OF ARTS AND SCIENCES. 265 



melting point 76°. The substance formed long glittering colorless 

 needles or prisms, and contained no bromine ; we decided accordingly 

 that it was the acetylentetracarbonic ester (melting point 76°), and 

 this conclusion was confirmed by the following analysis : — 



0.2270 gr. of the substance gave on combusion 0.4384 gr. of carbonic 

 dioxide, and 0.1506 gr. of water. 



Found. 



52.67 

 7.36 



The amount of acetylentetracarbonic ester was so considerable, that 

 there can be no doubt it was a principal product of the reactions by 

 which the bromtrinkrophenylmalonic ester is formed, and these must 

 therefore be written thus : — 



C 6 Br 3 (NO.v) 3 + 3 CHNa(COOC 2 H 5 ) 2 = 



C 6 Br,(XO,) 3 CH(COOC 2 H 5 ) 2 + NaBr + 2 CHNa(COOC 2 H 5 ) 2 = 

 C 6 Br 2 (N0 2 ) 3 CNa(COOC 2 H s ) 2 + CH 2 (COOC 2 H.) 2 



+ CHNa(COOC,H 5 ) 9 + NaBr = 

 C 6 HBr(N0 2 ) 3 CNa(COOC 2 H 5 ) 2 + CHBr(COOC 2 H 5 ) 2 



" + CHNa(COOC 2 H 5 ) 2 + NaBr = 

 C 6 HBr(N0 2 ) 3 CNa(COOC 2 H 5 ) 2 + C 2 H 2 (COOC 2 H 5 ) 4 + 2 NaBr. 



The only objection which could be urged against this series of re- 

 actions is that the yield of bromtrinitrophenylmalonic ester is only 

 64 per cent of the theoretical, from which it might be argued that 

 nearly half of the tribromtrinitrobenzol may have undergone some 

 different transformation. This objection is disposed of, however, by 

 the fact that W. D. Bancroft and one of us * have succeeded in getting 

 a yield of 80 per cent of the dibromdinitrophenylmalonic ester from 

 tetrabromdinitrobenzol by a series of reactions exactly analogous to 

 those just given. The missing 36 per cent of the bromtrinitrophenyl- 

 malonic ester must therefore have remained dissolved in the oil, and 

 have been destroyed by the distillation even under the diminished 

 pressure used by us. 



Action of Nitric Acid. 



The intense red color produced by the action of nitric acid of spe- 

 cific gravity 1.36 on the sodium, or copper salt of the bromtrinitrophe- 

 nylmalonic ester in the cold, or on the ester itself at 100°, seemed to 



* These Proceedings, xxiv. 295. 



