ON THE WALK OF QUADRUPEDS. 17 



The manner in which the step of Quadrupeds is performed, explained. 



The oblong figure of a horse, which may be considered as resting 

 upon its legs as upon pillars fixed upon the ground in A B C D, forms 

 a four-sided rectangle ; the line drawn perpendicular from the centre 

 of gravity of the horse would fall upon E near the centre of the 

 rectangle, and thus the posture of the animal would be most secure. 

 Afterwards the step is made by the foot behind, as the left, C, which, 

 by pressing the firm ground with a strong effort backwards, the centre 

 of gravity is moved forward from E to G, and this being performed 

 quickly, the foot-B is raised and moved forwards to H, which motion 

 can be made with greater effect, because the centre of gravity falls at 

 first within the triangle A B D ; next, it falls within the four-sided 

 figure (trapezium) A B F D, — that is, it is supported upon three or four 

 columns. The next three feet, A D F, remain firm, and include the 

 centre of gravity G; the left foot B, being moved forward to H, and 

 by this impulse the centre of gravity is tranferred to I — that is, to the 

 centre of the four-sided figure (rhombus) A H F D ; the steps of the 

 two left feet being concluded, the motion of the right hind foot D 

 begins, and afterwards that of the fore foot A. The step of quadrupeds 

 is always performed in the order just explained. 



Although attentive observation may be sufficient to prove these 

 facts, yet it is the duty of the philosopher to enquire into the advan- 

 tages and necessity of such a process. It is an invariable law of 

 Nature, while she avoids, as much as possible, the disadvantages and 



vol. i — no. r. c 



