ii FOOD OBTAINED BY THE PLANT FROM SOIL 15 



Now if we suppose the soil to contain food for 

 the plant, which food is soluble in water, we can 

 understand how the plant may be fed by this 

 means. 



The roots are always sucking up water, 

 which passes through the plant and evapo- 

 rates from the leaves, and this continuous 

 stream of water leaves behind the food it 

 brings with it, so that the plant is continu- 

 ally being supplied with fresh food. 



The Soil is found to be partly Soluble in 

 Water 



Let us now examine the soil itself to see if any 

 part of it is soluble in water or no. 



Experiment 12 



In order to find out what part of the soil is 

 soluble in water, take a little garden mould and 

 shake it up for some time with distilled water, and 

 let it settle. The clear water contains the part of 

 the soil which is soluble dissolved in it, and the rest 

 has settled down. 



Pour off the clear water into a small evaporat- 

 ing basin and place the basin over a spirit-lamp. 

 The water will soon boil away, leaving a powder 

 in the bottom of the dish. This powder is the 



