486 Mr. W. Coldridge on the Electrical and 



function of the chemical stability. Indeed the problem of 

 electrolysis is at its foundation a chemical one; but at this, its 

 foundation, the chemical problem resolves itself into an ante- 

 rior physical one, namely the laws that govern the interaction, 

 the attraction of atoms at atomic distances. " The scientific 

 aim of the theory of electrolysis has been stated by F. Kohl- 

 rausch to consist in the reference of electrochemical phenomena 

 to mechanical or electromechanical laws " * : herein must be 

 the solution of the problem of chemical affinity. 



To the question whether there is some physical property 

 of pure water, pure hydrochloric acid, hydrofluoric acid, &c. 

 which endows them with insulating-power, and the absence or 

 difference of degree of which in fused salts admits of conduc- 

 tivity no successful answer has been given, though a great 

 variety of attempts have been made. Doubtless viscosity is 

 a factor in the result, and Faraday's law of liquido-conduction 

 is a statement of that fact. But the influence of viscosity is 

 secondary rather than primary : all the electrolytes must have 

 a degree of limpidity, and as the limpidity decreases so will 

 the resistance increase. As examples, Kohlrausch's experi- 

 ments on Silver Iodide f, Arrhenius's investigations of the 

 actions of Fluidity on the Conductivity of Electrolytes J : 

 though these would have been improved by the use, as sole 

 solvent, of some oily polyhydric alcohol. But limpidity, as is 

 seen in the various nonconducting pure liquids, does not 

 involve electrolysability. The destruction of the physical 

 homogeneity, and generally the change of physical properties 

 which must occur when stannic chloride is heated from 16° C. 

 to 112° C, its boiling-point, has not apparently any influence, 

 and certainly not within the limits of delicacy of my experi- 

 ments, on its nonconductivity. 



To sum up : It has been advanced that the fact that stannic 

 chloride is homogeneous, chemically homogeneous, accounts 

 for its nonconductivity : similarly for the other nonelectro- 

 lytes. To continue : It will be demonstrated how the results 

 obtained show that where this chemical homogeneity is de- 

 stroyed, where the whole or part of the stannic chloride enters 

 into combination so that molecular interchanges, akin to those 

 which Williamson so vividly portrayed in his epoch-making 

 papers on the Theory of Etherification, can occur, then the 

 power of electrolytic conductivity is developed. The validity 

 of this conclusion will be most cogently established by answer- 



* Keport on the Present State of our Knowledge in Electrolysis and in 

 Electrochemistry. W. IN. Shaw, M.A. (Brit. Assoc. 1889). 

 t -Fogg. Ann. 1876, p. 159. 

 \ Kongl. Vetenskaps-Akad. Fordhandlingar, 1885. 



