Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/259

 produceth sundry and divers motions in living creatures. And as to the flexures there is no need of them, the motions being of the whole, and not of some particular parts; and because they are to be circular, the meer spherical figure is the most perfect articulation or flection that can be desired.

The most that ought to be granted upon this, would be, that it may hold true in one single motion, but in three different motions, in my opinion, and that of the Author, it is impossible; as he going on, prosecuting the objection, writes in the following words. Let us suppose, with Copernicus, that the Earth moveth of its own faculty, and upon an intrinsick principle from West to East in the plane of the Ecliptick; and again, that it also by an intrinsick principle revolveth about its centre, from East to West; and for a third motion, that it of its own inclination deflecteth from North to South, and so back again. It being a continuate body, and not knit together with joints and flections, our fancy and our judgment will never be able to comprehend, that one and the same natural and indistinct principle, that is, that one and the same propension, should actuate it at the same instant with different, and as it were of contrary motions. I cannot believe that any one would say such a thing, unlesse he had undertook to maintain this position right or wrong.

Stay a little; and find me out this place in the Book. Fingamus modo cum Copernico, terram aliqua suâ vi, & ab indito principio impelli ab Occasu ad Ortum in Eclipticæ plano; tum rursus revolvi ab indito etiam principio, circa suimet centrum, ab Ortu in Occasum;tertio deflecti rursus suopte nutu à septentrione in Austrum, & vicissim. I had thought, Simplicius, that you might have erred in reciting the words of the Author, but now I see that he, and that very grossely, deceiveth himself; and to my grief, I find that he hath set himself to oppose a position, which he hath not well understood; for these are not the motions which Copernicus assignes to the Earth. Where doth he find that Copernicus maketh the annual motion by the Ecliptick contrary to the motion about its own centre? It must needs be that he never read his Book, which in an hundred places, and in the very first Chapters affirmeth those motions to be both towards the same parts, that is from West to East. But without others telling him, ought he not of himself to comprehend, that attributing to the Earth the motions that are taken, one of them from the Sun, and the other from the primum mobile, they must of necessity both move one and the same way.

Take heed that you do not erre your self, and Copernicus also. The Diurnal motion of the primum mobile, is it not from