OF ARTS AND SCIENCES. 299 



0.78 gr.* of C 6 (OH) 3 (N0 2 ) 3 , corresponding to 1.03 gr. of the tri- 

 ethylether, making the total yield of the triethylether 6.29 gr. 



Experiments VI. and VII. — Benzol present, 20.21 gr. of tri- 

 bromtrinitrobenzol gave 10.50 gr. of organic matter insoluble in 

 water from which were obtained 3.25 gr. of C 6 Br 3 N0 2 (OC 2 H 5 ) 2 , 

 1.36 gr. of C 6 (OC 2 H 5 ) 3 (lSr02)3, and somewhat less than 6 gr. of 

 the semi-liquid fraction from the mother liquors. From the aque- 

 ous solution were obtained 4.53 gr. of C 6 OH(OC 2 H 5 ) 2 (lSr0 2 ) 3 , 

 corresponding to 4.93 gr. of the triethylether, and 0.88 gr.* of 

 C 6 (OH) 3 (iSl"02) 3 , corresponding to 1.16 gr. of the triethylether, 

 making the total yield of the triethylether 7.45 gr. 



These results confirm the inference drawn from the percentage, 

 of sodic nitrite and bromide, that the presence of benzol is unfavor- 

 able to the reaction hj which sodic nitrite is formed, but promotes 

 that which yields sodic bromide; a fact which is shown more plainly 

 by this collection of the results in tabular form. 



C 6 (OC 2 H 5 ) 3 (N0 2 ) 3 . C 6 Br 3 N0 2 (0C 2 H s ) 2 



Alcohol alone (I. and II.) 6.29 gr. 5.11f 



Benzol and alcohol (VI. and VII.) 7.45 gr. 3.25f 



All our results, therefore, show that the presence of benzol is fa- 

 vorable to the elimination of bromine, unfavorable to that of nitro 

 groups. The most probable theoretical explanation of this obser- 

 vation which has occurred to us depends on the effect of the change 

 of solvents upon the amounts of the salts precipitated, hut any dis- 

 cussion of this theory at present would not be worth while, because 

 the principle on which it rests has not been tested by experiment 

 so far as we can find. 



We have not succeeded in finding the cause of the very marked 

 variations in the amounts of sodic bromide shown in Tables I. and 

 II. At first we feared they might be due to defects in our experi- 

 mental work, but that this is not the case is shown by the following 

 comparison of the weights of trinitrophloroglucine triethylether 

 actually found with the amounts of this substance calculated from 

 the percentages of bromine eliminated as sodic bromide in the same 

 experiment. We have selected this body for the comparison, be- 



* These numbers are only estimates, as the amounts of trinitrophloroglucine 

 were determined only in Nos I. and VI., the weight found being doubled to give 

 the numbers. It is to be remembered also that our method for determining 

 the trinitrophloroglucine was far from satisfactory. 



t These numbers are only approximations to the true yields. 



