78 



SOILS AND PLANT LIFE 



hole through this cork, through which a glass tube is thrust 

 so that the lower end reaches into the sirup in the carrot 

 while the other end extends into the air. Set the carrot 



upright in a glass of 

 water, taking care, 

 however, that the 

 upper end of it is 

 not covered with 

 water. Record each 

 day how far the sirup 

 has risen in the tube. 

 Small rubber tubing 

 may be used to con- 

 nect the glass tube 

 to another one when 

 the sirup has reached 

 the top. 



C n cl u s ion . — 

 When two liquids are 

 separated b}' a plant 

 or animal membrane, 

 they tend to mix 

 through it, this phe- 

 nomenon being loiown 

 as osmose. The 

 denser liquid, which 

 in this case is the 

 sugar sirup in the 

 carrot, draws the less 

 dense, or the water 

 outside, much more 

 rapidly than the water draws the sirup. This is known as 

 the law of osmose. Since the dense substance trades 

 only a little of itself for a great deal of the thinner sub- 



FiG. 25. — A root taking water and forc- 

 ing it upward through the glass tube. 



