488 



Mr. W. Coldridge on the Electrical and 



The idea of examining the influence of these liquids pro- 

 ceeded from a study of Moissan's* work on liquid hydrofluoric 

 acid ; it seemed that the conductivity he developed was due 

 to such an interchange as : — 



r 



HP | + 



r 



"~ ^ 



t \ r 



IKFjl 



HF | 



) 



ThfI 



y p y 



and it was conceived that if a similar condition of dynamical 

 stability could be produced in stannic chloride, conductivity 

 would be developed. The results have justified the induction. 

 The delicate observations made by Kohlrausch on the resist- 

 ance of pure water, and the effect of exposing it to the atmo- 

 sphere of a room charged with tobacco-smoke, are explicable 

 on the same lines ; the water would absorb traces of carbonic 

 acid and of the basic products, which in turn would form 

 hydrates, and then there would result a similar condition of 

 interchange. 



The generalization may now be provisionally stated : — that 

 such an antecedent condition of dynamical equilibrium is 

 absolutely essential to the development of the power of elec- 

 trolytic conductivity. With no great difficulty, it would be 

 possible in terms of 



(1) the number of such interchanges per unit of time, 



(2) the degree to which the stability of the original unelec- 



trolysable molecule is disturbed by each interchange, 



to establish a dynamical theory to explain the influence of 

 (a) the concentration, (b) the temperature, on the conductivity 

 of electrolytes; and for this purpose would be needed accurate 

 measurements of the resistance of solutions (say, of the tetra- 

 chloride in alcohol, in ether, and of their temperature-coefn- 

 cients). The results would emphasize the great value of some 

 dynamical explanation of chemical action, and the influence 

 of mass and temperature on its course. 

 The differences observed in the action of 



(1) dry sulphuretted hydrogen on stannic chloride, 



(2) dry sulphuretted hydrogen on stannic chloride in chlo- 



roform solution, 



(3) dry sulphuretted hydrogen and stannic chloride on water, 



(4) absolute alcohol on sulphuretted hydrogen and stannic 



chloride, 



(5) dry sulphuretted hydrogen on ether and stannic chloride, 



* An account of Moissan's work is given in ' Nature/ vol. xxxvii. 

 (1887-8) ; Moissan considers the potassium fluoride to be the electrolyte. 



