MANUAL OF GENEEAL AGEICULTUEE. 11 



divided air-dry sand, sandy loam, loam and clay. Do not 

 separate the coarse and fine particles. Compact the soil 

 by letting the tubes drop onto a book, taking care to 

 let the tubes drop the same number of times and the same 

 distance. Support the tubes so that the ends dip about 

 one inch in water in the bottom of a pan. Observe the 

 height to which the water has risen at the end of 1 hr., 

 2 hr., 4 Mr., 6 hr., at the next meeting of the class, and 

 at each meeting thereafter for two weeks or more. Keep 

 a paper by each tube showing 1, the height of the mois- 

 ture, 2, time and day of each reading. Record results 

 in tabular form in your note-book. 



Questions: 1. Which tube shows the most rapid 

 rise ? 2. At the end of an hour, which shows the greatest 

 rise? 3. At the end of a week? 4. What effect does 

 size of particles have on rapidity of movement ? 



6. EFFECT OF DRAINAGE ON SOIL TEMPERATURE. 



Materials : Five-gallon oil can with one side removed, 

 wooden box approximately the same dimensions. 



Fill each with the same kind of soil and apply the 

 same amount of water until drainage begins in the box. 

 There will be no drainage from the can. If necessary, 

 loosen a board in the bottom of the box. Let the two 

 stand out of doors until the following day. Begin as early 

 in the morning as possible and take the temperatures 

 hourly at depths of 1 and 3 inches until 5 P.M. Record 

 results on a piece of paper left by the vessels. 



Let some pupil who lives near wet land record the 

 temperatures of this land together with the temperature 

 of adjacent dry land at convenient intervals some Satur- 

 day. Compare his temperatures with those of the experi- 

 ment. Tabulate the results. Give explanations for dif- 

 ferences in temperatures. 



Question: If drainage effects the temperature, how 

 may it affect a crop? 



