44 ON THE PYROTARTAROUS ACID. 



IX. 



Experiments on the Tar tarous Acid, and particularly on the 

 Acid it affords by Distillation in the dry Way : by Messrs. 

 Fourcroy and Vauquelin*. 



Fyro! igneous* JlVJLESSRS. Fourcroy and Vauquelin having examined 

 ad&'fbunTto t ^ ne py ,on g neous anc * pyromucous acids in the year 8, found 

 be compounds that they were formed of acetic acid and an empyreumatic 



©f the acetic, j] # Having afterward examined the pyrotartarous acid, 



aod the pyro- . ° . ... l J 



tartarous sup- they perceived, that it was volatile; and that with potash it 



posed to be the con i posed a salt in foliated crystals with the appearance of 

 mother of pearl, attracting moisture from the air, having a 

 pungent and acid taste, totally soluble in alcohol, and emit- 

 ting a pungent acid smell when acted on by sulphuric acid. 

 From these experiments they inferred, that tartar afforded 

 by distillation the same acid as gum, starch, wood, &c. : 

 and in fact it was scarcely possible, to form any other con- 

 clusion: for beside the properties of the pyrotartrite of pot- 

 ash, which are nearly the same as those of the acetate, their 

 opinion was supported by analogy, 

 but this ques- But Mr. Gehlen having said in a letter printed in the 

 Annales de Chimie for October 1806, that he could not be- 

 lieve the pyrotartarous acid to be the acetic, because, after 

 slow evaporation it left a crystallized residuum, which dif- 

 fered too from tartarous acid, Messrs. Fourcroy and Vau- 

 quelin have examined the pyrotartarous acid anew, and the 

 following is the result of their inquiries. 

 Pyrotartarous »• 1 ne ac ^ liquor obtained by the distillation of tartar 

 acid combined being saturated with carbonate of potash, a part of the oil 

 * K)ai>u dissolved by this acid was precipitated in the form of a 

 brown resin, yet a large quantity remained in the new com- 

 pound. 

 The salt crys- 2. This compound, evaporated to dryness and redissolved 

 taitized. several times in water, yielded a salt of a brownish colour, 



* Annales de Chimie, vol. LX1V, p. 42. 



a hot 



