764 Rural School Leaflet. 



Drain off the water and suspended soil in it into another jar leaving 

 sand and gravel in the bottom of the first jar. Let the contents of the 

 second jar settle for five minutes, and drain as in the first instance, 

 into the third jar. In the second jar is left silt. 



Let the contents of the third jar settle for two or three days, 

 then drain off the water. You have left clay. 



Compare the sand, silt, and clay as to origin, color, size of particles, 

 and stickiness. Do you find any more humus in one sample than in 

 another? 



Rubbing the soil between your fingers will help you to compare the 

 size of the particles. Bring out the idea that the particles of sand are 

 not only large but also angular; that the particles of humus may be the 

 finest, and give a velvety sensation when rubbed between the fingers. 

 Place some humus soil on a hot stove and notice how it burns. The 

 sand and clay will not burn. The clay particles are fine. This gives the 

 soft, oily feeling when rubbed between the fingers. The particles which 

 are between the clay and sand in size are called silt and also have a 

 soft feeling. 



Squeeze some of each of the soils in your hand, then notice which 

 falls apart when you open your hand. The soil which remains in a 

 compact mass when you open your hand is the most sticky. Separate 

 the soil into very sticky (clay) ; slightly sticky (silt) , and not sticky at 

 all (sand). 



Which soil ought not to be worked while it is wet? Why? With 

 which soil would it not make any difference ? 



Name the material in our soils coarser than sand. 



Bring out the idea that sand can be detected by its large 

 particles, clay by its stickiness, and humus by the fact that it will 

 burn. 



Subject matter. Our farm soils are composed of stones, gravel, sand, 

 silt, clay, and humus. All the particles above i — -2 5" (i mm.) in diameter, 

 are considered either stones or gravel ; while sand includes all the particles 

 between i — 25" to i — 500" (i mm. to .05 mm.) in diameter, ranging 

 from coarse sand to very fine sand. Silt includes all particles between 

 I — 500" and I — 5000" (.05 mm. to .005 mm.) in size. Clay includes all 

 particles between i — 5000" to 000. (.005 mm. to .0000 mm.) in diameter. 

 These fine measurements of the sand and clay have been computed by 

 the use of a microscope, and are standard. Humus varies from visible 

 fragments of woody tissue and pieces of twigs to a black powdery material. 



The different proportions of these ingredients give us our various farm 

 soils. If sand predominates, we have a sandy soil; if clay, a clay 



