22 



FARM MACHINERY 



Another method is to rotate the reel by clock-work. 

 Then distances along the paper are proportional to time. 



FIG. 12 GIDDINGS RECORDING DYNAMOMETER, WHICH HAS THE REEL 

 DRIVEN BY CLOCK-WORK 



If the velocity be uniform, the distances are approxi- 

 mately proportional to the distance passed over as be- 



