1G8 PROCEEDINGS OF THE AMEUICAN ACADEMY 



give here, however, the result of a determidation of the amount of 

 sodic bromide formed iu the reactiou. 5 gr. of tribromdinitroben- 

 zol were treated in the cold with the sodic ethylate from 0.9 gr. of 

 sodium iu tlie manner described above, and, after the reaction had 

 come to an end, water was added, the benzol solution removed, and 

 the water extracted three times with benzol, after which it was made 

 up to a volume of 500 cc, and the amount of sodic bromide deter- 

 mined in 20 cc. of this solution ; the weight thus obtained calculated 

 on the whole solution gave the result given below as found. The 

 calculated number is the amount of sodic bromide which would be 

 formed if two of the atoms of bromine in the tribromdinitrobenzol 

 had been removed. 



Calculated. Found. 



Sodic Bromide 1.271 gr. 1.194 gr. 



These results agree as closely as could be expected considering the 

 unavoidable losses in extracting with benzol, and prove that in this 

 case two of the atoms of bromine contained in the tribromdinitroben- 

 zol were removed as bromide of sodium. 



Properties of Bromdinitroresorcine Diethylether, 



CeHBr(C2Hp),(NO,)2. 



The substance crystallizes from alcohol in rather thick flattened 

 needles of a yellowish white color, which may attain a length of 1 cm. 

 and sometimes a breadth of 1 ram. The ends are usually square, 

 but less often consist of two planes at a very obtuse angle to each 

 other. The larger crystals seem to be made up of needles united 

 longitudinally, since their ends are apt to be sharply serrated, or 

 even as much indented as the teeth of a comb. Crystallized from 

 benzol it formed long slender prisms, sometimes reaching a length of 

 2 cm., terminated by two planes at an acute angle to each other, and 

 efflorescing on exposure to the air. They showed however the same 

 melting point as the crystals obtained from alcohol, and when recrys- 

 tallized from this solvent gave the plates with square ends described 

 above ; they probably contained benzol of crystallization, which 

 escaped before the temperature had risen to the melting point of the 

 substance. It melts at 184° ; and is not very soluble in alcohol even 

 when hot, less so when cold ; slightly soluble in methyl alcohol ; 

 nearly insoluble in cold water, very slightly soluble in hot ; freely 

 soluble in acetone ; soluble in benzol or chloroform ; slightly soluble 

 in ether or glacial acetic acid ; nearly insoluble in carbonic disulphide ; 

 and insoluble in ligroine. Alcohol, or alcohol with a little benzol, is 



