ANALYSIS OF WALKING. 73 



which, according to the received definition, consists 

 in that mode of locomotion in which the body 

 never quits the ground. In running and leaping, 

 on the contrary, we shall see the body is entirely 

 raised above the ground, and remains suspended 

 during a certain time. In walking, the weight of 

 the body passes alternately from one leg to another, 

 and as each of these limbs places itself in turn 

 before the other, the body is thus continually 

 carried forward. 



" This action appears very simple at first sight, 

 but its complexity is soon observed when we seek 

 to ascertain what are the movements which occur 

 in producing this motion." 



This shows us that we may define walking as a 

 succession of paces. " A pace is the series of move- 

 ments executed between two similar positions of 

 the same foot." Now, a series of movements implies 

 something tolerably simple. Marey tells us, then, 

 that walking is a succession of paces, that a pace 

 is a series of movements. It remains, then, for us 

 to inquire what properties may be presented by a 

 series of movements. 



Walking may be described in various ways. As 

 proposed already, it may be described as a series of 

 movements of the parts (limbs) which produce the 

 locomotion; as a series of muscular contractions 

 moving the limbs ; or, did we possess sufficient 

 knowledge, we might describe a pace in walking by 

 stating what nerve -centres are in action coinci- 

 dently, and what is the order of their successions. 



M. Marey has in part described locomotion by 



