82 



WELLS'S NATURAL PHILOSOPHY. 



ring this inclination of his body is imperceptible ; if he trot, there is a visible 

 inclination inward, and if ho gallop, ho inclines still more, and when urged to 

 full speed he leans very far over on his side, and his feet will be heard to 

 strike against the partition which defines the ring. The explanation of all 

 this is, that the Centrifugal Force caused by the rapid motion around the 

 ring tends to throw the horse out of; and away from, the circular course, and 

 this ho counteracts by leaning inward. 



Fig. 65. 



How do tha 



motions of the 

 Bolar system il- 

 lustrate the ac- 

 tion of Centri- 

 fugal and Cen- 

 tripetal Forces T 



The most magnificent exhibition of Centrifugal and Centri- 

 petal Forces balancing each other, is to be found in the ar- 

 rangements of the solar system. The earth and other planets 

 are moving around a center — the sun, with immense veloci- 

 ties, and are constantly tending to rush off into space, by the 

 action of the Centrifugal Force. They are, however, restrained 



within exactly determined limits by the attraction of the sun, which acts 



as a centripetal power drawing them toward the center. 



What is the 168. The Axis of a body is the straight line, 

 Axisof a body? j.g^| ^^ imaginary, passing through it, on which 

 it revolves, or may revolve. 



169. When a body rotates upon an axis, all 

 its parts revolve in equal times. The velocity 

 of each particle of a revolving body increases 

 with its perpendicular distance from the axis, 

 and as its velocity increases, its Centrifugal Force in- 

 creases. 



A moment's reflection will show, that a point on the outer part, or rim, of 

 a wheel, moves round the axis in the same time as a point nearer the center, 

 «a upon the hub. But the circle described by the revolution of the outer part 



Whpn a body 

 ri'.YcAveB round 

 its Axis, what 

 peculiarities 

 do its several 

 parts exhibit t 



