﻿Organic Substances and the Electron Theory* 199 



The asymmetrical case o£ the above is undeveloped, but 

 it is fair to assume an interpretation similar to the above, 

 viz., the thrusting apart of the bands due to the con- 

 stituent groups. 



Fie. 1. Fiar. 2. 



B , 



There are many substances of the above type, e. g. f 

 diketones 19 , dioleflnes 6 , and unsaturated ketones 20 , but 

 in no case has ihe investigation covered the whole region 

 in which bands should occur. The results obtained in the 

 regions examined do, however, correspond accurately with 

 this theory. 



The importance of § § III.— IV. lies in the fact that we can- 

 not in most cases deal with isolated centres in practical work, 

 since even when they can exist their bands are usually out- 

 side the ordinary regions. We have therefore to investigate 

 the influence of groups and calculate from them the constants 

 for the free centres. Also, as stated above, even the simple 

 bands in reality are made up of fine lines ; it is of importance 

 to show cause why these should move together. The above 

 reasoning, while by no means conclusive, suggests that this 

 will be the case and no exceptions have been met with in 

 practice. 



V. The Benzene System. 



This consists of six identical vibration centres arranged in 

 accordance with the laws of isomerism, in a ring or 

 otherwise. 



The coefficients of induction are : 



self-induction I ; 



mutual induction between ortho carbons m Q 



meta .. m,„ 

 para ., >n p . 



