152 THE THEORY OF THE BICYCLE. 
C. Now incase of a bicyclist, his forward motion is at 
right angles to gravity, hence does not in any way resist 
it, and therefore, as it is gravity that causes him to tilt 
over, the forward motion will not prevent his falling. 
But it may be said that the force of quality is in fact 
resolved into two components, one vertical, and the 
other horizontal, and that it is only the latter that 
causes the ’cyclist to fall. This does not affect our con- 
clusion, for both components are perpendicular to the 
‘course of the bicycle, and hence its forward motion can 
in no way counteract either of them. 
Unless, therefore, some other force beside his forward 
movement comes into action, the ‘cyclist must fall to- 
wards which ever side he happens to begin to lean. 
Many think they find this in ‘‘Centrifugal Force.”? You 
are all familiar with the effects of this so called force. 
You feel them every time you turn a corner quickly, 
whether on foot, in a wagon or on horse back. The 
bare-back riders in the circus lean well towards the 
centre of the ring to escape being thrown outward. 
We see its effect when the ’cyclist spins around a 
corner. In this case ‘‘centrifugal force’’ plays an im- 
portant part and is the real upholding force. But centri- 
fugal force is impossible, so long as the body moves in 
one direction. Other things being equal, it is greater 
in proportion to the abruptness of the change, or as 
mathematicians say, the centrifugal force, so long as the 
velocity is uniform, varies inversely as the radius of the 
curve in which the body moves. If that is very large, 
the centrifugal force will be very small. If the radius 
of curvature becomes infinite, 7. e., if the curve becomes 
a straight line, the centrifugal force becomes infinitely 
small, or zero. So long, therefore, as the bicyclist does 
not turn any corners—keeps in a straight course—the 
‘‘centrifugal force’’ gives no assistance, whatever, in 
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