I90I Steele] ABSTRACT $1 



with each other, and the two solutions are placed in a U-tube 

 so that there is a layer of the lighter solution in both arms sur- 

 rounding the electrodes while the heavier fills the bottom of the 

 tube. If now an electrochemical equivalent of current be sent 

 throuiih, there will have occurred in the one meniscus an 

 increase of concentration, in the other a decrease, both equal 

 to the difference in migration value in the two solvents. This 

 accumulation in the boundary is divided between the surface 

 layers of the two liquids in the relation of the distribution ratio 

 (Verteilungscoefficient), and is removed from them in propor- 

 tion to the rates of diffusion in the two solvents. Hence in a 

 favorable case where the product of the distribution ratio and 

 the square root of the ratio of the rates of diffusion is large, 

 practically all the accumulated electrolyte goes into the elec- 

 trode solution. Hence from analysis of the electrode solution 

 before and after electrolysis we may measure the migration 

 value in the solvent in the middle of the tube. The fact that 

 with potassium iodide the value, 19- was obtained under varia- 

 tion of the concentration (from 0.029 m to 0.13 m in the aque- 

 ous solution), the volume of electrode solution, and the current 

 density is regarded as a proof of the correctness of the theo- 

 retical treatment. For potassium dichromate, ferric sulpho- 

 cyanate, and ortho-nitro-phenol the migration value of the anion 

 is greater than in aqueous solution. 



1901. B. D. Steele. 



A New Method for the Measurement of Ionic Velocities in Aqueous Solution. 

 Trans. Chem. Soc, 7g, 414. Zeit. f. Elektrochem, 7, 618. 



Apparatus : an H-tube with electrode chambers attached. The 

 H-tube contained the aqueous solution to be investigated ; while 

 the electrode chambers were filled with an " indicator" solution 

 solidified by gelatine. The author measured the ratio between 

 the rates at which the tube's two surfaces of contact approached 

 each other ; the boundaries being detected by the difference in 

 refraction. The indicators employed had one ion in common 

 with the solution to be measured, while the specific velocitv of 

 the other ion was less than that of the ion it followed through 

 the H-tube. Under these conditions the observed rates are 

 proportional to the specific ionic velocities. 



