274 PROCEEDINGS OF THE AMERICAN ACADEMY. 



time with constant stirring. Tiie beaker was cooled by immersing it in 

 ice. The precipitate was washed with benzol until the filtrate was color- 

 less, and then dried on a porous plate and in vacuo. Analyses I. and II. 

 are of two different products prepared in this way. As in these prepara- 

 tions and the other similar ones described in this paper we had used three 

 molecules of the sodium compound to one of the nitro body, there seemed 

 some danger that our products might be not definite compounds, but 

 mixtures of an addition compound containing only one atom of sodium, 

 with the two additional molecules of the sodic malonic ester (or the 

 corresponding reagent) precipitated by the large excess of the benzol. 

 This objection to our results did not seem a very important one, because 

 they agreed better with the theoretical numbers than would be probable if 

 this theory were true, but we felt that it was necessary to test it by ex- 

 periment, and for this purpose repeated the preparation, using two mole- 

 cules of sodic malonic ester to each molecule of trinitrobenzol (1 gram of 

 trinitrobenzol and 1.7 grams of the sodic malonic ester). Analysis III. 

 was made with the specimen prepared in this way, and proves that our 

 substances are definite compounds and not mixtures, since it agrees with 

 those prepared with three molecules of the sodium ester. 



I. 0.2038 gram of the substance gave 0.0544 gram of sodic sulphate. 



II. 0.2154 gram of the substance gave 0.0590 gram of sodic sulphate. 



III. 0.2630 gram of the substance gave 0.0756 gram of sodic sulphate. 



Calculated for Found. 



CcH3(N02)3[CHNIa(000C„H5)2]3. I. II. III. 



Sodium 9.09 8.66 8.87 9.31 



Properties of the Addition Product of Trinitrobenzol and Sodic Malonic' 



Ester, CeH3(N02)3[CHNa(COOaH5)j3. 



This body has a rich maroon color brighter than that of the corre- 

 sponding compound of trinitranisol and sodic malonic ester. It is stable 

 for some time if kept dry and cool, otherwise it gradually undergoes 

 decomposition, as shown by its change of color and becoming gummy. 

 In its other properties it resembles the corresponding trinitranisol com- 

 pound most closely. When treated with hydrochloric acid the color is 

 destroyed, and a thick oily brownish yellow precipitate is formed ; by 

 washing this with small quantities of alcohol to remove the malonic ester 

 the trinitrobenzol was recovered in quantity, and recognized by its 

 melting-point, 121°-122°, after recrystallization from benzol. As soon, 

 therefore, as the three atoms of sodium are replaced by hydrogen, the 

 addition product splits into its constituents. 



