OP ARTS AND SCIENCES. 183 



sodic ethylate, it became interesting to find out whether this was 

 the same atom of bromine which undergoes a similar replacement 

 in making bromdinitrophenylmalonic ester, that is, the atom which 

 stands between the two nitro groups, and the easiest way to do this 

 seemed to be to take up the study of the tribromtrinitrobenzol, ia 

 which all the atoms of bromine are similarly placed. This we have 

 done, but without the desired result, as the sodic alcoholates show 

 with tribromtrinitrobenzol actions entirely different from those with 

 the corresponding dinitro compound. 



Action of Sodic Ethylate on Tribromtrinitrobenzol. 



To study this action 10 gr. of tribromtrinitrobenzol (symmetrical, 

 melting at 285°) were covered with ordinary alcohol in a flask, and 

 to the mixture of crystals and alcohol 1.6 gr. of sodium (three atoms 

 of sodium would be a little over 1.5 gr.) previously converted into 

 sodic ethylate was added, in small portions at a time, the flask being 

 immersed in cold water and shaken after each addition so as to avoid 

 a rise of temperature * in any part of the liquid. The first drop of 

 the alcoholic solution of sodic ethylate turned red on touching the 

 liquid in the flask, and then faded to yellow ; but as the remainder 

 of the sodic ethylate was added, the color increased in intensity, until 

 at last it had become a deep blood-red, while at the same time the 

 undissolved solid began to diminish in quantity, and finally entirely 

 disappeared, leaving a clear solution, thus showing that all the tri- 

 bromtrinitrobenzol had been used up, as it is nearly insoluble in 

 alcohol. The mixture was allowed to stand over night, when it was 

 found that a fresh amount of solid had been deposited, the solvent 

 was then allowed to evaporate spontaneously, the residue (including 

 the solid which had separated over night) washed with water until 

 free from inorganic matter, and purified by crystallization from alco- 

 hol until it showed the constant melting point 101°, after which it 

 was dried at about 70° and analyzed, with the following unexpected 

 results : — 



I. 0.3519 gr. of the substance gave on combustion 0.3427 gr. of 



carbonic dioxide and 0.0742 gr. of water. 

 II. 0.2883 gr. of the substance gave on combustion 0.2795 gr. of 

 carbonic dioxide and 0.0G32 gr. of water. 



* If the tribromtrinitrobenzol was dissolved in benzol, the action was so 

 violent that it was almost impossible to avoid a rise of temperature. 



