AUTOMATIC RECORD OF GROWTH 



II 



wire which sucks in a rod of soft iron attached to the plate- 

 carrier. The force required for bringing about the oscillatory 

 movement thus acts directly, without any intervention of 

 the eccentric. 



The amplitude of oscillation of the plate is about 3 mm. 

 It is important that the vertical recording plate should be 



Fig. 3. Complete apparatus. 



p, plant ; s, s', micrometer screws for raising or lowering the 

 plant ; c, clockwork for periodic oscillation of plate ; 

 w, rotating wheel. 



so adjusted that its distance from the tip of the writer will 

 remain the same during the excursion of the index, as well 

 as during the lateral displacement of the plate moved by 

 the clockwork. Failure to secure this makes the dot-marks 

 unequally distinct ; in the worst cases some of the dots 



