THE LENGTH OF THE STIRRUP 23 



is, how to prepare ourselves to meet this anticipated 

 force. 



It is of supreme importance, and must be 

 thoroughly grasped before any further advance can 

 be made in our investigations. 



Some people suppose that the balance of the 

 body is maintained by a knee grip. This is not 

 the case. The balance of the body is maintained 

 in riding in a similar manner to walking or running, 

 which is by one's feet. 



Let us suppose a man is sitting loosely on the 

 back of a dogcart. Directly the horse springs 

 unexpectedly forward, he will find himself deposited 

 upon the ground. But if he anticipated the 

 forward movement, he will place his feet firmly 

 on the tailboard, and lean his body back (because 

 in this instance he is sitting with his back to the 

 horse). If he has done this, then when the jerk 

 occurs he will be able to maintain his seat without 

 disaster. This is merely an elementary law of 

 dynamics. 



Again, when a horse is trotting, cantering or 

 galloping at a uniform speed, the action, according 

 to the laws of motion, is similar to a man standing 

 on an open railway truck. If the train is pro- 

 gressing at a uniform rate, the man in the truck 

 has no problem to solve (apart from wind pressure). 

 But directly the train either slovv^s down or increases 

 its pace suddenly, then his difficulties become 

 apparent in exact proportion to the speed at which 

 the train is travelling and the amount of alteration 

 in that speed. If the train were travelling fast, 



