104 



ELECTRIFICATION OF WATER AND OSMOTIC PRESSURE 



cases of dynamical equilibrium between two processes which occur 

 simultaneously in opposite directions; e.g., chemical equilibrium be- 

 tween reversible reactions. 



Procter'2 and his collaborators have developed a theory of swelling 

 of colloids based on the assumption that swelling is a purely osmotic 

 phenomenon. On the basis of this theory we may consider the 



300 

 280 



260 

 240 

 220 



60 



40 



20 



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 



Time in hours 



Fig. 6. Curves of osmotic pressure of 1 per cent solutions of gelatin phosphate, 

 gelatin chloride (nitrate), gelatin citrate (tartrate), and gelatin sulfate (pH = 3.5). 

 Pressure in mm. of column of gelatin solution. 



surface and all the other solid parts of a block of gelatin to act as 

 membranes permeable for water and crystalloids but not for gelatin. 

 The osmotic conditions inside a solid block of gelatin which is 



13 Procter, H. R., and Wilson, J. A., /. Chem. Soc, 1916, cix, 307. Procter, 

 H. R., and Burton, D., /. Soc. Chem. Ind., 1916, xxxv, 404. 



