50 LABORATORY MANUAL OF AGRICULTURE 



the paraffin is still soft, plug up the hole in the bottom of 

 the pot. 



Place an inch of gravel in the bottom of the second pot 

 to insure good drainage and see that the hole in the bottom 

 of the pot remains open. 



Fill both pots to within one inch of the top with loam 

 soil. 



Add water slowly by means of the graduated measure to 

 the soil in the paraffined pot until it has absorbed all that it 

 will. This will require twenty or thirty minutes. Record 

 the amount of water added. Add the same amount of water 

 to the unparaffined pot, allowing any water that will to 

 escape at the bottom of the pot through the drain. Place 

 the two pots in the window of the laboratory where they will 

 receive sunlight. 



Let the pots stand two days. At the end of two days 

 plant three grains of corn in each pot at a depth of two 

 inches. 



Place a thermometer in each pot with the bulb two inches 

 below the surface soil and record the temperature of the soil 

 at the tune the corn was planted. Take the temperature 

 every two days for thirty days. Record data in the accom- 

 panying outline form. 



Add enough water every three days to the pot with good 

 drainage to keep the corn growing well. Add the same 

 amount of water to the poorly drained paraffined pot. 



Measure the height of growth of plants when temperature 

 of the soil is taken. 



At the end of thirty days remove the plants from both 

 pots and examine the root growth. 



