*>& HISTORY OY THfe GAIUC ACIP. 



XI. 



Facts toward a His tory of the Gallic Acid. By Bouillon 

 Lagrange."* 



Jl HAVE had the honour of submitting to the class the result 



of my experiments on tannin ; I now lay before it some facts 



respecting the gallic acid, which I had announced as forming 



the second part of my memoir. 



H'storyofthe Of all the vegetable acids, the gallic may he considered as, 

 galjie acid. . 



. most interesting, and accordingly it has been a subject of inquiry 



to many chemists. Macqucr, Monnct, Lewis, Cartheuscr, and 

 Gioanetti, pointed out the manner, in which solutions of iron, 

 are acted upon by substances called astringent. The acadc- 

 miciansof Dijon were the first, who observed the presence of an 

 acid in those subtances ; and in 1772 they shewed, that the 

 distilled products of nutgalls blackened the solution of sulphat 

 of iron, and that an infusion of them reddened the tincture of 

 bitmus. These particulars afforded only a general proof of the 

 acid nature of the principle contained in galls ; offering no 

 means ofextiacting this acid, and obtaining it separate, for 

 Sch'eete first which we are indebted to Scheele. His process was published 

 Deveu^sub- in J' 80 - A few years after, in 1793, Mr. Deyeux discovered 

 limed it. that this acid might be obtained by sublimation. Messrs. 



Berthollet and Proust afterward added much by their researches 

 to our knowledge of the properties of this acid j so that it 

 might be considered among the best known <>f all that the vege- 

 table kingdom produces. 



Several foreign chemists too, within these few years, have. 



given processes for extracting and purifying this acid : but none 



Some facts by of them, except Kichter's, can come in competition with 



Bartholdi Scheele's. Among the many experiments, that have been 



'U)UOtic3(l. . ' . . i • i . i 



made on this subject, there is one, which I have neither seen 

 refuted nor quoted in the papers published on the gallic acid. 



In a letter from Mr. G. C. Bartholdi to Mr. Berthollet, 

 dated 17.92, there are some facts, that might have claimed the 

 attention of chemists. 



* Annates de Chimie, Vol. LX. p. 1^5, Nov. 18Q6> 



