Peripateticall institutions. In the way of that eminent person and excellent philosopher Sr. Kenelm Digby. The theoricall part. Also a theologicall appendix of the beginning of the world. / By Thomas White Gent.

LESSON XIV.

Of the Motion of the Earth, and the Causes of it.

1. SInce, therefore, the upper part of the water is continually mov'd to∣wards the West: (and, as, because the water in the middle runs one way, that by the Shore-side must needs run backwards; so also, because the supe∣riour water is hurry'd towards the West,) that which is next under it must needs be driven back to the East, and whatever so adheres to it that there is no cause of separation; that is, which will easilyer be driven towards the East then be separated from the lower water.

2. But, one part of the lower water is not separable from another, unlesse it ei∣ther ascends into the place of that above it, which another part, supervening, pre∣vents and hinders; or else, unlesse it re∣pells that which is Easternly to it, and that again another, and, in the end, the last, the Shore that's oppos'd against it, which

is incredible and impossible: The whole body, therefore, with the Earth ad∣hering to it, must needs be driven to∣wards the East, unlesse there be some resistance stronger then the impulse.

3. Whereof ther's none in its gravity, because that motion is not contrary to the motion of gravity; and its bignesse even much facilitates the motion: The Earth, therefore, will be mov'd in a Circle, and turn round about its own Cen∣tre, because this impulse is made in a Cir∣cle.

4. Again, because 'tis almost impossi∣ble this impulse should be equall on all sides, and cause a pure rotation about the Centre; there will, of necessity, a Progressive motion be mixt with it.

5. And since, as a body cannot be, but in one place, so neither can it move but in one line: all the motions which Astronomers assign the Earth must, of necessity, compose one line; and, if the lashing or impulse of the under-wa∣ter advance the Earth in that line, 'twill be an adequate cause of the motion of the Earth.

6. Now, Astronomers teach, that the Earth, continually turning about its own

Centre, runs under the Zodiack; its Axis retaining a certain inclination to the Axis of the Zodiack: wherefore, when we have found out a line, in which the Earth, being thrust on, will observe this motion; the Flux must be imagin'd to move the Earth according to that.

7. Astronomers prove these motions of the Earth: because, otherwise, greater motions of greater bodies must be sup∣pos'd; and those, neither themselves con∣stant, nor proportion'd to the bodies, and, besides, more entangled, both in the Stars and in the Sun it self, as is apparent by its Spots: Which if you say make not up a perfect Astronomicall Demonstration, that Maxime must be renounc'd upon which all Astronomy depends, viz. that the Pheno∣mena (or appearances) are to be solv'd the best way we can.

8. Again; because there follows a varie∣ty in the fixed stars, from the diversity of the Earth's position in its Orbis Magnus; when there's once found out a Telescope, of such perfection as to be able to distinguish that variety, we may expect a Geometricall Demonstration: and because, for the same reason, there must needs be a variety of re∣flection from Mars and Iupiter; when the

laws & rules of light shall be better known, there will not want a Physicall Demonstra∣tion.