86 LABORATORY EXERCISES 



EXERCISE 82 

 KINDS OF SOIL 



Apparatus and Materials. Drinking glasses or bottles, teaspoon, 

 gravel, sand, clay, and black loam. 



a. Get samples of 4 kinds of soil : gravel, sand, clay, and loam. 

 Get as dark a loam as possible. 



Crush each sample of soil with your hands, and rub it between 

 the tips of your fingers. Which is made up of the largest 

 particles? Which of the smallest? 



6. Wet a teaspoonful of each kind of soil; then work it be- 

 tween the fingers. Which soil sticks together best? Which 

 crumbles most easily? 



c. Put a heaping teaspoonful of the gravel into a drinking 

 glass half-full of water. Stir the water thoroughly, let it settle 

 one minute, then pour off the liquid into another dish. To the 

 gravel that remains in the glass add as much water as you 

 poured off, and stir the water again. Let the liquid settle 

 for one minute; then pour off the water. Write down your 

 results. 



d. Treat each of the other kinds of soil with water, as you did 

 the gravel, and record all the results. 



Does much or little material settle out from the water 

 that is poured off? Which soil settles least in the minute 

 given it? Which most? Describe the materials left after 

 the second stirring with water. 



EXERCISE 83 

 SOIL TESTS 



Apparatus and Materials. Black loam, white sand, filter paper, 

 funnel, porcelain or "tin" evaporating dish, burner, beaker or flask, 

 test tube, dilute hydrochloric acid, 2 saucers, thermometer. 



