382 TRAXS. ST. LOUIS ACAD. SCIENCE. 



I also examined the velocity of ditlusion of the zinc vitriol so- 

 lutions into gelatin. Similar results to those of B v. Tietzen- 

 Hennig were obtained. However, I have for the present post- 

 poned drawing any conclusions from them. We have here a far 

 more complicated phenomenon than would appear on first sight. 

 For not alone does the zinc vitriol diffuse into the water contained 

 in the gelatin, but also water^from the zinc vitriol solution. How 

 complicated this phenomenon is will appear from the fact that, 

 if a concentrated zinc vitriol solution is allowed to diffuse into a 

 concentrated gelatin, crystals of zinc vitriol separate out in the 

 upper parts of the gelatin. Before, therefore, we can compare 

 experiments on diffusion with those on electric conductivity nu- 

 merically, it is necessary to follow these phenomena more close- 

 ly, and with this I am engaged at present. 



