58 Dr. H. J. S. Sand on the Concentration 



notation as above, the flow of copper out o£ the solution at 

 the electrode is 



i g.-equiv. 

 96540 cm. 2 sec' 

 and the flow towards the latter, due to electrolysis 

 ac i g.-equiv. 

 k 96540 cm.- sec* 

 The flow F due to diffusion is therefore 



i / -i ac \ 

 96540 V k)' 



This quantity is variable, increasing continually from its 



original value to the value fx <g ,^ , which it assumes when c 



95540' ac 



has gone down to 0. The quantity — =ra c , which we may 



ic 



call the transport value of the copper in the solution, can,, 



as is known, be determined experimentally for the values of 



concentration and conductivity which exist at the beginning 



of the experiment. For this purpose it is necessary to pass 



an arbitrary quantity of electricity q through the solution,, 



and to determine the decrease in copper in a region bounded 



on the one side by the anode, on the other by solution still 



having the original composition of the liquid (making the 



necessary correction for copper dissolved from the anode). 



This decrease is equal to — ttt^tt; g.-equiv., and has been 

 ^ k 96540 fc ^ 



determined by Schrader* in the case of certain mixtures — 



the same mixtures which have been employed for this present 



work. If the value of this decrease in grammes be a, and 



the quantity of silver deposited in a silver voltameter by the 



current employed be /3, both of these values having been 



given by Schrader, then 



and 



ac 



9 _ 



a. q 







K 



96540 



' 31-59' 96540 ~ 



107-66' 



1 — 



ac 



K 



107-66 31-59 









> • 



(12) 



107-66 



the numbers 31-59 and 107*66 being the equivalent weights 

 of copper and silver respectively. 



* Ztschft.f. Elektrochemie, iii. p. 502. 



