8 MANUAL OF GENERAL AGEICULTUEE. 



soil, collecting the soil in a pail until you have about a 

 quart. If there is no marked line between soil and sub- 

 soil, sample to a depth of one foot. 



Without filling up the hole go to at least one other 

 part of the field and in a similar manner obtain another 

 sample, place in the pail with the first sample and mix 

 thoroughly. Save about a quart as a sample of the field, 

 and keep air-tight to prevent loss by evaporation. 



Continue digging to the depth of about one foot be- 

 low the surface soil and collect a sample of subsoil by 

 shaving thin slices as before and placing in the pail. Fill 

 up the hole. Return to the original hole and obtain a 

 sample of subsoil, mix the two subsoils and keep air-tight 

 as was done with the surface soil. 



3. MICROSCOPICAL EXAMINATION OF SOIL 

 PARTICLES. 



Materials : Compound microscope, sand, loam or silt, 

 clay soil, or clay. 



Place a few grains of sand on a glass slide and ex- 

 amine with low power of a microscope. 



Make drawings of several of the particles and de- 

 scribe them with reference to color; shape (angular, 

 rounded, or irregular) ; simple or compound (joined to- 

 gether) coarse, medium or fine. 



Mix loam or silt with a little water and examine a 

 drop, using medium power. Draw and describe as above. 



Mix clay soil with water and examine a drop of the 

 slightly muddy water using the high power. Notice that 

 the soil particles are really minute rocks and humus. 

 Find dark particles of humus. Find flocculated particles 

 of clay, i.e. a number of particles united to form a com- 

 pound particle. Draw and describe. Keeping a clay soil 

 in good condition is largely a matter of keeping the par- 

 ticles thus flocculated or united into small crumbs. 



