OSMOSIS. 



The following instances are taken from Pfeffer : l 

 Copper Ferrocyanide Membrane. 



267 



Parchment Paper Membrane. 



CONCENTRATION. 



1 "5 per cent, calcium chloride 



2 ,, gum-arabic 



1*5 ,, calcium chloride + 2 

 per cent, gum-arabic 



RISE OF FLUID IN MEASURING TUBE 

 IN MM. PER HOUR. 



Experiment I. 



1-2 

 1T4 



Experiment II. 



10-3 



1-3 



11-3 



Temperature in both experiments, 17*4 C. 



In cases, however, where the two constituents of the solution have 

 a common ion, each salt diminishes the dissociation of the other, so that 

 the pressure of the mixture is less than the sum of the pressures of the 

 two components. 2 



Thus for a double salt 



1 Pfeffer, loc. cit., p. 68. 



2 From Adie, Journ. Ohem. Soc., London. 1891, vol. lix. p. 344. 



