2b OF THE FIGURE AND MOTION

particular, which Astronomers have called thevisible world, or solar system.

By the universe we are to understand thewhole frame of nature, to the utmost extent osthe creation. And, by the solar system, ismeant that portion of the universe only, whichcomprehends the fun, planets, satellites, andcomets. Of this system the sun is supposed tobe the center; and it is now fully proved byAstronomers, that there are seven planetsmoving round him, each in its own path ororbit. The names of these planets, accordingto their distance from the center or middle pointof the fun, are, Mercury, Venus, the Earth,Mars, Jupiter, Saturn, and the Georgium Sidus.The two first, because they move within theearth’s orbit, are called inferior planets; and thefour last superior, from their moving withoutthe earth’s orbit.

Now if we can form a notion of the mannerin which our earth moves, we shall easily con-ceive the motions of all the rest of the planets,and by that means obtain a complete idea ofthe order and œconomy of the whole system.And, in order to this, nothing more is necessarythan to consider the common appearances ofthe heavens, which are constantly presented toour view, and attend to the consequences. Forsince it is well known that the fun and starsappear to move daily from east to west, and to

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