98 EXPERIMENTAL PLANT PHYSIOLOGY 



work meclianism. An apparatus of this kind is called 

 a Klinostat. 



To make a simple Klinostat. — A cheap clock can 

 easily be converted into a klinostat. 



The minute-hand must be removed, as it is not re- 

 quired, and will be found to be in the way if it is not 

 cut off. A thin rod, about four inches long, is then 

 attached to the axis of the hour-hand so that it pro- 

 jects horizontally from the axis. 



As the hour-hand revolves the attached horizontal 

 rod must necessarily revolve with it, and to this rod 

 can be attached the seedling that is to be experimented 

 with. 



Experiment 62 



Aim. — To find out whether the downward growth of 

 the root is caused by the attraction of gravity. 



Method. — A pad of damp moss is wrapped round the 

 end of the klinostat rod and kept in position by a 

 rubber band. Care must be taken that the moss is 



Fig. 49 



made secure, otherwise it will slip and not revolve with 

 the revolution of the rod. 



Some germinating peas are fastened to the pad by 

 means of pins. 



The clock is wound up and set under a bell-jar. 



Observations. — The root does not grow downwards, 

 but continues to grow in whatever direction it was 

 placed on the damp pad. 



