MOTION. 473 
path described by the centre 
of gravity in the time ¢, and the 
distance of the centre from the 
earth at the end of that time. 
The time occupied in running 
between the raising of the leg 
from the ground and the setting 
it down again is equal to the 
duration of the step, together 
with the portion of time during 
which the body swings in the 
air; or, it is the time in which 
¢ (fig. 262) advances from c, to 
¢;, being the time between the 
raising of the left leg and the 
setting it down again, but this 
time is divided into two por- 
tions, namely, that whilst c 
CTI 
ay 
oe 
. Figures designed by Weber, to illustrate the laws of running. 
moves from c, to c,, and that whilst it moves From these principles it is obvious that no 
from c, to c,; the latter portion is the duration man in the act of running could possibly be in 
of the step; the former the time in which the ; 
body swings freely in the air. Fig. 266. 
Fig. 265. na 
ie 
Preparing to run, and running, from designs by Flarman. In fig. 265 ¢ d falls behind the advanced foot, so 
‘that the posterior leq be ws only a small portion of the weight of the body, but is in a position to push the centre 
of gravity forwards before quitting the ground. Y 
