through its own centre and the centre to which the force is directed; that force will always urge each hemiſphere 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 diſturb the motion of the globe, and cauſe its poles to wander about its ſuperficies, deſcribing circles about themſelves and their oppoſite points; Neither can this enormous evagation of the poles be corrected, unleſs by placing that mountain either in one of the poles, in which caſe by cor. 21. the nodes of the æquator will go forwards; or in the equatorial regions, in which caſe by cor. 20. the nodes will go backward; or laſtly by adding on the other ſide 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.
Proposition LXVII. Theorem XXVII.
The ſame laws of attraction being ſuppoſed, I ſay 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, deſcribe round that centre areas more proportional
