THE CII.VXGE IN FORM 363 



developed sufficed to raise the load. Kepeat this 

 with other loads. Join the dots. The resulting 

 line is a curve showing the absolute force of the 

 muscle at successive intervals from the beginning 

 to the end of the phase of rising energy. 



Eecord with this same muscle an isometric 

 contraction (page 350). With the aid of the 

 graduation scale of the isometric spring ascer- 

 tain the maximum tension developed in the 

 isometric contraction. Compare this result with 

 that secured in the experiment just concluded 

 on the time relations of developing energy. 



ELASTICITY AND EXTENSIBILITY 



Elasticity and Extensibility of a Metal Spring. 

 Clamp the ergograph (Fig. 61) to the table in 

 such a way that the writing point of the ergo- 

 graph spring shall rest against a smoked drum. 

 Attach a scale-pan to the spring near the free 

 end. Turn the drum once round by hand, thus 

 describing an abscissa on the smoked paper. 

 With the forceps place 2 ten-gram weights very 

 carefully on the scale-pan. 



The spring extends. Turn the drum 2 mm. 

 and add another 20 grams to the scale-pan. 



A further extension of the spring will be 

 recorded. 



