LEAVES 157 



do they differ in appearance? Give the probable reason. 

 Do you find any moisture in the glass which was dry at the 

 start? 



Suggestion. Place a spray of hydrangea in a bottle of 

 water. Set it in one scale pan and balance it. What 

 happens after an hour or two? Why? How do you ac- 

 count for it? 



Repeat the experiment, using a potted plant in a scale pan, 

 having first sealed the pot with paraffin paper. Then 

 counterpoise it. 



Procure three test tubes or slender bottles of the same 

 size and shape. Fill them three fourths full of water and 

 mark the level with a thread or rubber band. Label the 

 tubes a, 6, and c. Now select from the same plant or from 

 plants of the same kind two branches of equal size and bear- 

 ing the same number of leaves. 



Place them in two of the tubes thus : 



(a) Tube open, containing nothing but water. 



(&) Tube open, but containing a branch from which the 

 leaves have been removed. 



(c) Tube open, containing the other branch bearing all 

 its leaves. 



After six hours note the level of the water in each tube. 

 Which tube loses most water? How do you account for 

 the difference? 



138. LEAVES 



Object. To find out the relative amount of mineral 

 matter in leaves. 



Apparatus. Young leaves from new shoots and old leaves 

 fallen from the same tree, evaporating dishes, and Bunsen burner. 



