HOW WATER MOVES THROUGH THE PLANT. 55 



Material For root pressure : One or more potted plants like a begonia, 



garden balsam, etc. A long glass tube about the same diameter as that of 

 the plant stem ; some rubber tubing to connect the glass with the stem, and 

 to connect sections of tubing if necessary. 



For transpiration : Some succulent leaves and leafy shoots, like gera- 

 nium, coleus, balsam, etc. Some small glass bell jars. A potted coleus 

 plant (or balsam), some sheet rubber to cover the pot and earth closely, and 

 a bell jar to cover the plant. 



