OF ARTS AND SCIENCES. 1G5 



metliyliite (in part), and plienolate on tribromdinitrobcnzol, giving 

 C,Iinr(CJI,0),(NOjo, melting point ISr, C,llBr(CII,0),(N0,)2, 

 melting point 237°-2a8°, and CcIIBr(C„H.O)2(NO.,)2, melting po"int 

 165°. 



Third. The replacement of two atoms of bromine by the radical 

 of the alcoholate, and the third by hydrogen. Sodic ethylate when 

 hot, and sodic methylate (in part) whether cold or hot, act in this 

 way on tribromdinitrobeuzol, giving CulIo(C2n^O)2(NO.,)2, melting 

 point 133°, and Curi2(CIl30)2(N02)2, melting at 1G7°. These sub- 

 stances can also be made by boiling the corresponding bromine com- 

 pounds (mentioned under the second class) with the proper alcoholate. 



Fourth. The replacement of one, two, or perhaps three of the 

 nitro groups by the radical of the alcoholate, the three bromine 

 atoms remaining unaffected. This very strange action was observed 

 with sodic ethylate or methylate and tribromtriuitrobenzol, giving 

 CcBr3CJl50(NO,)2, melting point 147°, CeBr3(C2H,0),(NO,), melting 

 point 101°, and C,;Br3(CH30)2(N02), melting point 126°. 



The product of further action of sodic ethylate when hot, on tri- 

 bromnitroresorcine diethylether has not yet been obtained in a state 

 of purity, but we hope to be able to describe it in a later paper. 



We have little to say in general about these different modes of 

 action of the alcoholates, except to connect them with previous ob- 

 servations of a similar character, as we think that the number of 

 facts established is still insufficient for the safe foundation of a theo- 

 retical explanation of these differences. We hope to continue the 

 work, however, until such a foundation has been secured. The 

 formation of the trinitrophloroglucine triphenylether (described under 

 the first head) is analogous to the formation of trinitrophenylenedi- 

 malonic ester from the bromtrinitrophenylraalonic ester,* since in the 

 corresponding dinitro compounds the third atom of bromine cannot 

 be replaced by the phenoxy (see second head) or malonic ester 

 radical, as the case may be, even under more powerful inducements 

 than are needed to bring about this action with the trinitro com- 

 pounds, thus furnishing another example of the loosening effect of 

 the presence of a third nitro group upon the bromine. The stability 

 of the third atom of bromine in the dinitro compound, so far as re- 

 placement by an alcoholate radical is concerned, mentioned under 

 the second head, is analogous to that of the third bromine atom in 

 dinitrobromphenylmalonic| or acetaceticj ester in the corresponding 



* These Proceedings, xxiv. 208. t Ibid., 2. % Ibid., 274. 



