296 



THE HUMAN MOTOR 



222. Ergographic Apparatus. These are undoubtedly the most 

 useful because they are the most practical and correct. The 

 classic ergograph is that of Mosso, (*) an Italian physiologist, who 

 gave it his name. It comprises two parts : 



Fie. 206 1 207 



The point O is fixed ; when stationary the 

 spring balance shows the value of P which 

 will overcome the effort of friction (/> ; in 

 action it will indicate P <, from which <f> 

 can be deduced. The work done per 

 revolution will be : 



1 . Fixed Portion .In Mosso 's model assume that the registration 

 of the flexor muscles of a finger is to be taken ; the hand is laid, 

 palm upwards, on a cushion, A (fig. 208), whilst the index and ring 

 fingers are introduced into the rigid tubes G and N ; the back of 

 the forearm resting on B. Next a bracelet, CD, is tightened 

 round the wrist, and sometimes a second in the middle of the 

 forearm. The whole hand and forearm are therefore sufficiently 

 fixed, while the middle finger remains free. 



Fie 90S 



Fixed portion of Mosso's ergograph. 



2. The Inscribing Slide. The moving portion is a slide travelling 

 on two bars, N,N', and carrying a pen, PQ. To the base of the 

 slide is attached, on one side, the cord S, which is connected to 

 the middle finger, and on the other side a cord T, passing through 

 the axis of a screw C and over a pulley V, to sustain a weight 

 P. The screw C regulates the initial position of the slide so that, 

 when stationary, the finger does not undergo traction (fig. 209). 



(!) Angelo Mosso (Arch. Ital. Biol. vol. xiii. p. 123, 1890. La Fatigue, 

 French translation, 1894). 



