MODES OF PROGRESSION USED BY MAN. 133 



same time the notion of the duration of each pressure, that of 

 the foot to which this pressure belongs, and also the length of 

 time during which the body is suspended. This notation of 

 rhythms is constructed in a very simple manner from the 

 tracings furnished by the apparatus. 



FIG. 34. 



Let us return (fig. 34) to the curve which corresponds witli 

 the act of running in man. Below this figure let us draw 

 two horizontal Hues 1 and 2 ; these will form the staff on 

 which will be written this simple music, consisting only of 

 two notes, which we shall call right foot, left foot. From the 

 commencement of the ascending part of one step-curve be- 

 longing to the right foot, let us let fall upon the staff a per- 

 pendicular (a) ; this line will determine the commencement of 

 the pressure of the right foot. A perpendicular (') let full 

 from the end of the curve will determine where the pressure 

 of this foot ends. Between these two points, let us trace a 

 broad white line ; it will expi-ess, by its length, the duration, 

 of the pressure of the right foot. 



A similar construction made on the step-curve (No. 1) will 

 give the notation of the pressure of the left foot. The nota- 

 tions of the left foot have been shaded with oblique lines to 

 avoid all confusion. 



Between the pressure of the two feet there is found to "be silence 

 in the rhythm ; that is to say, the expression of that instant 

 of the course when the body is suspended above the ground. 



