210 THE ROYAL SOCIETY OF CANADA 



lil)eiated by the reaction. Mr. Welsh's experiments shewed, however, 

 that in point of fact iodine and not ferric salt is reduced. This result 

 has an important bearing on the theory of electrolytic reduction of 

 ferric salts; it led to the experiments of Burt-Gerrans described below. 

 (Winter, 1909-1910). 



No. 8. 2\ li. Rosebriujh and W. Lash Miller: — Mathematical 

 theory of the changes of concentration at the electrode brought about by 

 diffusion and by chemical reaction. Owing to the chemical changes 

 which accompany electrolysis, the composition of the electrolyte at 

 the electrodes is different from that in the body of the solution. Dif- 

 fusion currents are consequently set up which tend to remove these 

 differences; and if convection be avoided, the concentration of any 

 constituent at any point in the solution will depend only on the initial 

 composition of the solution, and on the amounts which have been 

 carried to or from the electrodes by diffusion and by electrolytic 

 migration. 



In the simpler cases, at all events, these changes of concentration 

 are susceptible of mathematical treatment; Weber and Sand have 

 considered the case of electrolysis with constant currents, and War- 

 burg has deduced an equation for the stationary state on electrolysis 

 with a sinusoidal current through a diffusion layer of ''infinite" length. 

 The present paper deals with the whole problem in a systematic 

 manner, and includes the discussion of electrolysis with intermittent, 

 successive, and sinusoidal currents, without restrictions as to the dura- 

 tion of the electrolysis or the length of the column of liquid through 

 which the diffusion takes place. The increasing application of the oscillo- 

 graph to the study of instantaneous conditions at the electrode, led 

 us to pay particular attention to the changes which take place within 

 the first fraction of a second after throwing on the current, while 

 Richards' work on electrolysis with alternating currents, followed by 

 the interesting experiments of LeBlanc and of Reichenstein with 

 copper electrodes in cyanide solutions, induced us to include the case 

 of non-instantaneous chemical reactions between the primar}- pro- 

 ducts of electrolysis and the other constituents of the solution. Ex- 

 perimental methods are suggested by which, in suitable cases, the 

 velocity constants of such reactions might be determined. {Jour. 

 Phys. Chem. 14, pp. 81G-884, 1910). 



No. 9. W. H. Eastlake: — Distribution of acetic and succinic 

 acids between water and solutions containing two organic liquids. — 

 Measurements of the distriljution of any analytically determinable 

 substance between two immiscible solvents furnish a means of de- 

 termining the effect of concentration on the chemical potential of 

 the given substance in one of the solutions if it is known for the other. 



