THE GYROCAR 



within the kind of frames or hoops called gimbals, if 

 you can secure such a one, will show you the same 

 phenomenon ; it will resist having its axis diverted from 

 the direction it chanced to have when it was set spinning. 



If you ask why the spinning wheel exerts this power, 

 it may not be easy to give an answer. The simplest 

 things are hardest to explain. No man knows why and 

 how gravitation acts ; no one knows why a body at rest 

 tends always to remain at rest until some force is applied 

 to it; nor why when a body is once in motion it tends 

 always to move on at the same rate of speed until some 

 counter-force stops it. Such are the observed facts; 

 they are facts that underlie all the principles of mechan- 

 ics; but they are matters of observation, not of ex- 

 planation or argument. And the fact that a revolving 

 body tends to maintain its axis in a fixed position is a 

 fact of the same category. 



So far as we can explain it at all, we may, perhaps, 

 say that the inertia which the matter composing the 

 wheel shares with all other matter is accentuated by 

 the fact that its whirling particles all tend at successive 

 instants to fly in different directions under stress of 

 centrifugal force. At any given instant each individual 

 particle tending to fly off in a particular direction may be 

 likened to a man pulling at a rope in that direction. 



If you imagine an infinite number of men circled 

 about a pole to which ropes are attached, and evenly 

 distributed, each one pulling with equal force, it will 

 be clear that the joint effort of the multitude would 

 result in fixing the pole rigidly at the centre. The 

 harder the multitude pulled, so long as they remained 



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