CHILDREN'S GARDENS 153 



then make whatever changes are necessary in the grade 

 of their garden, to either carry the water off better, or 

 to stop it from running off so fast, whichever is de- 

 sired, or perhaps, put in drains to relieve wet spots. 



While the vegetables are growing, they use a great 

 deal of water, which they take in through their roots, 

 and which they pass out through their leaves. The 

 children need not take this for granted, but can prove 

 it in the following ways. Let them pick leaves from 

 a plant, like the lettuce or the beet, and grind them 

 up between their hands, and squeeze out a quantity 

 of water. That the water is constantly passing up 

 through the plant, can be shown by noticing that the 

 leaves on the growing plants are stiff and stand up- 

 right, and if a plant is pulled out of the ground and 

 laid in the hot sun, it soon wilts. This shows that 

 the water is constantly leaving the plant. Pulling it 

 out of the ground has cut off its supply of water. 

 Many plants will revive and the leaves straighten up 

 again, if placed in water, so the plant can take up 

 some more. To show that the plant is constantly 

 passing water out of the leaves, put a glass vessel 

 over the top of the plant, and also pull some fresh 

 leaves and put them under an inverted glass vessel, 

 so that any moisture that comes from the leaves will 

 not escape. These experiments are best performed in 

 the sunlight. The moisture that comes out of the 

 leaves will be collected on the inside of the glass. 



The plants make a great deal of heat in themselves. 

 This can be shown by picking half a dozen plants, 



