FACTORS AFFECTING THE GERMINATION OF SEEDS 155 



4. One hundred and twenty kernels of corn of uniform 

 size and known to be of strong vitality. 



5. Balances weighing to one half gram. 



6. Graduated cylinder, 100 c.c. 



Directions. Number the washpans from one to six. 

 Put into the first three pans equal amounts by weight of air- 

 dry sand and into the last three equal amounts by weight 

 of air-dry clay. The pans should be about two thirds 

 full. 



Add water slowly by measure to one pan containing sand 

 until the soil, when thoroughly mixed, appears to contain the 

 proper moisture content for the best growth of seeds. Add 

 the same quantity of water to the second and third pan, 

 mixing it well with the soil. 



In the same way determine the proper amount of water 

 to add to the clay soil for the best growth of plants. Make 

 up all three pans containing clay to the same moisture 

 content. 



Smooth the surface of the soil in all the pans and plant 

 twenty kernels of corn in each pan. Plant the kernels at 

 a depth of one inch. 



Treat the pans as follows : 



1. Sand. No treatment. Set in a warm place to ger- 

 minate. 



2. Sand. Thoroughly saturate with water. Set in a 

 warm place to germinate. 



3. Sand. No treatment. Place where the temperature 

 is cool, but not cold enough to freeze. 



4. Clay. No treatment. Set in a warm place to ger- 

 minate. 



