CONDUCTIVITY OF COLLOIDAL MIXTURES 



309 



where the salt ions penetrate and the effect is to hinder the 

 further entrance of both anions and cations. 



In figure 2 the cyhnder was inmiersed first in NaCl and after 

 ten minutes CaCL was substituted. The second part of the 

 curv^e shows no effect of the Na ions which are abeady present, 



Fig. 4. 



and there is no indication that the ions of the second salt are in 

 any way prevented from entering by the ions of the first salt. 



Figure 3 shows with the colloidal mixture the more rapid 

 penetration of the NaCl ions. Fenn^ comes to a similar con- 

 clusion but attempts no explanation. 



' Fenn, W. O. Similarity in the Behaviour of Protoplasm and Gelatine. Proc. 

 Natl. Acad. Sci. 2:539. 1916. 



