174 ELECTRIFICATION OF WATER 



face, being cast inside of the same Erlenmeyer flask, and during the 

 experiment the whole area of the flask was submersed in the beaker. 

 The temperature was always 24°C. 



In Fig. 1 the ordinates are the values for the rise in the level of the 

 solution in the glass tube (after the first 20 minutes) which occurred 

 when the collodion flasks filled with different concentrations of cane 

 sugar, grape sugar, or glycerol were dipped into beakers containing 

 distilled water. The abscissas are the logarithms of the concentration 

 of the sugar solution. The reader will notice that for concentrations 

 below m/64 the curves run practically parallel to the base fine while a 

 sharp rise begins at about m/16 or m/8. If the rise is plotted over the 

 concentration (instead of over the logarithms of the concentration) 

 the curve is almost a straight Hne between concentrations of m/32 

 and 1 M (Fig. 2), as was to be expected on the basis of the gas pressure 

 theory. When, however, we make the same experiments with solu- 

 tions of electrolytes, separating them from pure water by collodion 

 membranes, a curious phenomenon is observed, which was partly de- 

 scribed in the first paper; namely, that at a very low concentration 

 of electrolyte the rate of diffusion of water through the collodion mem- 

 brane from pure solvent into the solution increases rapidly with in- 

 creasing concentration and that it reaches a maximum at a compara- 

 tively low concentration^ of the electrolyte. It is easier to follow the 

 facts to be described with the help of the curves given in Fig. 3. 

 The abscissae are the logarithms of the concentration of the solution, 

 while the ordinates give the height to which the hquid in the manom- 

 eter has risen in 20 minutes. The reader will notice that the curves 

 for five sodium salts are given — NaCl, Na2S04, Na2 oxalate, Nas 

 citrate, Na4Fe(CN)6. The solutions must not be acid for this experi- 

 ment, and the hydrogen ion concentration of the solutions of NaCl, 

 Na2S04, and Na2 oxalate was almost that of the point of neutrahty 

 (pH about 6.0, or between 6.0 and 7.0), while the two other solutions 

 were sHghtly alkahne. Beginning with the lower concentrations of 

 the solutions of these salts the curves rise sharply with the increase in 

 concentration, reach a maximum at a concentration of about m/256, 

 and then with a further increase in concentration the curves fall 

 abruptly to reach a minimum, varying for the different salts between 

 m/32 and m/8. After this the curves rise again. 



