HUMAN LOCOMOTION. 



55 



by the effect of their flexion ; and this takes place at the very moment 

 when the body was at its greatest elevation. 



Galloping, a gait that children in their amusements sometimes 

 adopt, gives the tracings shown in Fig. 8. The tracings produced by 

 leaping are shown in Fig. 9. 



Fig. 8. Man galloping with the Right Foot first. Step-curves and reactions. There is an 

 encroachment of one curve over the other, and then a suspension of the body. The curve 0, 

 which corresponds with the reactions, shows the effect of the two successive impulses exerted 

 on the body by the feet. 



Among the characters belonging to the various modes of progres- 

 sion, the rhythm of the impact of the feet is one of the most striking. 

 The strokes of the feet upon the ground give rise to sounds the order 

 of whose succession is sufficient for a person, with an ear accustomed 

 to them, to recognize the kind of pace which produces them. In order 

 to give the figure of each of these rhythms, Prof. Marey employs the 

 musical notation, modified so as to furnish at the same time the notion 

 of the duration of each pressure, that of the foot to which this pressure 



Fig. 9. Leap on Two Feet at once (D and G). The line B, the curve of reactions, shows that 

 the maximum of elevations corresponds with the middle of the pressure of the feet. 



belongs, and also the length of time during which the body is sus- 

 pended. This notation of rhythms is constructed in a very simple 

 manner from the tracings furnished by the apparatus. Fig. 10 repre- 

 sents the curve which corresponds with the act of running in man. 

 Below this figure let us draw two horizontal lines, 1 and 2 ; these will 

 form the staff on which will be written this simple music, consisting 

 only of two notes, which M. Marey calls right-foot and left-foot. From 



