234 PROCEEDINGS OF THE AMERICAN ACADEMY. 



I. 0.2384 gram of the substance gave 25.1 c.c. of nitrogen at a temper- 

 ature of 25° and a pressure of 753.3 mm. 

 II. 0.2887 gram of the substance gave by the method of Carius 0.2910 

 gram of argentic bromide. 



Calculated for Found. 



C„HBr,(N0j)3. I. II. 



Nitrogen 11.36 11.65 



Bromine 43.10 42.89 



The substance is, therefore, dibromtrinitrobenzol (Brg 1. 3.(NOo)32. 4. 6), 

 formed by the replacement of one atom of bromine in the tribromtrini- 

 trobenzol by Iiydrogen, and tlie sodic sulphite has behaved like a reduc- 

 ing agent in this case just as it did with the tribromdinitrobenzol. 



Properties of Metadibrom-s-trinitrohenzol. — It crystallizes from ben- 

 zol — or better, a mixture of benzol and ligroin — in broad prisms termi- 

 nated by two planes at a slightly acute angle to each other, or in slender, 

 blunt-ended prisms, or in rhombic crystals. It has a pale yellow color with 

 a slight greenish tinge, and melts at 135°. It is freely soluble in benzol 

 or ether ; soluble in chloroform, acetone, or cold alcohol, freely soluble 

 in hot alcohol ; slightly soluble in hot ligroin ; insoluble in water. The 

 best solvent for it is a mixture of alcohol and benzol, or of benzol and 

 ligroin ; strong hydrochloric or sulphuric acid has no action on it, either 

 hot or cold. Strong nitric acid does not dissolve it in the cold, but 

 forms a yellow solution with it when hot, which deposits the unaltered 

 substance on cooling. Sodic hydrate solution gives a pale yellow solu- 

 tion when liot ; no perceptible action when cold. Alcoholic sodic 

 hydrate gives a deep red color. 



The aqueous wash waters obtained in the preparation of dibromtri- 

 nitrobenzol by this process, although showing a strong red color, con- 

 tained so little organic matter that we did not succeed in isolating any 

 new compound from them. The residue left on evaporating them 

 consisted chiefly of sodic bromide and unaltered sodic sulphite. 



Preparation of Dihromtrinitrohenzol from Dibromdinitrohenzol. 



In the hope of finding an easier method of preparing the dibromtrini- 

 trobenzol we next tried to make it from dibromdinitrohenzol. The 

 dibromdinitrohenzol was made by the method of Jackson and Cohoe, * 

 which, however, we modified somewhat in converting the bromacetanilid 



* These Proceedings, XXXVI. 77. 



