OF ARTS AND SCIENCES. 



249 



time to explain the reactions by which it was formed, an objection 

 which is removed by this paper. The easy conversion of a substance 

 having Formula I. into a toluol compound is to be expected, whereas 

 with one having Formula II. it would be necessary to add two atoms 

 of hydrogen, an action which could hardly take place quantitatively 

 by boiling with dilute sulphuric acid, or distillation with steam, the 

 two processes employed in converting the bromdinitrophenylmalonic 

 ester into the bromdinitrotoluol. This formation of the substituted 

 toluol therefore establishes Formula I. beyond question. 



In the second place, the way is opened to the determination of the 

 position of the substituting radicals upon the benzol ring in all these 

 compounds, as their position must be the same as in the bromdinitro- 

 toluol. Messrs. W. B. Bentley and W. H. Warren have accordingly, 

 at our request, determined the constitution of the bromdiuitrotoluol by 

 replacing its bromine successively by the amido group and by hydro- 

 gen, and have found in this way that its constitution is 



CH 3 . Br . NO a . N0 2 .1.3.4.6. 



For the details of their work we would refer to their paper, which fol- 

 lows immediately after this. It follows from this that in the tribrom- 

 dinitrobenzol Br . H . Br . N0. 2 . Br . N0 2 . 1 . 2 . 3 . 4 . 5 . 6, the bromine 

 numbered 1, which stands in the ortho position to one nitro group and 

 the hydrogen, in the para position to the other nitro group, has been 

 replaced by the malonic ester radical CH(COOC 2 H 5 ) 2 ; that the bro- 

 mine replaced by hydrogen is the one between the two nitro groups ; 

 and that the third bromine, which is in exactly the same relation to 

 the nitro groups as the one replaced by the malonic ester radical, is 

 left entirely unaltered. This last fact seems very strange to us. The 

 constitution of our bromdinitrophenylmalonic ester is therefore repre- 

 sented by the following graphical formula : — 



CH(COOC 2 H 5 ) 2 



