280 MAJOR A. E. OXLEY ON THE INFLUENCE OF MOLECULAR 



may be considered as containing respectively 



4w + 2, 4 2, 4w 6 magnetons. 



Moreover, PASCAL has shown that the magnitude of xcn a is quite independent of the 

 presence of nitrogen, oxygen, or sulphur in the compound, so that, where the additive 

 law holds for such complex molecules, it will hold for the whole series of additive 

 compounds formed with the group. 



PASCAL also investigated the halogens, fluorine, chlorine, bromine and iodine. The 

 atomic susceptibilities of these elements, as deduced from the molecular susceptibilities 

 of organic compounds in which they are contained, are given in column 2, the 

 approximate number of magnetons per atom is given in column 3. 



It must be admitted, however, that these last four results do not warrant an 

 extension of the magneton theory to these elements. Moreover, although the results 

 for the hydrocarbons mentioned above are very suggestive, yet there remain 

 difficulties, such for example as the values of X, which for the benzene ring is 

 equal to -15xlO~ 7 , the interpretation of which does not fall into line with 

 the magneton view. Further difficulties are met with in the cases of nitrogen and 

 oxygen. 



Perhaps these difficulties should be expected, since it has been proved that the 

 additive law breaks down for many atoms, especially as regards the metallic elements. 

 When, in addition, we take into consideration that the mutual disturbances of the 

 electron orbits, in atoms containing a relatively large number of electrons, have been 

 neglected, the agreement is probably as good as could be expected. Thus in the case 

 of the hydrocarbons considered above, compounds which show no electrolytic 

 dissociation and in the formation of which no transfer of electrons takes place from 

 one atom to another on combination, we might expect that the addition of a 

 hydrogen atom or a CH a group would add a definite amount of diamagnetism 

 to the compound. But in the case of the metals and some other elements, chemical 

 combination may be accompanied by the transference of electrons, i.e., by a break- 

 down of the magnetic elements of the atoms. In such cases the additive law could 

 not hold. 



