on a Substance possessing the Properties of Tannin. '±<f] 
And acetite of lead immediately formed a very abundant 
precipitate of a yellowish white colour. 
I repeated this experiment on common resin, and remarked, 
that during each distillation nitrous gas was produced, whilst 
the strength of the acid which came over was diminished ; the 
cause therefore of the change in the properties of the resin 
seemed to me very evident, and I was induced to extend the 
experiments to various resinous and other substances ; but as 
the process was uniformly the same, I shall only notice the 
principal effects. 
B. Stick lac, when separated from the twigs, and treated as 
above described, copiously precipitated gelatine. 
C. Balsam of Peru during the process afforded some benzoic 
acid, and gelatine was precipitated by the aqueous solution. 
D. Benzoin also, after the sublimation of some benzoic acid, 
yielded a residuum, which with water formed a pale yellow 
isolution, of a very bitter flavour. 
This solution with sulphate of iron afforded a slight pale 
yellow precipitate. 
With nitrate of lime not any effect was produced. 
The solution with muriate of tin became turbid, and a small 
quantity of brownish-white precipitate subsided. 
Acetite of lead immediately produced a copious pale yellow 
precipitate. 
And solution of isinglass formed a dense yellow precipitate, 
which was insoluble in boiling water. 
E. Balsam of Tolu, like Balsam of Peru, and Benzoin, af- 
forded some benzoic acid ; and the residuum being dissolved in 
water, was found to precipitate gelatine. 
F. As the results of the experiments on dragon's blood were 
mdcccv. Q q 
