72 Dr. Wall on the Origin of the 



mentation, appears evinced by the celebrated 

 Scheele% curious analyfis of the tartar of wine. * 



This fubftance was long confidered fimply as 

 a peculiar acid, debafed, perliaps, by a large 

 adnnixture of earthy matter : but no one before 

 Mr. Scheele ever conceived, that it was a neutral 

 fait, with a vegetable alkaline bafe. Yet fuch 

 his experiments have fhewn it to be, the alkali 

 being, however, furperfaturated with the vegeta- 

 ble acid. 



His principal experiment (which I relate, not 

 as fuppofing it unknown to the Gentlemen of the 

 Society, but only to recal it to their remem- 

 brance) was as follows : 



He diflblved cream of tartar in a fufficient 

 quantity of boiling water, and added fine chalk 

 in powder to it until the effervefcence ceafed : 

 a copious white fediment fell to the bottom, 

 which was the chalk, combined with a part of the 

 acid of tartar; and the liquor, that floated above 

 the precipitate, afforded, by careful evaporation, 

 a cryftallization of foluble tartar, which is a 

 compound of the acid of tartas, with the vegeta- 

 ble alkali. Though perfectly fatisfied of the 

 accuracy of Scheele^ and of Dr. Blacky who re- 



* The original account of thefe experiments is given In 

 tlie Swedifti Tranfadllons for the year 1770, but as that work 

 is not common in this kingdom, it may be ufeful to refer to 

 an Abftradl of this Memoir in the Medical Commentaries, 

 Vol. I. p. 3:0. 



peated 



