1905-6.] Electrolysis through Precipitation Films. 463 
the soaking-out process with the other solutions, and that this in 
some way hinders the transference of other ions across the film. 
8. Chemically equivalent solutions of ammonium chloride and 
of ammonium bromide, if not too concentrated, have the same 
specific conductivity, but they are affected to different extents by 
a film of aluminium hydroxide. The experiment just discussed 
showed that this small difference was distinctly recognisable by 
means of a chromic hydroxide film prepared from sulphate 
solutions. 
Chemically equivalent solutions of a d - tartrate and of the 
corresponding racemate have also the same specific conductivity, 
but they also might be affected by the film to different extents. 
If this were so, the obvious explanation would be that in the 
racemate solution some of the c?-ions and £-ions were associated 
to form racemate ions. 
As the result of the experiment with sodium ammonium 
e£-tartrate and sodium ammonium racemate was that the conductivity 
of the two solutions was diminuted to exactly the same degree, the 
conclusion seems warranted that in the solution of the racemate 
there could be no considerable concentration of racemate ions. It 
might be reasonably expected, however, that d-ions and Hons would 
be differently affected by a film consisting of an optically active 
substance. Experiments are now in progress in this direction, and if 
a suitable optically active film can be obtained, it should be possible, 
by electrolysis in the case of electrolytes, or by diffusion in the 
case of electrolytes and non-electrolytes, to effect the resolution 
of racemic compounds or mixtures into their optically active 
components. 
{Issued separately , January 4, 1907.) 
