OF ARTS AND SCIENCES. 281 



The formation of this substance by heating the bromdinitrophenyl- 

 acetacetic ester with hydrochloric acid is not a good method of prepar- 

 ing it, because the process must be carried on in sealed tubes, and also 

 because the product is apt to be contaminated with the tarry impurity 

 just mentioned; but as it throws light on the reaction which takes 

 place, we will describe it briefly: 1 gr. to 1.5 grs. of the ester were 

 sealed in a tube with 20-30 c.c. of pure strong hydrochloric acid, and 

 heated from 130°-150° for two or three hours. Upon opening the 

 tube a gas was evolved, which burnt with a smoky green-bordered 

 flame (ethylchloride), aud also contained carbonic dioxide, as shown 

 by its giving a precipitate with lime-water. The contents of the 

 tubes consisting, in addition to the acid liquid, either of tufts of brown- 

 ish acicular crystals, or a brown oily semi-solid mass, were poured into 

 a large volume of cold water, and the insoluble portions purified as 

 already described. 



The following analyses were made in part with substance prepared 

 by the hydrochloric acid process, and in part with that made with 

 sulphuric acid : — 



L 0.2312 gr. of the substance gave on combustion 0.3005 gr. of 



carbonic dioxide, and 0.0546 gr. of water. 

 II. 0.1638 gr. of the substance gave 14 c.c. of nitrogen at a tempera- 

 ture of 23° and a pressure of 755 mm. 

 III. 0.1862 gr. of the substance gave, according to the method of 

 Carius, 0.1173 gr. of argentic bromide. 



III. 



26.81 



It is evident from the analyses and observations given above that 

 the reaction with hydrochloric acid runs as follows: — 



C G H 2 Br(N0 2 ) 2 CH 3 COCHC0 2 CJL + HC1 = 



C 2 H 3 C1 + C0 2 + C 6 H 2 Br(N0 2 ) 2 CH 3 COCH 8 ; 



and that the reaction with sulphuric acid must be similar. We had 

 expected that bromdinitrophenylacetic acid would be formed also by 

 these processes, but after a most careful search for it not a trace could 

 be detected; and as its properties are so striking that we could not 

 have overlooked it, the conclusion is forced upon us that the reaction 



