130 PROCEEDINGS OP THE AMERICAN ACADEMY. 



substances obtained by acidifying them with acetic acid were so tarry th^t 

 we could not isolate any body fit for analysis. The filtrate from this tar, 

 which was also colored, was evaporated to small bulk, and treated with 

 baric chloride, when a gelatinous precipitate was obtained, which resem- 

 bled the barium salt of tribromnitrophenol described later in this paper. 

 We did not however succeed in getting enough of it to purify for 

 analysis. 



The approximate yields of the principal products of the action of sodic 

 ethylate on tribromdinitrobenzol at 70° were determined as follows : — 



Dinitroresorcine Diethylether 16 per cent. 



Bromdinitroresorcine Diethylether melting at 92° . 9 per cent. 



Total 25 per cent. 



From which it appears that 75 per cent of the theoretical yield had been 

 converted into the tarry mass, from which we could isolate nothing fit 

 for analysis. 



Action of Sodic Ethylate upon Tribromdinitrobenzol in the Cold. 



The proportions used were the same as those used in the experiment 

 at 70°, that is, 40 grams of the tribromdinitrobenzol dissolved in 80 c.c. 

 of benzol and mixed with the sodic ethylate from 6.8 grams of sodium 

 and 180 c.c. of absolute alcohol. The mixture was allowed to stand in 

 a corked flask from three to five days with frequent shaking, after which 

 it was poured into an evaporating dish, and allowed to evaporate spon- 

 taneously. The residue was washed with water, until the washings 

 were colorless, and the products were then purified as follows. 



Residue Insoluble in Water. 



This was dried, and extracted three times with boiling ligroin, which 

 left a crystalline residue, and this after recrystallization from a mixture 

 of alcohol and benzol showed the constant melting point 184°, and was 

 therefore the bromdinitroresorcine diethylether discovered by W. H. 

 Warren and one of us in the previous work on this reaction. 



The ligroin extract was allowed to stand over night, when it deposited 

 crystals, which were filtered out, and strangely enough proved to be 

 essentially insoluble in ligroin. As they could not have been formed in 

 the ligroin solution, we can explain the extraction of them by hot ligroin 

 only by supposing they are soluble in a mixture of ligroin and the 

 other (soluble) product of the reaction. The crystals after purification 



