188 



KLINOSTAT. 



[CH. VII 



amount of excentric movement of the spindle. If the 

 screw sc is made to project through the disc and press 

 against n, the disc is forced against 7?i and the spindle is 

 secured in an excentric position. 



To get the weight to balance about the spindle the 

 following is the best plan. The screw sc is loosened enough 

 to allow the disc d to be moved by 

 the application of force, but not 

 enough to allow it to slip by the 

 weight of the plant. The plant is 

 allowed to take up its natural posi- 

 tion, which will be with its heavier 

 side downwards: the box is then lifted 

 by a hand placed under it, until the 

 spindle no longer touches the friction 

 wheel, and the boss c (fig. 37) is struck 

 vertically from above with a hammer. 

 The spindle having been thus displaced 

 in the right direction, is replaced on 

 the friction wheel and its state of 

 balance is tested. The hammering must be repeated 

 until, when the spindle is made to rotate, it has no 

 marked tendency to come to rest in one position rather 

 than another. 



The clock can be rotated in the vertical plane by 

 turning on the screw R, and thus the driving gear can be 

 tightened or slackened. When a new loop of silk has to be 

 adjusted on the wheel, or when any operation connected 

 with the experiment has to be performed, the clock should 

 always be stopped by inserting into the balance wheel one 



pL 



FiG. 37. Exp. 217. 

 Copied from the 

 Linnean Society's 

 Journal, 1880. 



