GROWTH. 09 



is tied to the tip of a shoot of a Coleus, Tomato, or Potato, or 

 leaf of a Narcissus grown in a pot. The plant is set directly 

 under the pulley and the string is passed over the pulley, and 

 attached to this end is a weight G of one gram or more to keep the 

 threat taut. As the plant grows in length it allows the weight 

 G to descend, turning the pulley as it does so. The pointer is at- 

 tached directly to the pulley, and as the elongation takes place it 



FIG. 64. 



Lever auxanometer. (After Oels.) Z, lever ; g, balance-weight on lever ; 

 G, counterpoise to keep the string taut ; /, string. 



passes downward along the scale. Since the length of the pointer 

 from the center of the pulley is 16 cm. and the radius of the pulley 

 is 2 cm., the amount of growth is magnified 8 times. The apparatus 

 is set up with the pointer at zero on the upper end of the scale. 

 Observations of its position should be made at least three times 

 daily. A growth extension of i to 5 cm. daily may be expected 

 under favorable circumstances. 



