CAPILLARY MOVEMENT OE SOIL MOISTURE. 5 



the auxiliary experiments, various types of soil were packed in layers 

 or one end of a column or box contained soil of one type and the 

 other end soil of a different type. 



METHOD AND EQUIPMENT. 



A confined soil column was used and the method differed from that 

 usually employed by other investigators only in the size and arrange- 

 ment of soil columns. The columns used in these experiments are 100 

 square inches in cross-sectional area and much larger than the col- 

 umns usually employed. A feature made important in the present 

 work is the use of inclined columns. 



One side and the bottom of each flume were made of wood with 

 metal lining and the other side was of plate glass. In the discussion 

 of the experiments the term " flume " will be used to designate the 

 soil column and its container. 



Uniform soil was packed into the flumes and wicks extended 

 from within the water in the tanks up into the flumes. After the 

 soil had been placed in the flumes the tanks were filled up to the 

 initial level and this level rather constantly maintained throughout 

 the experiment. 



At 9 a. m. of each day and frequently at other hours the outward 

 extent of the soil wetted by capillary moisture was measured, and the 

 water in the tanks was brought up to the initial elevation with 

 measured quantities of water added directly to the tanks. Soil sam- 

 ples were taken at various points in the wet soil area, at such inter- 

 vals of time as deemed advisable and always at the end of an ex- 

 periment. All the flumes or columns were protected by canvas from 

 the direct rays of the sun and from the rain. 



MEASURING THE ADVANCE OF THE CAPILLARY MOISTURE. 



The outward extent of the wetted soil area, indicating the extent 

 of the moisture movement at any time, is plainly visible through the 

 glass side of the flume. The wetted soil is of a darker color and 

 the line of demarcation is very distinct. The position of this line as 

 seen through the glass side was traced upon the glass. The position 

 of these markings with reference to the surface of the water in the 

 tank is determined by five direct measurements made in the way and 

 to the points as follows : 



Five lines are drawn along the glass side of the flume parallel to 

 the longitudinal axis of the flume. The first line is at the top of 

 the glass; the second line is 2^ inches lower; the third is 5 inches 

 from the top and at the middle of the glass side; the fourth is 7| 

 inches from the top, while the fifth is at the bottom of the flume 

 and 10 inches from the top line. The intersections of the marks on 



