14 



THE FOOD OF PLANTS 



CHAP. 



The Pood is left in the Plant when the 

 Water evaporates 



We now understand that any food the plant 

 obtains from the soil must first be dissolved in the 

 water, and that it can then pass up into the plant. 

 We also have learnt that the water evaporates from 

 the surface of the leaves. Let us see what will 



become of the sub- 

 stances dissolved in the 

 water when this hap- 

 pens. 



Experiment 11 



To find this out, 

 pour the water con- 

 taining the salt, the 

 sugar, and the sul- 

 phate of copper into 

 three porcelain eva- 

 porating basins, and 

 place the basins over 

 a lamp. The water 

 will soon boil away, leaving the salt, sugar, and 

 sulphate of copper behind in the porcelain dishes. 



We may see from this experiment that substances 

 dissolved in the water that is always passing into 

 the roots will remain behind when the water evapo- 

 rates from the leaves. 



FIG. 



