AGRICULTURE. 



(/) Firmly tie over the bottom of each tube a square 

 of cheese-cloth. (Fig. 16.) 



(c) Weigh each tube separately, and then record :he 

 weights. 



(d) Fill the tubes three-fourths full of dried sand, clay, 

 humus, and loam respectively. 



(e) Carefully weigh each tube with its contents, and 

 record the. weights. 



(/) Now fill each tube with water which has been 

 leached from stable compost, taking care to record the 

 exact time when the water first comes in contact with the 

 soil. 



(g) Support or suspend these tubes in an upright po- 

 sition (Fig. 1 6), and allow the water from each tube 

 to drip into a separate vessel. Observe and record the 

 time required for the water to begin to drip from each 

 tube. Keep 

 each tube filled 

 with the leach- 

 ed water until 

 the soil is satur- 

 ated. Through 

 which tube did 

 the water pass 

 most rapidly.? / 

 This passage of 

 water down- 

 ward through . 

 the soil is call- >\ J 

 ed percola- 

 tion. 



(//) Compare the color and the odor of the water per- 

 colated. Through which of these soils will soluble 

 plant-food most readily leach ? Which soil will absorb 

 the most plant-food from the water which percolates 

 through it ? 



CTH,\\ 



t APPARATUS FOR EXPERIMENT 5. 



