CLASSIFICATION AND PROPERTIES OF SOILS. 55 



less open or more finely pulverized soil act as 

 the fine tubes in conveying moisture. 



EXPERIMENT 7. (a) Take four glass tubes one-half 

 inch or more in diameter and four feet in length * 

 (Fig. 18). Over the bottom of each of these tubes firmly 

 tie a square of cheese-cloth. 



(^) Thoroughly pulverize the dried clay and loam. 

 Firmly and evenly fill each tube with the sand, clay, loam, 

 and humus respectively. Stand them in a pan of water 

 with a layer of gravel in the bottom, and record the 

 time of so doing. Keep the pan well filled with water. 



(<r) At intervals from one to three hours during the 

 first day or two note the height of the water in each 

 tube. After the second day, once a day will be often 

 enough to make observations. 



(dj Continue the observations and records until the 

 water no longer rises in any tube. 



(<?) In which tube did the water rise most rapidly? 

 In which to the greatest height? This power of drawing 

 water upward through the soil is called capillarity. 



EXERCISE 2. From the data obtained in performing 

 these experiments, write up the physical properties of each 

 of these four kinds of soil. Your description of each 

 soil should cover the following points: Color, weight of 

 a cubic foot, light or heavy to work, power to absorb 

 heat, power to retain heat, power of holding soil particles 

 together, porosity, power to absorb and retain water, 

 capillarity, and any remarks. 



[References after Chapter III.] 



* Straight lamp-chimneys may be substituted for the long glass 

 tubing. It is more economical, and will give satisfactory results, 



