THE WORK OF ROOTS 



97 



ing- wax. Let the earth be reasonably moist when the 

 seeds (well soaked) are placed in it, but do not water 

 it further except by pouring water into the flower-pot, 

 from which it will diffuse through the soil. After a few 

 days examine the roots, to see what direction they 

 have taken. What is the greatest distance from the 

 flower-pot at which the direction of growth of the roots 

 is affected! By using a shallow box (about one and 

 one -half inches deep), with a glass bottom, and plac- 

 ing the earth directly on the glass, we can watch the 

 growth of the roots without disturbing them; but, 

 since the glass affords no drainage, very little water 

 may be used, else the soil will become so saturated 

 with moisture as to spoil 

 the experiment. The re- 

 sult will depend partly 

 on the amount of water 

 present and partly on 

 whether the roots are 

 growing in sand, clay or 

 sawdust. 



What direction should 

 the side roots take to 

 explore the soil most 

 effectively for moisture? In a box with a sloping 

 glass side (see Fig. 80), filled with moist soil, 

 place several seeds with caulicles (about an inch 

 long) pointing straight downwards. Mark on the 



. Apparatus for observing the behavior 

 of roots as they encounter obstacles. 



