HINTS ON HORSEMANSHIP. 19 



feet off the ground, and clasps the chair with his legs, 

 by the muscular exertion of his lower limbs he can jump 

 the chair along. The muscular force is there employed on 

 the foreign fulcrum, the ground, through the medium of 

 the legs of the chair. His muscular action strikes the chair 

 downward and backward ; and if the chair be on ice, it will 

 recede, so would also the feet of a horse in attempting to 

 strike forward. If the chair be on soft ground, it will sink ; so 

 would also a horse, in proportion to the force of the muscular 

 stroke. But if the resistance of the ground be complete, the 

 re-action, which is precisely equal, and in opposite directions 

 to the action, will throw the body of the man upward and for- 

 ward : and by clasping with his legs he will draw the chair 

 also with him. But he can only accomplish in this way a very 

 little distance, with a very great exertion. 



If the jockey made this muscular exertion every time his 

 horse struck with his hind feet, his strength would be era- 

 ployed on the foreign fulcrum, the ground, through the 



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