236 PROCEEDINGS OF THE AMERICAN ACADEMY. 



I. 0.2 tm of substance gave according to the method of Carius 



0.4138 gram of argentic bromide. 

 II. 0.2987 gram of substance gave 0.4150 gram of argentic bromide. 



Bromine 



The substance is, therefore, a tribromdinitrobenzol) and its appearance 



i> not unexpected, since J. F. Wing and one of us* found that tetra- 

 bromdinitrobenzol was always formed during the preparation of tribrom- 

 triuitrobeuzol from tribromdinitrobenzol. There can be no doubt about 

 the constitution of this tribromdinitrobenzol, because it is made from the 

 dibromdinitrobenzol (Br a 1. 3. (N0 8 ) 2 4. 6) by the introduction of an 

 atom of bromine, wbicb can enter only in two places, — between the 

 nitro groups, or between tbe atoms of bromine. If tbe substitution 

 takes place between the nitro groups, there must be formed symmetrical 

 tribromdinitrobenzol, which melts at TJ2 3 ; there is left, therefore, for 

 our substance melting at 150° only the constitution Br 3 1. 2.3. (NO s ) a 4.6. 

 Properties of the 1.2.3. Trihrom- 4. 6. dinitrobenzol. — Yellowish 

 white rectangular plates bevelled on tbe sides, when crystallized from a 

 mixture of alcohol and benzol. Melting point 150°. It is freely 

 soluble in benzol, or ether; soluble in chloroform, glacial acetic acid, or 

 ;oue; soluble in cold alcohol, freely soluble in hot alcohol; slightly 

 soluble in cold ligroin, soluble in hot ; insoluble in water. The best 

 solvent for it is a mixture of alcohol and benzol. Strong hydrochloric 

 or sulphuric acid gives no visible action hot or cold. Strong nitric acid 

 appears not to act in the cold, but dissolves it when hot, depositing the 

 unaltered substance as it cools. A solution of sodic hydrate does not 

 act on it apparently either hot or cold, but in presence of alcohol gives a 

 light yellow color. 



Action of Sudir Ethylate >>n Dibromtrinitrobenzol. 



L.5 grams <>f dibromtrinitrobenzol (Br a 1.3.(NO s 2.4.6) were 

 lived in 1 •"» c.c. of benzol, and mixed with sodic ethylate in the pro- 

 portion of three molecules of the ethylate to each molecule of the dibrom 

 compound. The Bodic ethylate was prepared by adding the calculated 

 niit of sodium to •'!" c.c. of absolute alcohol. The liquid .-it once 

 took on an intense red color, and became turbid. To make sure of com- 

 pleting the reaction tbe mixture was allowed to stand for twelve hours al 



ordinary temperature in a cork flask, alter which it was lillered, and the 



• These Proceedings, Will. 1:39. 



