464 Mr. S. S. Richardson on Magnetic Rotary 



liquids * we may calculate the number of electrons of longest 

 period in terms of rj and (l + £), since 



Neglecting f, we obtain: — 



Water PiVi 2 = '296, m. Xylene ... p l 7j ] 2 = l'176, 



Benzene... p 1 rji 2 = l'03S, Naph. brom. .. p 1 r) 1 2 = *625. 



As \i enters to the fourth power, a small error in its value 

 will considerably affect the result. 



The above numerical results may now be reviewed in con- 

 nexion with the electronic theory of valency. According to 

 the electrostatic theory of J. J. Thomson and Ramsay, the 

 force of chemical affinity is produced by the transference 

 of a negative electron from one atom to another ; in that of 

 Stark the electron is attached to neither atom but exerts 

 an attraction on both ; whilst in the hypothesis recently put 

 forward by Arsem f, the particle is in a state of continual 

 oscillation from one atom to the other. Without, however, 

 formulating any hypothesis as to the mechanism by which 

 the electron sets up the force of chemical affinity, whether 

 electrostatic or electromagnetic, we may conclude that only 

 one electron is concerned in the production of each " bond " 

 of affinity ; and the theory of J. J. Thomson and Ramsay 

 may be used as the most convenient way of distinguishing 

 between these electrons and others associated with the atom. 

 Remembering that the molecule as a whole is neutral and com- 

 mencing with the atoms of which it is composed assembled 

 in their neutral state, it is clear that the number of electrons 

 to be transferred is equal to the number of active positive 

 valencies in the molecule. Now according to the theory of 

 Abegg t, these will represent either normal or contra- 

 valencies according to the group of the periodic system in 

 which the element falls. Thus, for example, we have : 



Group 1234567 



Element ... Na Mg Al Si P S CI A 

 + Valency... +1 +2 +3 +4 +5 +6 + 7 



V „ /"v» 



v v~ 



Normal. Contr 



a. 



* In the tables given in Part I. for naphthalene bromide and carbon 

 bisulphide, the values given under I are those of wS. 



f Jour. Amer. Chem. Soc. (36) pp. 1655-1675 (Aug. 1914). 

 I Zeit. anorg. Chem. (39) p. 330 (1904). 



