UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 835 
Contribution from the Bureau of Public Roads 
THOMAS H. MACDONALD, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
August 6, 1920 
CAPILLARY MOVEMENT OF 
SOIL MOISTURE 
By 
WALTER W. McLAUGHLIN, Senior Irrigation Engineer 
CONTENTS 
Page 
Object . 2 
Plan of Experiments 2 
Rate and Extent of Movement of Soil 
Moisture by Capillarity 13 
Effect of Gravity on the Movement of 
Soil Moisture by Capillarity .... 39 
Evaluation of Empirical Curves . . . . 47 
Page 
Open Versus Covered Flumes .... 54 
Effect of Temperature on Soil-Moisture 
Conditions ...56 
The Capillary Siphon 58 
Capillary Movement of Moisture From a 
Wet to a Dry Soil 63 
References . 69 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
- . 1920 
