70 



Elementary Plant Physiology. 



brane. Observe the consequences, and note behavior of 



column of mercury for a day or two. 



64. Lifting power of a transpiring branch — Fit 



a rubber or cork 

 stopper to the top 

 of a burette, or 

 graduated tube. 

 Secure a woody 

 branch of any con- 

 venient species with 

 active leaves. If 

 possible, cut the 

 branch from the 

 plant by bending 

 under water the 

 portion to be 

 severed, then using a 

 sharp knife. If this 

 is impracticable, cut 

 the branch much 

 too long, and bring 

 it into the labora- 

 tory, and cut to 

 proper length, as 

 shown in Fig. 50. 

 Make a hole in the 

 stopper to admit the , 

 branch. Seal the 

 fitting externally 

 with gelatine which 

 has soaked in water 

 for an hour or two. 



_, „ . . Invert the prepara- 



Fig. 45.— Preparation to demonstrate lifting power of . ^ 



a leafy branch. After Detmcr. tion, and fill the 



