Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 1.djvu/340

 through its own centre and the centre to which the force is directed; that force will always urge each hemiphere equally; and therefore will not incline the globe any way as to its motion round its own axis. But let there be added any where between the pole and the æquator a heap of new matter like a mountain, and this by its perpetual endeavour to recede from the centre of its motion, will diturb the motion of the globe, and caue its poles to wander about its uperficies, decribing circles about themelves and their oppoite points; Neither can this enormous evagation of the poles be corrected, unles by placing that mountain either in one of the poles, in which cae by cor. 21. the nodes of the æquator will go forwards; or in the equatorial regions, in which cae by cor. 20. the nodes will go backward; or latly by adding on the other ide of the axis a new quantity of matter, by which the mountain may be balanced in its motion; and then the nodes will either go forwards or backwards. as the mountain and this newly added matter happen to be nearer to the pole or to the equator.

The ame laws of attraction being uppoed, I ay that the exterior body S does, by radii drawn to the point O, the common centre of gravity of the interior bodies P and T, decribe round that centre areas more proportional