6 OEBITAL MOTION AND CENTRIFUGAL FORCE. 



tends to move a fluid towards those parts of any 

 body which, being most remote from any axis of 

 rotation, move with the greatest velocity. 



164. It will be observed that we here simply 

 maintain that the orbital motion of the earth 

 cannot give rise to a centrifugal force analogous to 

 that which results from the axial rotation of the 

 earth. And if, as we have remarked in section 15 

 in vol. i., by any possible mode of actipn such as 

 an innate and constant tendency of the earth to fly 

 off at a tangent from its orbit centrifugal force 

 be the power which counteracts the force of solar 

 gravitation, then must the counter-tides raised by 

 that force be, of necessity, so nearly similar to such 

 as would result from the action of counter-attraction 

 proceeding from astral gravitation, that we must 

 look elsewhere for such facts as may determine which 

 of these forces it is that maintains the equilibrium of 

 the solar system. 



165. We there also suggested that, if the position of 

 the earth and the direction of its motions be entirely 

 controlled by gravitation discarding centrifugal 

 force, which is rendered requisite solely by the 

 assumption that the earth moves by virtue of an 

 innate tendency to motion in a straight line, or 

 from the effect of a primary impulse given in a 

 straight line if, as we have just said, the position 

 and motion of the earth be determined by gravitation, 

 then there should be a tendency to the formation 



