54 THE PHYSICAL PROPERTIES OF SOILS 



NINTH EXERCISE 



THE LATERAL MOVEMENT OF CAP- 

 ILLARY MOISTURE 



The forces which produce capillary movement of 

 moisture in soils in the field may act in direct opposi- 

 tion to, or at any angle with the force of gravity. 

 During periods of drought, growing plants may be 

 supplied with water by a vertical movement from the 

 moist sub-soil or by a lateral movement from the ad- 

 jacent surface soil. 



Prepare the two brass cylinders used in the Fifth 

 Exercise, Part 11. , by filling one with loam or silt and 

 the other with clay. Make the soils up to 15 

 or 20 per cent of moisture and pack the cylinders level 

 full by means of a wooden rammer. Cap the lower 

 end, and tie a piece of moist cheese-cloth over the top 

 of each cylinder and place them in a horizontal posi- 

 tion. Weigh at the beginning of the experiment and 

 at twenty-four hour intervals for one week. 



At the end of the period take samples through the 

 side tubes and determine the per cent of moisture in 

 each. 



Discuss the results with respect to the total loss of 

 moisture and to its distribution, at the close of the 

 experiment. 



References : 



Bureau of Soils, Bulletin No. 10. 

 Bureau of Soils, Bulletin No. 38. 



