36 LABORATORY MANUAL OF AGRICULTURE 



3. Graduated cylinders 100 c.c. 



4. Cheesecloth. 



5. Shears. 



6. Eighteen inches rubber tubing J-inch diameter. 



7. Three soils: sand, loam, and clay. 



Directions. Cut a disk of cheesecloth just large 

 enough to cover the bottom of each tube. Place the 

 cheesecloth in the bottom of each tube. Fill with soil 

 the tubes provided for the purpose within one inch of 

 the overflow pipes. Fill two tubes with sand, two with 

 loam, and two with clay. Place a half-inch layer of gravel 

 on the surface of each to prevent displacement of the 

 soil by running water. Place the tubes in the rack and 

 connect the overflow pipes with short pieces of rubber 

 tubing. 



Fill the supply tank with water and invert it in place 

 over the soil tubes. The supply tank will maintain a water 

 level automatically. 



Note the time at which water was applied. 



Place beakers under each tube to catch the drip water. 

 Note the time at which the water starts to flow from each 

 tube. 



When the flow becomes constant, which will be ten or 

 fifteen minutes after the flow starts, collect the water which 

 percolates through each soil in fifteen minutes. Measure 

 the water carefully and record the amount in the accompany- 

 ing outline form. 



Repeat the process of percolation and measurements twice. 

 Record the amount of water percolating for each fifteen- 

 minute period in the outline form. 



