Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 1.djvu/37

Rh no manner of perturbation in o many ages from the actions of the conflicting matter. Certainly if thee fictitious motions are more compounded and more hard to be accounted for than the true motions of the Planets and Comets, it eems to no purpoe to admit them into philoophy; ince every caue ought to be more imple than its effects. Allowing men to indulge their own fancies, uppose any man hould affirm that the Planets and Comets are urrounded with atmopheres like our Earth; which hypotheis eems more reaonable than that of vortices. Let him then affirm that thee atmopheres by their own nature move about the Sun and decribe conic ections, which motion is much more eaily conceived than that of the vortices penetrating each other. Latly, that the Planets and Comets are carried about the Sun by thee atmopheres of theirs; and then applaud his own agacity in dicovering the caues of the celetial motions. He that rejects this fable mut alo reject the other; for two drops of water are not more like than this hypotheis of atmopheres, and that of vortices.

Galileo has hewn, that when a tone projected moves in a parabola, its deflexion into that curve from its rectilinear path is occaioned by the gravity of the tone towards the Earth, that is, by an occult quality. But now ome body, more cunning than he, may come to explain the caue after this manner. He will uppofe a certain ubtile matter, not dicernable by our ight, our touch or any other of our enes, which fills the paces which are near and contiguous to the uperficies of the Earth; and that this matter is carried with different directions, and various, and often contrary, motions, decribing