EFFECT OF FATIGUE 



129 



intensity 3. This is the intensity which is always used 

 unless the contrary be stated. In order to exhibit the effect 

 of fatigue, the second record is taken after a period of rest 

 of only 15 minutes. The upper record (vibration-frequency 

 100) gives the normal value of L to be "ii second ; the 

 lower record shows that the latent period has been prolonged 

 to *i6 second on account of fatigue (fig. 78). 



The experiment was repeated with a different specimen 

 and with a vibrating recorder giving 50 vibrations per 

 second. The record (fig. 79) shows again that the latent 

 period is prolonged under fatigue, from the normal - i second 

 to -14 second. The effect of fatigue is independently 

 seen in the record, in the relative sluggishness of the respon- 

 sive movement. The slope in the response of the fresh 

 specimen is almost vertical, with successive dots very widely 

 spaced. In the response of the fatigued specimen a great 

 contrast is observed in both these respects. 



I give below a tabular statement showing results of 

 different experiments on the effect of fatigue : — 



Table II. — Effect of Fatigue on the Latent Period. 



