THE GRAPHIC METHOD 83 



drums. Each drum is provided with an adjusting 

 screw, by means of which the drum may be inclined until 

 the strip of paper is stretched uniformly throughout its 

 height. This adjustment should preferably be made 

 upon the sliding drum. When the adjustment is 

 complete, the abscissae drawn by a writing lever in 

 successive revolutions will exactly coincide. The 

 clockwork drum does not slide along the bench. 

 Both drums may readily be removed from their 

 hearings. 



Beneath the clockwork drum is a circular plate of 

 the exact size of that of the medium spring kymo- 

 graph. This plate rests on two feet and in fact 

 supports the anterior end of the steel bench. The 

 clockwork drum is driven by a kymograph in which 

 the vertical steel drum-rod and sleeve are replaced by 

 a short rod the top of which is flush with the upper 

 plate of the kymograph. The feet of this kymo- 

 graph are hollowed to lit three rounded pins. When 

 the kymograph is set upon these pins, it is at once 

 "centred" and all side motion is prevented. A 

 coupling sleeve is now let down from the shaft of the 

 clockwork drum until two projections on the under 

 surface of the coupler engage with corresponding 

 slots in the kymograph rod. The clockwork operates 

 like that of the medium-spring kymograph, having 

 ten changes of speed. The speeds are, however, 

 faster as a stronger spring is used, the maximum 

 being about seven centimetres per second. 



To smoke the paper, the coupler is raised, the 



