A UNIT IN AGRICULTURE 15 



Ex. 38. Effects of Air Upon Seed Germination in Soil. 



Into each of two fruit jars containing rich sandy loam, put a few 

 seeds of wheat, corn and beans. Moisten the soil in both jars, screw 

 the top on one tight, being sure to keep the rubber band in place. 

 Leave the other open. Set both in a warm lighted place and note re- 

 sults at the end qf one week, two weeks, three weeks. What does this 

 experiment teach? 



Ex. 39. Relation of Light to Growth. 



Prepare two fruit jars as in Exercise 38. Put one jar in a closet 

 or dark basement to exclude the light, and note results. Substitute 

 for the fruit jars and seeds flower pots containing growing plants. 

 Are. plants attracted by the light? Plan an experiment to prove. Why 

 do trees grow taller when planted near together than when planted 

 far- apart ? 



Ex. 40. Relation of Temperature to Growth. 



Note. The work will vary with the facilities for maintaining 

 fixed temperatures. Try to germinate seeds and grow plants at dif- 

 ferent temperatures. Work out fairly accurate answers to such ques- 

 tions as the following : What is the lowest temperature at which corn 

 will germinate ? At what temperature does it germinate most quick- 

 ly? etc. 



Ex. 41. Preparation and Properties of Oxygen.* 



Ex. 42. Preparation and Properties of Hydrogen.* 



Ex. 43. Preparation and Properties of Nitrogen.* 



Ex. 44. Preparation and Properties of CO*.* 



Ex. 45. Plant Food. 



* To be performed by teacher before the class. Pupils should observe close- 

 ly and record in full. 



