HUMAN MOVEMENTS 



131 



point of the curve. It was important from one point 

 of view to know the number of steps taken. For this 

 purpose we placed in the centre of the track a bell 

 which rang at regular intervals, and with which the 

 performer kept time. The intervals could be regulated 

 by means of a pendulum, the length of which could 

 be varied at pleasure. It was situated inside the 

 laboratory, and could control the rate of ringing for 

 anything between 40 and 120 strokes a minute. The 

 number of steps per minute being thus known, one 

 could substitute in the odographic tracing the total 

 number of steps taken for the time occupied, and by 



1 2 3 b 5 

 Fig. 89. — Chart of the fixed odograph to show paces of different velocity. 



dividing the distance traversed by that number, we 

 could arrive at the average length of stride. 



It was from such data that Fig. 90 was constructed. 

 This diagram showed that the length of stride increased 

 as the step was quickened, that is to say, when the 

 rate was between 40 and 75 per minute. This was just 

 as the brothers Weber had showed ; but when the 

 rate was quickened beyond that point, the length of 

 stride decreased, and finally at 85 steps per minute 

 and onwards the total rate of progression began to 

 diminish. That is to say, the shortening of the 

 step became so pronounced that in spite of the increase 

 in frequency, the total distance traversed in a given 



