528 Constitution of the Diazoamido- Compounds, 



All these formulae are, however, more or less open to objec- 

 tion, and need not be further discussed at present. It will 

 suffice to mention that No. III., which at first sight might 

 appear the most probable of the three, is incapable of repre- 

 senting such compounds as diazobenzenedimethylamide. 



The views now advanced concerning the constitution of this 

 interesting group of compounds open up suggestive lines of 

 investigation in the direction of isomerism as connected with 

 position. In the formula representing phenyl as a triad 

 radical previously given, the free bonds have been represented 

 in the para-position, because the ortho-quinone of the benzene 

 series does not appear to be capable of existence. But the 

 formula obviously allows the possibility of such an ortho- 

 arrangement :■ — 



H 

 C= C— 



/\ /\ 



HC C= HC 0= 



II I II I 



HC CH HC CH 



c c 



H H 



The para-position of the substitnents is, however, in har- 

 mony with the known behaviour of diazoamidobenzene, the 

 isomeric amidoazobenzene having its substitnents in the para- 

 position. It seems probable, therefore, if there is anything 

 in the previously expressed view concerning this isomeric 

 transformation, that at least in this diazoamido-compound 

 the substituents — N : N — and =NH= are in the para- 

 position. 



Summing up the general results of the present discussion, 

 it appears to me that the formula now proposed for the mixed 

 diazoamido-compounds is the only one that has hitherto been 

 in harmony with all the known characters of these compounds, 

 and as such it is at any rate worthy of serious consideration 

 by chemists. Analogy leads to the belief that the normal 

 compounds have a similar, or at least a partly similar con- 

 stitution ; but the evidence is not so satisfactory in these 

 cases, owing to the similarity of the two halves of the mole- 

 cule, which renders it impossible to follow the course of 

 decomposition with the same certainty as in the mixed com- 

 pounds. Before, however, the w 7 hole question of the consti- 

 tution of the diazoamido-compounds can be completely worked 

 out on the lines here suggested, it will be necessary to have a 



