248 PROCEEDINGS OF THE AMERICAN ACADEMY 



I. 0.1674 gr. of the salt dried at 100° gave, after being heated with 

 fuming nitric acid in a sealed tube * and precipitated with 

 potassic bromide, 0.0761 gr. of argentic bromide. 

 II. 0.1556 gr. of the salt treated in the same way gave 0.0707 gr. 

 of argentic bromide. 



Calculated for Found. 



C 6 H 2 Br(N0 2 ) 2 CH 2 CO,Ag. I. II. 



Silver 26.21 26.11 26.10 



Properties. — The argentic bromdinitrophenylacetate forms white 

 flat prisms terminated by a single plane at an oblique angle ; the ter- 

 minated end is somewhat broader than the other, so that the crystals 

 look like a flattened base-ball bat. They have also a tendency to 

 twin longitudinally. When put in the flame of a Bunsen lamp, they 

 burn with a sparkling flame, but when heated carefully on a piece of 

 porcelain, decompose quietly leaving a residue of silver. The sub- 

 stance is very slightly soluble in cold water, so that it can be washed 

 without too great loss ; more soluble in hot water, from which it crys- 

 tallizes apparently without decomposition ; insoluble in cold alcohol, 

 but slowly decomposed, if heated with it. 



Constitution of Bromdinitrophenylmalonic Ester. 



The formation of metabromdinitrotoluol from bromdinitrophenyl- 

 malonic ester by a series of reactions giving essentially a quantitative 

 yield and taking place at temperatures not above 150°, throws a great 

 deal of light on the nature of this substance. In the first place, its 

 conversion into a toluol derivative is a welcome confirmation of the 

 formula which we have given it, and which did not rest on the most 

 secure experimental foundations. In our first paper it was stated that 

 the analysis left the choice open between the following formulas, 



I. C,H,Br(N0 2 ),CH(COOC,H 5 ) 2 , 



II. C 6 HBr(N0 2 ) 2 C(COOC 2 H 5 ) 2 , 



and we decided in favor of the first on account of the analyses of the 

 sodium salt, an amorphous substance for the purity of which we had 

 no guaranty, and also on account of the ease with which this salt was 

 formed and decomposed, the product of the decomposition being the 

 original ester. Against this formula stood only our inability at the 



* We had hoped in this way to determine both the silver and bromine in one 

 operation, but found that the filtrate gave a precipitate with potassic bromide. 

 It would seem, therefore, that the presence of an excess of argentic nitrate is 

 necessary to retain all the bromine. * 



