What we call a vortex is a quantity of matter, whose detached parts move all in the same direction, but allowed at the same time to have some little movements peculiar to themselves, provided they still pursue the general course. A vortex of wind, for instance, is a vast number of little particles of air, turning all together in a circular direction, and involving whatever comes in their way. The planets you know are borne along by the celestial fluid, which is prodigiously subtle and active. All the celestial matter, from the sun to the fixed stars, constantly turns round, carries the planets along with it, and makes them proceed round the sun in the same direction, but in longer or shorter periods, according to their distance from the centre. Even the sun is made to turn on his axis by being exactly in the midst of this moving matter; you will therefore observe, that if the earth were in the central situation she could not be exempted from this rotation. Such is the great vortex of which the sun is master; but the planets, at the same time, form little vortices in imitation of the sun. Each of them whilst turning round the sun, turns likewise on itself, and carries in its motion a certain portion of the celestial matter, which is ready to receive any impulse that would not prevent it from following the general course: this is a vortex of any particular planet, and it extends as far as the motion of this planet has any influence. If a smaller planet comes within the vortex of a larger one, it is irresistibly carried round that larger one, and altogether, the large, and the small planet, and the vortex that encloses them, perform their revolution round the sun. Thus at the commencement of creation we obliged the moon to follow us because she came within the influence of our vortex, and was by that mean subjugated to our will. Jupiter, the planet we were speaking of, was more fortunate, or more powerful than the earth. Four little planets were in his neighbourhood, and he became master of them all; and we, who are a planet of some importance, would probably have felt his power if we had been near him. He is a thousand times larger than the earth;[38] and would easily have drawn us into his vortex, and made us one of his moons; instead of this we have a planet to attend on us: so true is it that the situation into which we are thrown decides the fate of our lives. [Footnote 38: We may even say thirteen hundred times.]