THE ELECTROLYTIC DISSOCIATION THEORY 399 



that many of the supporters of the electrolytic dissociation 

 theory will be disposed to quarrel. 



In conclusion, the question as to the motive for electrolytic 

 dissociation — the mechanism of the process — may be referred to. 

 We have seen that the ions show very great differences in their 

 affinity for electricity, and it seems plausible to suppose that this 

 is one of the factors conditioning ionisation. It is, however, 

 impossible to carry this idea through quantitatively, as Abegg 

 and Bodlander have pointed out, 1 since salts in which the ions 

 have comparatively small electro-affinity are almost as highly 

 dissociated as those in which the affinity is very much greater. 

 These observers therefore suggest that the molecule first de- 

 composes into neutral atoms, which then take up the electric 

 charges, so that the degree of ionisation also depends on the 

 strength of the bond between the individual atoms. This 

 " separation into neutral atoms " seems quite as difficult to 

 account for as the original question at issue, and as we know 

 so little of chemical affinity, which may itself be electrical in 

 nature, nothing definite can be said with regard to it. Werner 2 

 and Lowry 3 lay stress on another aspect of the question; they 

 consider that ionisation is brought about by the affinity of the 

 solvent for the components of the solute molecule. In this case 

 also chemical affinity between the components of the molecule 

 might be supposed to counteract the ionising tendency of the 

 solution. This suggestion as to the part played by the solvent 

 seems plausible, since, as we have already seen, the best ionising 

 solvents are those having "subsidiary valencies," 4 and it is 

 natural to suppose that these are effective by entering into 

 chemical combination with the solute. There would thus seem 

 to be at least three factors of importance for ionisation : (1) the 

 chemical affinity between solvent and solute ; (2) the chemical 

 affinity between the components of the solute molecule ; (3) the 

 affinity of the components of the solute molecule for electricity. 

 As to the relative importance of these three factors, practically 

 nothing can be said in the present state of our knowledge. 



1 Loc. cit. p. 463. Cp. also Abegg, Zeit. anorg. Chem. 1904, 39, 330. 



* Zeit. anorg. Chem. 1893, 3, 294. 



3 Trans. Faraday Society, 1905, 1, 197. 



* Briihl, loc. cit. 



