Quantivalence of Oxygen. 409 



The last compound then reacts with the residue, :N . C 6 H 5 to 

 form carbanilainidonaphthol : — 



CioH/ n C.SH+:N.C 6 H, = C 10 h/ X C . NH . C 6 H 5 + S 



N N / X N' 



This result is considered by Jacobson to indicate the presence 

 of hydroxy 1 in the azo-naphthol compound ; but the evidence 

 is not so satisfactory as could be desired, because the reaction 

 takes place only at a high temperature (250°) in a sealed 

 tube. 



The most recent experimental evidence thus, on the whole, 

 appears to favour a reversion to the old ^iew of the constitution 

 of the two groups of compounds ; but the non -phenolic 

 character of the azo-naphthol /3-derivatives and the other 

 differences pointed out are certainly not explained by the old 

 formulae. 



In order to express the constitution of the azo-/3-naphthyl- 

 amine compounds by a formula which meets all the require- 

 ments of the case, I have been led to the conclusion that the 

 azo- and NH 2 -groups, being in the ortho-position, interact 

 with the formation of a closed chain of nitrogen atoms : — 



— N=N— X __^_N— X 



— NH 2 ~X 



W X H 



The formula of benzeneazo-/3-naphthylamine would, on this 

 view, be written : — 



N 



c 10 h 6 (|)n.c 6 h 5 



X 



W X H 



That this formula is in harmony with the known properties of 

 the substance will appear from the following considerations: — 

 The difficulty with which the compound forms salts may be 

 explained by supposing that acids have first to break up the 

 nitrogen ring, i. e., 



|>.C 6 H 5 , -*% 



_\ into N.C 6 H 5 



H /\ H — NH 2 . HC1 



The same explanation may hold good with respect to the 



