178 PROCEEDINGS OF THE AMERICAN ACADEMY 



benzol ; very slightly in ether or carbonic disulphide ; insoluble in 

 ligroine. The best solvent for it is acetone or glacial acetic acid, 

 as it is more soluble in these liquids tlian in any other ; but its slight 

 solubility in all the common solvents is one of its most striking 

 properties. 



Dinitroresorcine Dimethylether, CgH2(CH30)2(N02)2. 



This substance was formed in addition to the bromdinitroresorcine 

 dimethylether by the action of sodic methylate in methyl alcoholic 

 solution upon tribromdinitrobenzol, whether the substances were 

 heated together, or the action was allowed to take place in the cold. 

 The action of sodic methylate, therefore, on account of this indiffer- 

 ence to the effect of temperature, is unlike that of sodic ethylate, 

 which gave only bromdinitroresorcine diethylether in the cold, and 

 when heated only dinitroresorcine diethylether. The dinitroresorcine 

 dimethylether, which was formed in comparatively small quantity, was 

 obtained from the alcoholic washings and mother liquors of the sub- 

 stance melting at 237°-238°. The residue left after the evaporation 

 of the alcohol was a viscous mass, which contained in addition to the 

 substance of which we were in search an oily impurity similar to that 

 obtained from the ethyl compound and a little bromdinitroresorcine 

 dimethylether. It was therefore a matter of some difficulty to isolate 

 a pure substance from it, but we finally succeeded by repeated crystal- 

 lization from hot alcohol, during which crystals of two sorts were 

 obtained, one consisting of white needles turning brown in the air, 

 the other of lemon-yellow rhombic crystals, which appeared especially 

 during the earlier parts of the crystallization, and were gradually con- 

 verted into the white needles. That the difference between the two 

 forms consisted in the presence of one molecule of alcohol of crystalli- 

 zation in the white needles was shown by the following analytical 

 results : — 



I. 0.9817 gr. of the air-dried substance lost 0.0177 gr. at 100°. 

 II. 0.7617 gr. of the substance dried in vacuo lost 0.0142 gr. at 100°. 



Alcohol 



These numbers agree somewhat better with the percentages calcu- 

 lated for three molecules of water of crystallization ; but, apart from 

 the improbability that the substance would take up water when crys- 

 tallized from ordinary alcohol, we have found that the liquid given 



