42 



THE VEGETATIVE EUNCTIONS OF PLANTS 



by a very simple experiment. A small leafy branch of 

 any plant (a branch of some evergreen is excellent to 



Fig. 33. — Experiment to illustrate the so-called "lifting power" of 

 transpiration, d, dish of mercury; mt, surface of mercury column that 

 has risen in the glass tube, gt; rt, rubber tube; br. branch of a pine tree, 

 whose leaves are transpiring. 



use) is inserted in the end of a piece of glass tubing about 

 3 feet long. The joint between the glass and the branch 



