OP ARTS AND SCIENCES. 235 



has been studied, and we are able to correct some of the preliminary 

 statemeuts made on this subject in our first paper. The product is 

 the bromdiuitropheuylacetic acid 



C.H.Br (NO2) ..CH^COOH, 



which melts at 177°, and is formed, when hydrochloric acid is used, by 

 the following reactions : — 



C6H2Br(NO„),CH(COOC,H.)2 + 2 HCl = 



2 CoH.Cl + C6H2Br(N02)2CH(COOH), = 

 2 aH.Cl + CO, + CeH2Br(N02).,CH2COOH. 



The crystalline silver salt of this acid was analyzed, and proved to 

 have the formula 



C6H2Br(NO.,)2CH2COOAg. Hp. 



With sodic hydrate a deep Prussian green or with an excess a yellow- 

 ish brown solution is formed, from which acids throw down a pale 

 crimson precipitate, or a white one which becomes pale crimson when 

 moistened with alcohol ; none of these substances could be brought 

 into a state fit for analysis, but we found that bromine was removed 

 in their formation. 



The bromdinitrophenylacetic acid is broken up when boiled with 

 alcohol into bromdinitrotoluol and carbonic dioxide ; boiling with 

 water produces the same effect, but much more slowly. A few drops 

 of sulphuric acid prevent the decomposition by boiling water. This 

 conversion into bromdinitrotoluol gave us the means of determining 

 the constitution of the bromdinitrophenylmalonic ester and its deriva- 

 tives ; as Messrs. W. B. Bentley and W. ¥{. Warren have, at our re- 

 quest, worked out the constitution of the substituted toluol, and found 

 that it is as follows : 



CH3 . Br . NO, . KO, .1.3.4.6. 



It follows, therefore, that all the substances mentioned in this and our 

 former paper must have a similar constitution, and that in making the 

 bromdinitrophenylmalonic ester from bromdinitrobenzol the bromine 

 atom replaced by the malonic radical is one of those which is at the 

 same time para and ortho to the nitro groups, the one replaced by hy- 

 drogen is ortho to the two nitro groups, while the third atom of bro- 

 mine, which remains unaltered, occupies exactly the same position as 

 that replaced by the malonic ester radical, — certainly a curious result. 



