M. C. Lea on New Coloring Matters. 211 
These experiments appear to me to leave no doubt that picric 
acid is not formed by the action, either brief, or prolonged, of 
nitric acid on picramic acid, but that resinous substances are 
Ee feced, accompanied after a time by oxalic acid, which at a 
5. On the Preparation of Picramic Acid. 
Weare generally directed to dissolve picrate of ammonia in 
alcohol, saturate with ammonia, and then with sulphydric acid. 
These saturations are tedious and troublesome, and as picrate of 
ammonia is but sparingly soluble in aleohol much of the latter 
's consumed, and the solutions are very bulky. The following 
. » ‘- 1. . 
Pierie acid (which is very soluble in strong alcohol) is dis- 
] ia 
water bath, the residue to be exhausted with boiling water, fil- 
tered, and treated with acetic acid. The picramic acid obtained 
in this way is very pure, and the quantity large. In one experi- 
ment where the quantities were weighed, over 63 per cent of the 
Weight of the picric acid consumed was obtained. If too little 
sulphydrate be used, picric acid remains in the mother water 
from which the picramic acid crystallizes, and may be recovered 
Y precipitating with carbonate of potash. 
, Philadelphia, July 13, 1861. 
—_—_— 
Arr. XXVIL—On the Production of néw Coloring Matters by 
{reomposition of Nitronapthaline and Dinitronaphthaline; by 
- Caney Lea, Philadelphia. 
(1) 
In the process for preparing n 
acetic acid and iron on nitronap 
- the caustic alkali, a liquid passes over 
ollowing reaction 
