SOIL AND SOIL PREPARATION 



39 



is equal to twice the volume of each, the soil contains no air. 

 If less, the difference indicates the amount of air in the soil. 

 Suggestion. Compare loose soils with compact soils. 

 Which contain most air? Compare plowed soil with un- 

 plowed soil. Result? 



27. CHARACTER OF SOILS 

 Object. To show what kinds of soil best retain water. 



Apparatus. A frame with lamp chimneys arranged as in 

 Figure 11. Each lamp chimney is closed with a perforated rubber 



C D 



FIG. 11. 



stopper and has a short piece of glass tubing to carry off the water, 

 which drains into beakers. 



Method. Place various soils in the chimneys. 



A, 100 grams of gravel. 



B, 100 grams of sand. 



C, 100 grams of roadside soil. 



D, 100 grams of rich garden soil. 



E, 100 grams of leaf mold from forest. 



F, 100 grams of dry leaves pulverized. 



In 



