34 



THE PHYSICAL PROPERTIES OF SOILS 



admit the water. Use a siphon flask to keep the water 

 at a constant level. 



Note the time required for the water to reach the 

 bottom in each ; and the rate of percolation per hour 

 under a given head of water, kept constant by means 

 of the siphon flask. 



SPRING-BOARD COMPACTOR 



Repeat the above, using the. following soils and mix- 

 tures : 



Percolator No. i — Loam or silt. 



Percolator No. 2 — Mixture, one part loam 



one part organic matter. 

 Percolator No. 3 — Clay. 

 Percolator No. 4 — Mixture, one part clay, 



one part sand. 



Tabulate the results and calculate the rate of perco- 

 lation in surface inches per hour. Discuss the effect 

 of texture and the presence of organic matter upon the 

 rate of percolation. 



