108 PROCEEDINGS OF THE AMERICAN ACADEMY. 



were often thick, especially when having the complex form last described. 

 The substance turns yellow on long exposure to the air, and imparts to 

 alcohol a marked crimson color, which has also been observed on the 

 ground glass stopper of the bottle in which it was kept. In this case the 

 color may have been due, however, to some alkali from the glass, but this 

 was not the case in the alcoholic solution, as the color was only partially 

 discharged by acidification. The modification melting at 58° forms 

 similar crimson solutions. It melts at 64:° to a red TKUiid. Its solubility 

 in the organic solvents is essentially the same as that of the form melting 

 at 58° ; that is, it is very soluble in chloroform, ether, benzol, or glacial 

 acetic acid ; somewhat less so in carbonic disulphide ; soluble in cold 

 alcohol, freely in hot, rather more soluble in methyl than in ethyl alcohol ; 

 insoluble in ligroine, or cold water, slightly soluble in hot water. 



The action of acids upon this more stable trinitrophenylmalonic ester 

 is described in some of the following paragraphs of this paper. Alkalies 

 give with it dark red salts, which crystallize well. The ammonium salt 

 is especially characteristic ; it was made by adding an excess of aqueous 

 aramonic hydrate to a wanm nearly saturated alcoholic solution of the 

 trinitrophenylmalonic ester. The solution took on a deep purplish red 

 color, and in a few seconds the whole solidified to a thick semisolid mass 

 havino- the purplish red color and consistency of clotted blood. A micro- 

 scopic examination showed that this mass- was made up of long very 

 slender hair-like crystals, which after drying had a rich golden brown 

 color and a silky lustre. The salt decomposed below 100°, at first turn- 

 ing black, but afterward melting to a clear yellowish liquid, which ex- 

 ploded at higher temperatures. It is rather sparintrly soluble in water; 

 soluble in alcohol, chloroform, or acetone ; insoluble in ligroine. The 

 solutions have a dark red color, but if the solution in water or alcohol is 

 boiled for some time it turns yellowish brown ; unfortunately no product 

 could be obtained from such solutions in a state fit for analysis. 



An aqueous solution of the ammonium salt gave the following charac- 

 teristic precipitates. 



With salts of barium an abundant crystalline amethystine precipitate. 



With salts of strontium a dark red precipitate. 



With salts of calcium a brick-red precipitate. 



With salts of zinc an abundant crystalline scarlet precipitate, turning 

 to reddish brown on standing. 



With salts of cadmium a granular scarlet precipitate. 



With salts of copper a heavy flaky precipitate, varying from reddish 

 yellow to brownish red. 



