Application of Tannin as an Alkaloimeter. 45 
Fifteen grammes of the solution of tannin being introduced 
into the graduated measure of Decroizille's alkalimeter, 
marked 33.07, showing that each division represented 0.0168 
grains by the salt of antimony, or for 100 grammes = 220 
divisions, 3.71 grains, (this solution is what I shall call the 
alkaloimetric liquid.) Afterwards having taken one grain of 
very pure quinine, and one grain of equally pure crystallized 
cinchonine, well dried, I dissolved them in a certain propor- 
tion of distilled water, acidulated with three or four drops of 
sulphuric acid. 
To these limpid solutions, the alkaloimetric liquid was 
carefully added, carefully noting the number of divisions re- 
quired to produce precipitation. The tannate which was 
formed, was white, curdy and almost insoluble in water ; 
when the precipitate was so large as to lead me to suppose 
that it was almost complete, I saturated the acid in the fluid 
by means of a few drops of ammonia, and added more of 
the test, till a precipitate no longer took place. On observing 
the number of divisions on the scale, and multiplying them 
by 0.168, I ascertained the quantity of tannin used. With 
the quinine, the divisions indicated, of pure tannin, 2.5 grains, 
and with the cinchonine, 2.71 grains, consequently, by calcu- 
lation, we find that these numbers give for the tannates 
formed : 
Two atoms of tannin and one atom of alkaloid, or 
Quinine 1 atom 2142 ) (28.19. 
Tannin 2 atoms 5376 \ ~ per 1UU \ 71.10. 
Cinchonine 1 atom 2005 ) _ in n S 27.17. 
Tannin 2 atoms 5376 \ ~ P er 1UU ( 72.83. 
These salts may be considered as bitannates ; they are 
acid. I shall make a more detailed examination of them, as 
well as of the neutral tannate of the organic alkalies, but at 
present shall confine myself to the practical conclusions I 
have attained, and which I propose as a new method of al- 
kaloimetry. 
