WHAT PLANTS NEED 7 



in water. The cup is placed in a small pan of water. 

 On top of the seeds we place a cup in which is a piece 

 of wood. On top of this we place a three-cornered 

 file or piece of iron for the iron bar to rest on. The iron 

 bar is held at one end by the eyebolt a. At the other 

 end we hang iron weights (hitching blocks or flatirons). 

 A ruler is placed upright at / and a mark made where 

 the iron bar crosses it. (In the figure a part of the 

 outer cup is cut away to show the seeds.) 



FIG. 4. A way to test the swelling force of seeds. 



As soon as the seeds begin to swell and the bar rises 

 above the mark, put on more weights until it stops 

 rising. 



Before removing the weights tie a piece of wire or 

 rope to the bar at the point b and see if by raising it 

 you can lift as much weight as the seeds did. Perhaps 

 if you fasten the wire to a stick which three or four 

 persons can take hold of at once, you may be able all 



