THE WORK OF ROOTS 



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this question. The essential parts are an ordinary 

 clock and a small tub (of wood or, better, of wood 

 fiber) , with two holes to admit a stiff wire or knitting- 

 needle. The wire should be bent at one end and 

 wired to the minute-hand of the clock. In order to 

 prevent the minute-hand from slipping, it may be 

 necessary to fasten it to its axle with a little solder or 



75. Arrangement for causing germinating seeds to revolve slowly. 



sealing-wax. Short bits of glass tubing are inserted 

 in the holes in the tub, to act as bearings. The ger- 

 minating seeds are to be pinned to corks impaled on 

 the wire; the roots should point in various differ- 

 ent directions; pour sufficient water into the tub so 

 that the seeds dip in it each time they revolve ; cover 

 the tub with a piece of glass, place over this a piece 

 of cardboard or cloth to exclude light, and set the 



