CLASSIFICATION AND PROPERTIES OF SOILS 51 



Let the temperature curve of the loam be indicated by 

 an unbroken line , that of sand by a broken line 



, and that of clay by a dotted line , and that 



of humus by a line and then a dot 



Compare. Give a reason for the differences in tem- 

 perature between these soils. 



(e) On the next bright day again saturate one box of 

 each of these soils, and place the dry and wet soils in 

 the bright sunlight. At noon record the temperature of 

 each, and remove all to the shade indoors. 



(f) Note the temperature at 2 P.M. and 4 P.M. Which 

 soil, dry, retains the greatest amount of heat ? Which 

 soil, wet, retains the greatest amount of heat? 



(g) What conclusion of practical value do you draw 

 from your results? Could you improve the condition of 

 any or all of these soils with regard to the absorption 

 and retention of heat? How? 



PART 3. (#) Thoroughly moisten these soils and try 

 to mold a handful of each kind (sand, clay, loam, humus) 

 into some desired form. 



(<) Which soil has the greatest power of holding its 

 particles together ? Which the least ? Which soil' 

 will be most liable to puddle ? Which most apt tc 

 bake ? 



(f) Mix each of these soils with one-fifth its bulk of 

 lime, and repeat (a). 



(d] Mix each with one-third sand, and repeat (a}. 



(e) Mix each with one-third humus, and repeat (0). 

 Of course, one could not apply sand, lime, or humus 



in quite such large proportions in the open field, but it 

 could be done for house plants, and in smaller propor- 

 tions in gardens and fields. Which of these soils would 

 be improved for working by (<r)? (d)l (e)J 



EXPERIMENT 5. (a) Procure three pieces of tubing of 

 equal lengths and diameters from two to two and one- 

 half feet long, and one-half inch or more in diameter. 



