[lynde-dupréj 



ON OSMOSIS IN SOILS 



107 



To test the validity of this theory I made experiments* with the 

 apparatus ilhistrated in Fig. 2 



The semi-permeable membrane was a layer of heavy clay subsoil 

 held in the tube by one thickness each of cotton cloth and of wire gauze. 



The solutions used were at 10 per cent, sugar solution and a 10 per 

 cent, potassium sulphate solution. 



The rate at which the distilled water moved up through the subsoil 

 and into the solution was measured by the movement of the liquid 

 column in the horizontal tube B. 



The results obtained from these experiments show: — 



(1) that this clay subsoil acts as a semi-permeable membrane; 



Bf 



-k^l- 



'-«-- 





ïç^ ixx^ ^^lu 



^ 



Tube B 



Rubber s top'r 

 ^Tube A 



Cloy subsoil sol) 



- — Dist wafer 



lay subsoil 

 -Cotton cloth 



Figure 3. Modification of Pfeffer's experiment. The semi-permeable membranes 



are 6, 4 and 2 grams of clay subsoil respectively. The solution is that formed 



by boiling clay subsoil in distilled water. 



(2) that water moves through the clay subsoil towards a solution; 



(3) that the rate at which the water moves increases with the 

 temperature. 



In 1912 we carried on a series of experiments j with the following 

 objects in view: — 



*C. J. Lynde. Osmosis in Soils. Soils act as Semi-Permeable Membranes. 

 Journal of Physical Chemistry, Vol. 16, No. 9, December, p. 750 (1912), and Pro- 

 ceedings of the American Society of Agronomy, Vol. 4, 1912. 



tC. J. Lynde and F. W. Bates. "Osmosis in Soils." Journal of Physical 

 Chemistry, Vol. 16, No. 9, December, p. 766 (1912), and Proceedings of the American 

 Society of Agronomy, Vol. 4, p. 108, 1912. 



