THE PHYSICAL PKOPE&TIES OF SOILS 



63 



vinced farmers that this is not so, and numerous scientific 

 experiments have shown that,when compared with artificial 

 manures, farmyard manure shows to best advantage in 

 dry seasons, i.e., under conditions least favourable to its 





JP IG> Q. Apparatus showing the Height to which Water 

 will rise in Tubes of different Calibre. 



action. There is little room for doubt that the water 

 retained by the humus of the soil is largely beneficial to 

 plants. 



Capillarity. It has been shown that if the quantity of 

 water in the soil exceeds a certain amount, the force of 

 gravity overcomes that of surface tension and the excess 

 is drawn downwards. If the soil contains less than that 



