MEASUREMENTS 



277 



Suppose, for example, it is desired to measure the tractive 



effort in the transport of a load 

 P. The hook C would be attached 

 to the load, and a pull exerted 

 on the ring until movement begins. 

 The value marked would be that 

 of the tractive effort (fig. 165). 



206. Regnier's Dynamometer. 



This was constructed to Buffoon's 

 requirements. It consists of two 

 steel springs, A and B, united at 

 their extremities by iron stirrups, 

 Fic - 166 C and D. In the middle of B 



Regnier's dynamometer. is a small p i ece o f metal w hich 



can move the jointed lever lorn, by means of the crank b. 

 The arm m of the lever guides the pointer I over a graduated 

 scale supported by the spring A. The graduations serve a double 

 purpose, one corresponding to the efforts of traction as when C 

 is fixed and a pull exerted 

 on D (renal force) and the 

 the other to efforts of pres- 

 sure as when pressure is 

 exerted on B (see 89 and 

 fig. 166). 



207. There a re a consider- 

 able number of dynamo- 

 meters, but it is impossible 

 and unnecessary to describe 

 them all. Various models 

 are used in clinics, such as 

 that of Bloch, the stheno- 

 meter^ 1 ) In this case the 

 deformations of an elliptical 

 spring are transmitted by 

 a pinion carrying pointers. 

 The graduation is double 

 for traction and pressure 

 (fig. 167). 



208. Dynamometric Re- 

 gisters or Dynamographs. 



To observe the variations 



of force, Morin constructed 



to Poncelet's instructions, Fi &- 167 - Bloch's Sthenometer. 



a dynamometric register, the moveable end of the spring 



carrying a tracing point, which moves over the paper in pro- 



(*) Bloch (Comptes Rendus Biol. 1895). 



