MOVEMENT 45 



the strip of paper will have progressed a very short dis- 

 tance, 0*1 millimetre for instance. It will have com- 

 pletely passed through the rollers at the end of a run of 

 30 kilometres. The needle, which writes on the paper, 

 is made of brass, and the paper itself is coated with a 

 layer of white zinc, and called "papier couche" in the 



Fig. 32. — The instrument is seen obliquely from behind. The dial of the clock is 

 visible. The strip of paper is in position between the rollers, and the needle is in 

 the act of tracing. The teeth of the comb have already imprinted hourly sub- 

 divisions on the paper. At B the end of the shaft acts by means of a clapper on 

 a ratchet-wheel, which iu its turn controls the movement of the rollers by means 

 of aa endless screw. 



trade. On this latter the brass leaves a very fine and 

 clearly defined track. It never wears out like a pencil, 

 neither does it require ink like a pen. To obtain a 

 curve of the movement, the needle must have imparted 

 to it a uniform motion by means of clockwork, and it 

 5 



