THE AIR IN THE SOIL 



27 



EXERCISE 11 



Object. — To determine the influence of compacting the 

 soil upon the amount of air space in it. 



Procedure. — Follow the instructions given in Exer- 

 cise 10, only before adding the water thoroughly pack the 



Fig. 8. — Measuring the water before adding it to the soil. 



soils in the cans with a short piece of broomstick or the 

 head of a small mallet. 



Conclusion. — Compare the amount of air space in the 

 soil before packing, as determined in Exercise 10, with 

 that after packing, as found in this exercise. In dry 

 farming regions, where the soil is liable to be too loose and 

 hght, would it be advisable to roll or pack it? 



