N EG ATI VE OSMOSIS 



141 



attractive action of the ion with the opposite charge. The 

 appended curve (Fig 34, from Loeb) shows the effect of concentra- 

 tion on the attractive force of Na2HP04 on water. Various 

 concentrations 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 



2'^o 



2ZO 



200 

 ^ /so 



H 



s: /60 



Z /^O 



z 







1- 



D 



_l 

 



in 



O 



> 



UJ 



/20 



/OO 



ao 



60 



^o 



20 



REGION OF PREVAILING ELECTRICAL EFFECT 

 OF ELECTROLYTES 



PREVALENCE OF ATTRACTIVE ACTION OF /^NION ''iS'^,^'?5'^''i 

 UPON THE POSITIVELY CHARGED PARTICLES OF WATER, F^tVALLNCE 



CF REPELUNa 

 ACTION OF 

 CATION UPON 

 THE POSITIVE- 

 -LY CHARGED 



PAR.TICLE5 

 OF WATER 



R.ECION Cr PR.EVAILINO1 &AS 

 PRESSURE, EFFECT OF 



ELECTROLYTES 

 (true 05KOTIC PRE55URE) 



IM 



Fig. 34. 



dipped 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 

 concentration, 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 ])e due to the predominance of the attractive 

 action of the anion upon the positively charged hydrols. With 

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



