574 



Mil. F. E. SMITH, MR. T. MATHER, AND DR. T. M. LOWKY 

 TABLE IX. Rayleigh Form of Voltameter. 



with those obtained with 075 and 0'25 ampere. In this case a resistance was added 

 to that portion of the branch circuit containing C for one-half of the time of the 

 experiment and to B for the other half. A current of 1 ampere was passed through 

 A and D, and through B and C currents of 075 and 0'25 ampere passed. The total 

 mass of silver deposited in A and D was 14 "022 15 grammes and in B and C it was 

 14'02246 grammes, a difference of 0'002 2 per cent. (62a, b, c, d). 



Effects of Electrolysis on the Concentration of the Electrolyte. 



When the current first leaves the anode it spreads out in the approximately 

 homogeneous electrolyte which surrounds it, and, if the normal distance from the 

 anode to the kathode is everywhere the same, the current density over the anode 

 surface is uniform, and the same is true for the kathode surface. Immediately, the 

 layers of liquid in contact with each electrode become changed in concentration and 

 density : around the silver anode a film of dense liquid of high concentration is 

 formed and about the kathode a film results the density of which approximates to 

 that of water and is of very small concentration. In the Rayleigh form of voltameter 

 the heavy anode liquid descends, and since it constitutes a path of high conductivity, 

 more silver per unit area is deposited on the base of the bowl than on the sides if the 

 anode surface is everywhere at the same normal distance from the kathode surface. 

 This descending column of heavy anode liquid gives rise to the star-shaped deposit on 

 the base of the bowl which has been so frequently noticed by other observers and by 

 ourselves (fig. 8, Plate 9). If the distance of the anode from the base of the bowl is 

 appreciably greater than the distance from the sides, the path of least resistance is 

 not necessarily that of the descending column, and the deposit per unit area on the 

 base is less than on portions of the sides. This latter condition holds for the Rayleigh 

 voltameter as we have generally used it. 



It follows that the lowest point of the anode is in contact with a thin layer of 

 electrolyte of greater concentration than the solution at the surface. A concentration 

 cell is thus produced and normally a current would flow through the electrolyte from 



