Quantivalence of Oxyyen. 411 



This view of their constitution is at once negatived by the 

 fact that the azo-derivatives of /3-naphthylamine all give a/5- 

 naphthvlene-diamine on reduction. This last property is, it 

 is hardly necessary to say, expressed by the formula now 

 proposed. 



Granting the probability of the latter, and, as has been shown, 

 there is much to commend it to consideration, the analogy 

 between the /3-naphthylamine and ^-naphthol derivatives, 

 which has already been indicated, points to a similar constitu- 

 tion for the latter. I have no hesitation in proposing this 

 modification of the generally received formula, although it 

 will hardly find favour as yet with many chemists because it 

 involves the existence in these compounds of tetravalent 

 oxv£en : — 



N 



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



H 



There is no doubt, however, that the time is rapidly ap- 

 proaching when, in the opinion of the majority of workers, 

 we shall have to give greater latitude to our notions of valency, 

 both for elementary atoms and compound radicals. Without 

 attempting here to discuss the general question, I may, how- 

 ever, point out that the higher valency of oxygen is only in 

 accordance with what might be expected when we consider 

 that in the periodic system this element is classed in a family 

 of which the higher members are hexavalent*. In the way 

 of direct evidence that oxygen may be tetravalent, we have 

 Friedel's compound formed by the combination of hydrogen 

 chloride with dimethyl oxide f : — 



CH 3 / U \C1 or CH 3 / U — U1 n 



All the facts and arguments in favour of the higher valency 

 of oxygen have been recently brought together in two papers 

 published by Mr. J. F. Heyes %. If this tetravalent function 

 be conceded to oxygen, the properties of the azo-/3-naphthol 

 compounds become easily explicable. 



The first points requiring explanation from the present 

 point of view are the identity of phenylhydrazone-a-naphtha- 

 quinone with benzeneazo-a-naphthol, and the non-identity 

 of phenylhydrazone-/3-naphthaquinone with benzeneazo-/3- 



* See Lothar Meyer's ' Modern Theories/ Engl. ed. p. 342. 

 t Wurtz's ' Atomic Theory/ Int. Sci. Ser. p. 231. 

 X Phil. Mag. 1888, vol. xiv. pp. 221 & 207. 



