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less in Magnitude, if not greater, (some of them at least) than our Sun is, but only diminished in Appearance, by their prodigious Distances

from us.

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If now we reflect upon the

prodigious Masses of those many Heavenly Bodies that present themselves to our View (and many more I shall shew are unseen) what a surprizing Scene do the Heavens afford us of the great CREATOR's Power! A Train of such immense Bodies, that what less than an Almighty Hand, could first find Matter fufficient for, and then compose, such Magnificent Works ! But yet what is the Magnitude of all these Bodies to that immense Space in which they are? Which is the next thing to be considered.

C H A P.

with far greater Probability and

CH A P. III. Of the IMMENSITY of the

Heavens. IT

T is necessary that I should give

a distinct consideration to the immense Space poffeft by the Heavenly Bodies, because it was once imagined to be limited by the narrower Bounds of the Ptolemaic System, by that which they called the Attravńs, the Starry Concameration, or Firmament of the fixt Stars, as I have before intimated; but now

Reason, it is extended to an indefinitely larger Space, a Space sufficient, without all doubt, to contain all the noble Variety of Systems therein ; not only our own of the Sun, but all those others I mentioned, of the fixt

Stars

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Stars also. But for the better proof, and more eafy Apprehension of the Magnitude of this vast expanded Space, let it be considered,

1. That some, if not every one, of those vast Globes of the Universe have a Motion. This is, in some, manifest to our Sight; and may eafily be concluded of all, from the constant Similitude and Consent that the Works of Nature have with one another. But in what manner these Motions are performed, whether by the Motion of the Heavenly Bodies round the Earth, or by the Earth round its own Axis, or any other way, it matters not much now to enquire.

2. It is manifest that the Earth is fet at such a due Distance from the Heavenly Bodies, and the Heavenly Bodies at such a due Distance from one another, as not to interfere, clash with, or disorder one another.

Nay

Nay so great is their Distance, so convenient their Situation, that they do not so much as eclipse one another, except such Planets as are called Secondary.

3. It is farther manifeft also, That those vast Bodies are so far off; as to appear extreamly small to our Eye, considering their prodigious Magnitudes.

Now for the effecting of this, or any of the other Matters, it is neceffary that there be a sufficient Space. And that there is such, and what that Space is, we may make a Judgment of by considering Patticulars, according to the best observations we have of these things.

And to begin nearest Home; the nearest of the Heavenly Bodies to us, is the Moon; whose Orb is the least of any of the Celestial Globes, but yet she takes up a Space of near 480

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thousand English Miles in Breadth (a) to perform her monthly Revolution in. And as for the Earth, if with the Moderns we suppose it, together with its Satellite the Moon, to revolve round the Sun; or (which amounts to the same thing) if the Sun revolves round the Earth, this Magnuus Orbis, as it is usually called, is a Space of above 540 Millions of Miles Circumference (b), or 172

Millions

(a) The Moon's mean Distance from the Earth, according to Sir Isaac Newton's Princip. p. 430. is 60 Semidiameters of the Earth, according to which the Diameter of the Moon's Orbit is 479905 English Miles.

(6) Concerning the Distance between the Sun and the Earth, there is a great Disagreement between the former and latter Astronomers, occafion'd by the Disagreement between their Obfervations of the Sun's Horizontal Parallax (which is equal to the Earth's Semidiameter viewed at the Sun) Tycho making it 3 minutes, Kepler but one, Bullialdus 2 minutes, 21 seconds, and Rice cioli but 28 seconds. Consequently the Distances arising from hence are less than those of the

latter

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