Electrification at Liquid- Gas Surfaces. 297 



cc w" therefrom. This may be repeated for say another two 

 temperatures, and thus the variation of "log A" and " n " 

 with temperature can be ascertained. The formula may then 

 be completed. 



One reason for the diminution of "n" with temperature 

 may be stated as follows. At the higher temperatures the 

 fluidity of the solvent is increased. Now the behaviour of 

 the solute is found to be in many ways analogous to that of a 

 gas. This analogy Would apparently become more pronounced 

 the higher the temperature, i. e. the greater the fluidity of 

 the solvent, for then the particles of solute could move about 

 with greater freedom. The viscosity of a gas is known to be 

 independent of density, and on glancing at figs. 6 and 8 we 

 see that the higher the temperature the less pronounced 

 becomes the increase of viscosity due to the increase of 

 density. This is specially evident in the case of sodium 

 chloride at 100° C. 



It may be of interest to note here that the same method 

 of plotting was used to determine if F (/j.) in the formula 



F(/x) — a— j 



was of the form (fi) n in the cases of water and mercury c It 

 was found not to be so, so that some other form must be 

 ascribed to this function in the case of these two substances 

 at least. 



In conclusion, I desire to express my thanks to Professor 

 Gibson for the encouragement he gave me during the course 

 of the work. 



XXXIII. Tlie Electrification at Liquid-Gas Surfaces. By 

 H. A. M c Taggart, M.A. Toronto; Research Student of 

 Gonville and Caius College, Cambridge *. 



WHEN a liquid in the form of drops falls through a gas 

 and splashes against an obstacle it is found to be 

 electrified. At the same time the gas acquires a charge of 

 the opposite sign. This charge found on the liquid varies 

 with the liquid, the gas through which it falls, the nature of 

 the obstacle on which it strikes, and the force of the impact. 

 To account for this electrification it is usually supposed that 

 at the surface of separation between the liquid and the gas. 

 a double layer is formed, the two surfaces of which arc 



* Communicated bv Prof. Sir J, J. Thomson, O.M.. F.R.S. 



