SOIL MOISTURE AND PREPARATION OF SOIL. 61 



osmosis. Thus the soil water not only dissolves 

 the plant-food, but through capillary action and 

 osmosis actually carries this food to the plant. 



EXPERIMENT 9. (a) Take any single-stemmed grow- 

 ing plant, place the roots in 

 a wide-mouthed bottle half 

 full of water. 



() Make the bottle air-tight 

 (to avoid the evaporation of 

 the water) by splitting a cork 

 into halves, hollowing out the 

 center, and fitting them about 

 the stem of the plant ; now 

 fill any crevice about the 

 stem, or in the top of the cork, 

 with melted paraffin.* Invert 

 the bottle to see if any watei 

 escapes ; if so, the cork is not 

 fitted air-tight, and melted 

 paraffin must be applied 

 where it leaks. 



(^) When the bottle is air- 

 tight weigh it, and record 

 date and weight. The follow- 

 ing day place it where the 

 plant will be exposed to direct 

 sunlight, and weigh every day 

 or two for two or three weeks. 

 How much water has the plant 

 used ? Of what use to the 

 plant was the water? 



Hellriegel, through his experiments, found 



IQ. APPARATUS FOR 

 EXPERIMENT 9. 



* Paraffin melts at a low temperature, and will not injure the 

 plant if carefully applied, 



