 rated it with potafh immediately, on account of its little 

 colour and impurity, we diftilled it, after being evaporated 

 to drynefs, with diluted fulphuric acid, and it furniihed acetous 

 acid, eafy to be diftinguifhed as fuch, without any mixture of 

 ♦mpyreuma. 



We found that by diftilling pyrotartareous acid, even not 

 rectified and in a red ftate, front off pounded charcoal, previ- 

 oufly well lixiviated and carefully dried, it loft by this fimple 

 operation its empyreumatic nature : we are even perfuaded 

 that mere filtration of this acid warm, through charcoal, fe- 

 veral times repeated, would be fufficient to feparate from it 

 the oil, and to bring it to the date of acetous acid almoft pure. 



No doubt, therefore, can remain, that the pyrotartareous 

 acid is acetous acid rendered impure by a portion of empy- 

 reumatic oil produced by the decompofition of the tartareous 

 acid bv caloric. 



3. The pyro-ligneous acid obtained from fhavings of beech 

 wood, diflilled with care, formed with lime a brown fait not 

 cryftallifuble. This fait, when treated with very weak ful- 

 phuric acid, gave acetous acid, known by its fmell, the de- 

 liquefcent acetite it formed with potafh, or the cryftallifable 

 acetite obtained from it with foda. 



Another portion of the fame primitive pyroligneous acid,, 

 when immediately united to potafh, and filtered in its folu- 

 tion through powdered charcoal, gave an acetite of potafh 

 almoft colourleis, from which weak fulphuric acid disengaged, 



by 



