482 ELECTRICAL CHARGES AND ANOMALOUS OSMOSIS 



pH 4.7) from water of pH 4.7, the Ce(N03)3 solution assumes a posi- 

 tive charge as is shown in Table VII. If now the Ce causes the liquid 

 cylinders inside the pores to be charged negatively an electrical 

 transport of water into the solution must occur commencing at a low 

 concentration of the salt and in the way characteristic for the elec- 

 trical transport curves in Figs. 1 and 3. The curve for Na4Fe(CN)6 

 in Fig. 5 suggests that Na4Fe(CN)6 causes solid isoelectric gelatin to 

 assume a negative charge. The question is, whether this happens 

 only in the case of trivalent (and probably tetravalent) cations and 

 tetravalent anions. It is obvious that all the transport curves for 

 salts with divalent cations, Mg, Ca, and Ba, in Figs. 4 and 5, commence 

 to rise at a slightly lower concentration than the transport curves for 

 the salts with monovalent cation, KCl, NaCl, and LiCl. It might be 

 argued that the salts with bivalent cation transfer also a positive 

 charge to isoelectric gelatin at a concentration above m/8 and that the 

 same is true for the salts with monovalent cations, the difference 

 being that the concentration of the salt required for this effect is very 

 high for salts with monovalent cation, slightly lower for salts with 

 bivalent cation, and very low for salts with trivalent cation. 



On the other hand it should be pointed out that the transport curve 

 for cane-sugar rises even more rapidly than that for CaCl2 so that there 

 is in reality no need to assume that the CaCl2 charges solid isoelec- 

 tric gelatin positively. The difference between the transport curves 

 for NaCl and CaCl2 in Fig. 4 is no greater than the difference between 

 the transport curves for cane-sugar and grape sugar. As far as the 

 experiments on anomalous osmosis are concerned, there is no reason 

 to assume that the salts with divalent cations or monovalent cations 

 transfer a positive charge to the isoelectric gelatin or to gelatin of any 

 pH or that the bivalent anions transfer a negative charge, though it 

 is not absolutely disproved that this may not happen at high concen- 

 trations of the salts. 



It was thus far left undecided whether the positive electrification 

 of isoelectric gelatin by Ce(N03)3 in Fig. 4 was due to a change of the 

 pH so that the gelatin was no longer isoelectric or to the formation of a 

 salt between isoelectric gelatin and Ce(N03)3 dissociating into a 

 positively charged complex gelatin- Ce ion and negatively charged 

 NO3 ions. To settle this question experiments were made with 



