TBJS WOBK OF ROOTS 



93 



in the figure. Let the flaps made by cutting remain in 

 place. Fix round, flat corks in the cut places, and 

 bend the flaps so as to support the corks as firmly 

 as possible. For the 

 axle use a knitting 

 needle, impaling two 

 rubber stoppers 

 upon it, one on each 

 side of the zinc disk, 

 to hold the latter in 

 place. They should 

 press firmly against 

 the disk, to insure 

 its turning with the 

 axle. The two up- 

 right wooden sup- 

 ports fastened to a 

 block of wood are 

 pierced by holes just large enough to admit the small 

 glass tubes in which the axle rests. Each of these is 

 closed at the end, to keep the axle from slipping toa 

 far. "We place the apparatus in a sink, and attach a 

 rubber tube to a faucet. At the end of this tube is a 

 piece of glass tubing drawn to a point. The manner 

 in which this is supported is shown in the figure. It 

 should be wedged firmly in place by wooden wedges, 

 and be so directed that the stream will strike the 

 wheel just at its rim. The stream must be powerful 



7G. Water-wheei for the purpose of malting 

 germinating seeds revolve rapidly. 



