Solutions of Saponin, Peptone, and Albumin. 



Table III. 

 Solutions of Albumin. 



571 



Age of 

 Surface 

 (days). 



1 

 2 



3 



4 



5 



(i 



7 



8 



9 



10 



11 



12 



13 



14 



15 



20, 



25, 



30, 



Molecular Thickness of Surface Layer. 

 Concentration : 1 part in 



133-7 



280 



2-3 



5-6 



5-6 



t> 



7 



6 



8 



6 



6 



6 



6 



6 



6 



6 





6 





6 





6 



"e 





6 





1300 



3-4 



4 



4-5 



1808 



4 

 5 

 6 

 6 



7 

 7 



8-9 



10 

 12 



10,750 



4-5 

 5-6 



7 

 7-8 

 8-9 

 10 

 10 



15-16 



16 

 17 



22 



282,800 



9-10 



10 



10 



10 

 10-11 



12 



11 



12 



Conclusions regarding the nature of the process 

 of Surface Separation. 



The process of surface separation plays an important part 

 in many physical, chemical, and physiological phenomena, 

 and a more thorough knowledge of its nature is therefore 

 very desirable. All the solids whose solutions exhibit this 

 effect possess the property of lowering the surface tension of 

 water. The concentration in ihe surface-layers of a solution 

 of a substance possessing this property must be greater than 

 that in the body of the solution, since this surface concen- 

 tration tends to lower the potential energy of the system. 

 There will be a contrary tendency towards equalization of 

 the concentration owing to the osmotic pressure gradient in 

 the neighbourhood of the surface, so that equilibrium will 

 finally be established. 



Hence, the most obvious explanation of the phenomenon 

 of surface separation is that it is an extreme case of surface 

 concentration. It is possible that if increase of concentration 

 has a large effect on the surface tension, and only a small 

 effect on the osmotic pressure, equilibrium is not attained 



