Forces between Atoms and Chemical Affinity. 

 while naphthalene can be represented as 



785 



This formula, like that for benzene, is quite symmetrical, 

 and all the affinities are provided for. 



The difference between the theory we are considering and 

 the accepted theory of valency may be expressed by saying 

 that not only is every possible valency compound on the old 

 theory a valency compound on this theory, but every com- 

 pound which would be a valency one on the old theory if 

 the valency of every element was doubled, i. e. if hvdroo-en 

 were regarded as a dyad, oxygen as a tetrad, nitrogen as 

 hexad, and so on, would be a valency compound on the new, 

 with the atoms retaining their original valency. This only 

 applies to the compounds when the atoms are uncharged ; 

 when the atoms are charged the valency conditions are, as 

 we shall see, the same as on the old theory. 



The distribution of electricity on the atoms in the cases 

 we have been considering, corresponds to tubes of force going 

 from a corpuscle near the surface of one atom to the core of 

 another. It corresponds, for the case of two atoms each 

 containing a single corpuscle, say two atoms of hydrogen, 

 to that represented diagrammatically in fig. 2. We see that 

 in this case the shortest distance between oppositely charo-ed 

 particles is considerably greater than the minimum distance 



