EXERCISE A-4. TO COMPARE THE SURFACE SOIL 



WITH THE SUBSOIL. 



Equipment: Soil auger or spade; piece of oilcloth 



or heavy paper sixteen inches 

 square. 



Method: With a spade dig a 

 narrow trench a foot deep. Make 

 one side of the trench smooth and 

 note the line at the bottom of plow 

 depth. Examine a handful of soil 

 above and below the line and fill 

 out the following table, comparing 

 the two: 



Fig. 3. — Soil Auger Made 

 by Welding a Three-foot 

 Length of Wrought Iron 

 Gas-pijie onto the Shank 

 of a 1^-inch Wood Au- 

 ger. Additional lengths 

 may be added as desired. 



Observe the line between the 

 surface soil and the subsoil wherever 

 the earth has been cut into, cither 

 l^y a stream or an artificial grade. 

 There is usually a distinct difi'erence 

 in color between the surface soil and 

 the subsoil. 



Discussion: If the soil contained nothing more than 



8 



