264 PROCEEDINGS OF THE AMERICAN ACADEMY 



II. The same weights under the same conditions gave 9.08 grs. of 

 argentic bromide, corresponding to o.SG grs. of bromine. 



If two atoms of bromine had been removed, the amount of bromine 

 should have been 3.55 grs. Therefore the percentages of the theo- 

 retical bromine removed as sodic bromide were, — 



I. ii. 



105.9 108.8 



It appears, therefore, that a little more than the amount calculated 

 for two atoms of bromine has been removed as sodic bromide, and this 

 is easily explained by the observation described later in this paper, 

 that sodium malonic ester can act on the bromtrinitrophenylmalonic 

 ester even in the cold to form the trinitrophenylendimalonic ester, a 

 small quantity of which was undoubtedly formed in these two experi- 

 ments by the large excess of sodium malonic ester present. At any 

 rate, there can be no question that all the bromine was removed in the 

 form of sodic bromide. 



The next step consisted in determining the nature of the organic 

 secondary product. For this purpose, the oil, separated from the 

 bromtrinitrophenylmalonic ester by sucking out the crude product on 

 the pump and treatment with alcohol, was allowed to stand till it 

 ceased to deposit crystals of the ester, and then submitted to distilla- 

 tion under diminished pressure. The pressure varied from 22 to 25 

 mm., and a distillate began to appear when the thermometer inside 

 the flask stood at 98°, and was collected until the temperature had 

 reached 1G0°, when about one third of the total volume had passed 

 over. In this way a clear yellow liquid was obtained, which distilled 

 unaltered at ordinary pressure between 197° and 206°. We there- 

 fore inferred it was mostly malonic ester, boiling point 197°. 7, a view 

 of its nature which was confirmed by its smell. As the whole of the 

 distillate passed over below 206°, there could be no large amount ot 

 tartronic ester (boiling point 220°) present, which we had expected 

 after the work of one of us and W. S. Robinson on the corresponding 

 dinitro compound, and the secondary product of the reaction must be 

 looked for in the residue which had been left behind in the flask after 

 the distillation under diminished pressure. This was a thick blackish 

 brown oil, which on standing for about a week deposited crystals all 

 over its surface ; these were removed and allowed to stand on filter 

 paper until a large part of the oil had been sucked out, when they 

 were purified by washing with a small quantity of cold alcohol, and 

 then crystallizing from boiling alcohol, until they showed the constant 



