114 



MEMBRANES (PLASMAHAUT) 



The appended curve (from Loeb) shows the effect of concentration 

 on the attractive force of Na 2 HPO 4 on water. Various concen- 

 trations of this salt from M/8192 to M/8 were put into collodion 

 bags fitted with a manometer. The ordinates are the values for 

 the rise in the level of the solution in the glass tube (after the first 

 twenty minutes) which occurred when the collodion bags filled 

 with different concentrations of disodium phosphate were dipped 



T. 



o 

 I- 



3 

 



I/) 



u. 

 O 



24-O 

 220 

 20O 

 ISO 

 /SO 



120 



too 



BO 



60 



20 



REGION OF PREVAILING ELECTRICAL EFFECT 

 OF ELECTROLYTES 



PREVALENCE OF ATTRACTIVE ACTION OF AN ION '^CREASING 

 UPON THE POSITIVELY CHARGED PARTICLES OF WATER. RULING 



ACTION OF 

 CATION UPON 

 THE POSITIVE- 

 LY CHAR&CD 



PARTICLES 

 OF WATER 



REGION OF PREVAILING GAS 

 PRESSURE. EFFECT OF 



ELECTROLYTES 



<- (TRUE OSMOTIC PRESSURE) 



M M M 

 8IS2 4036 2048 



M M M M M M M 



1024 SIZ 256 128 64- 32 16 

 CONCENTRATIONS 



FIG. 19. 



M 

 8 



M 

 4- 



M 

 2 



IM 



into beakers of distilled water. The abscissae are the logarithms 

 of the concentrations of the phosphate solutions. This curve 

 shows clearly that at a very low concentration of the salt the rate 

 of diffusion of water from pure solvent into the solution through 

 the collodion membrane increases rapidly with increasing con- 

 centration, and that it reaches a maximum at a comparatively 

 low concentration of the salt, viz. : M/128. This increase in rate 

 has been shown to be due to the predominance of the attractive 

 action of the anion upon the positively charged hydrols. With 

 an increase in concentration beyond M/128 the rate of diffusion 



