OF ARTS AND SCIENCES. 297 



bromide. In most cases, between 80 and 90 per cent of the tribrom- 

 trinitrobenzol used is accounted for by the amounts of inorganic 

 salts formed. The experimental work is not accurate enough to 

 allow a more careful discussion of this part of the subject, as not 

 enough attention was paid to various details, such, for instance, as 

 maintaining a constant temperature, and measuring accurately the 

 amounts of solvent used. 



In all the experiments with benzol given in Table II. free alco- 

 hol was also present. To determine what influence this had on the 

 reaction, we made another experiment, in which all free alcohol was 

 carefully excluded, so that in this case benzol was the only liquid 

 present. 



XI. Weight taken, 5.0453 gr. Weight of the aqueous solution, 

 83.4 gr. ; 19.6 gr. of the solution gave 23.8 c. c. of nitrogen at a 

 temperature of 28°. 5 and a pressure of 760.1 mm. ; 43.4 gr. of the 

 solution gave 1.9610 gr. of argentic bromide and 1.55 gr. of the di- 

 ethylether of trinitrophloroglucine. The organic matter insoluble 

 in water weighed 2.75 gr. 



From these results 35.34 per cent of nitrogen and 59.62 per 

 cent of bromine are obtained. The percentage of nitrogen, when 

 benzol and alcohol were used- as the solvents, averaged 33.49, so 

 that this experiment shows that the presence of alcohol does not 

 materially affect the result. The somewhat high percentage of 

 nitrogen in this experiment may be due to the fact that the mix- 

 ture stood two days instead of the usual twelve hours. This subject 

 of the effect of time on the action will be discussed later in the 

 paper. 



We have also made two quantitative determinations, in which 

 acetic ester was used with a little alcohol as the solvent. 



XII. Weight taken, 1.0412 gr. Weight of the aqueous solution, 

 58 gr. ; 17.5 gr. of the solution gave 0.63 c.c. of nitrogen at a tem- 

 perature of 23°. 5 and a pressure of 758.9 mm.; 40.5 gr. of the 

 solution gave 0.4504 gr. of argentic bromide. 



XIII. Weight taken, 1.0271 gr. Weight of the aqueous solu- 

 tion, 49.1 gr. ; 18 gr. of the solution gave 2.8 c.c. of nitrogen at a 

 temperature of 22°. 5 and a pressure of 760.8 mm. ; 31.1 gr. of the 

 solution gave 0.4902 gr. of argentic bromide. 



