128 IHE ROYAL SOCIETY OF CANADA 



work of Dixon and Joly* and that of Askenasy, it is possible that water 

 can be raised by soils to heights greater than 10 meters, or 34 feet, by 

 surface tension and tensile stress. 



Osmosis. — In recent work carried out in this laboratory it has 

 been shown if 



(1) that one clay subsoil, at least, acts as a semipermeable mem- 

 brane; 



(2) that its efficiency as a semi-permeable membrane increases 

 with its depth; 



(3) that water moves through this subsoil towards a soil solution. 

 In more recent work, the results of which have just been sent to 



the press, it has been shown that the finer the grains of soil in a soil 

 constituent the greater is the eflBciency of the soil constituent as a 

 semi-permeable membrane. 



If under field conditions subsoils act as semi-permeable membranes 

 and if the concentration of the soil solutions in the upper layers of soil 

 is greater than that of the soil solutions in the lower layers of soil, it is 

 possible that soils may raise water to heights greater than 10 meters by 

 osmotic pressure. 



Summary 



Part I. — The new method of measuring the capillary lift of soils 

 has enabled us to measure a capillary lift approximately three times 

 as great as the maximum lift measured by the old method. The ^ime 

 required for the experiment was 20 hours instead of 18 months. 



The advantages of this method are: — 



(1) the moisture moves through a wet soil; 



(2) the moisture passes through a very short column of the wet 

 soil and thus friction is reduced to a minimum; 



(3) the time required to make an experiment is reduced from 

 months to hours; 



(4) the final measurement is a fairly accurate measure of the 

 capillary lift of the soil. 



Part IL 



(1) The finer the grains of a soil constituent the greater is 

 the capillary lift of the constituent. 



*Proc. Roy. Soc, Vol. LVII, No. 340 (1894), also Annals of Bot., Vol. VIII ; 

 Phil. Trans., Vol. 186, 1895 (B). 



tC. J. Lynde and F. W. Bates. "0.smo.sis in Soils." Journal of Physical 

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

 of Agronomy, Vol. 4, p. lOS, 1912. 



