Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 1.djvu/39

Rh in all the matter contiguous to the perimeter of the magnus orbis, mut be of the ame denity as the Earth. But now that which lies between the magnus orbis and the orb of Satum mut have either an equal or greater denity. For to make the contitution of the vortex permanent, the parts of les denity mut he near the centre, and thoe of greater denity mut go farther from it. For ince the periodic times of the Planets are in the equiplicate ratio of their ditances from the Sun, the periods of the parts of the vortices mut alo preerve the ame ratio. Thence it will follow that the centrifugal forces of the parts of the vortex mut be reciprocally as the quares of their ditances. Thoe parts therefore which are more remote from the centre endeavour to recede from it with les force; whence if their denity be deficient, they mut yield to the greater force with which the parts that lie nearer the centre endeavour to acend. Therefore the dener parts will acend; and thoe of les denity will decend; and there will be a mutual change of places, till all the fluid matter in the whole vortex be o adjuted and dipoed, that being reduced to an equilibrium its parts become quiecent. If two fluids of different denity be contained in the ame veel; it will certainly come to pas that the fluid of greater denity will ink the lowet; and by a like reaoning it follows that the dener parts of the vortex by their greater centrifugal force will acend to the highet places. Therefore all that far greater part of the vortex which lies without the Earth's orb, will have a denity, and by conequence a vis inertia anwering to the bulk of the matter, which cannot be les than the denity and vis inertia of the Earth. But from