8 



What 18 the soil made of? 



Summary. The experiments made so far have 

 taught us these facts: — 



1. Soil contains water, grit or sand, silt, clay, a part 

 that burns away, and some white chalky specks. 



2. The top layer of soil to a depth of about eight 

 inches is different from the soil lying below, which is 



Surface soil Subsoil 



b Btands for the part that burns away 



Fig. 3. 



Columns showing what 100 parts of dried 



soil and subsoil were made of 



called the subsoil. It is less sticky, easier to dig, and 

 darker in colour. It contains more of the material that 

 burns away, but less clay than the subsoil. 



3. When soil is dried it is not sticky but hard or 

 crumbly ; as soon as it is moistened it changes back to 

 what it was before. But when soil is burnt it com- 

 pletely alters and can no longer be changed back again. 



