CONSTRUCTION AND USE OF THE DYNAMOMETER. 



123 



Fig. 97. 



Dynamometer, or Force-measurer. 



spring balance, with one hook attached to the plow 

 and the other to the whipple-tree. The amount of 

 force required to draw the plow is accurately meas- 

 ured on the scale by the index or pointer, a. 



Sometimes the motion of this index is multiphed,or 

 made greater and more easily seen, by means of a cog- 

 wheel and rack-work ; but this renders the instrument, 

 at the same time, more complex. 



Another form of this instrument is shown in Fi^. 98, 



Ellipt 



where the ends of the oval spring, Q, Q,, are attached 

 to the plow and draught. The harder the force exert- 

 ed by the team, the closer together will the sides of 

 this spring be brought, causing the rod, E, to press 

 against the index or pointer, and showing the precise 

 degree of force on the circular scale. 



