100 
Pror. A. R. LEEps read a paper on “ Alizarin as a Test.’"* 
He proposed the employment of alizarin in place of litmus 
in volumetric analysis, its extreme sensitiveness rendering it 
capable of detecting infinitesimal amounts of acid or alkali. 
By digesting alizarin with alcohol of 95%, a solution was 
obtained containing 0.00425 grms. of alizarinin onec.c. By 
means of this solution, zscscx part of potash is capable of 
changing zsvs00 part of alizarine from a brilliant yellow to a 
dark red. The delicacy of the reaction is so great that one 
part of soda in three million parts of water, and one part of 
sulphuric or hydrochloric acid in one million parts of water, 
may be recognized with facility. Compared with litmus, 
three times as much litmus and three times as much acid 
are required to produce a corresponding change of color. 
Some experiments were made for the purpose of arriving 
at an approximate quantitative determination of the 
alkalinity of calcic and magnesic carbonates, and the acidity 
of various salts, as compared with the alkaline and acid 
reactions of standard solutions of potash and sulphuric acid. 
A number of samples of drinking water gave a strongly 
alkaline reaction. It was found that distilled water, con- 
densed in a worm of block tin, was invariably alkaline when 
collected in stone-ware jugs, but neutral when collected in 
bottles of white glass. 
For making a test-paper, fine white Swedish filtering pa- 
per isrecommended. Alizarin test-paper is strongly reddened 
by the saliva. Many other examples of the exceeding 
delicacy of the reaction were likewise noted. 
Mr. WM. FALKE read an extended paper ‘ On Adipocere.” 
He gave some account of Fourcroy’s comprehensive investi- 
gation and memoir upon this substance, presented to the 
Academy of Sciences in 1789, and occasioned by the discov- 
ery of immense quantities of adipocere in the burying ground 
connected with the Church of the Innocents, in Paris. 
* Published in full in the American Chemist, vol. IV, p. 333. 
