less in Magnitude, if not greater, (fome of them at leaft) than our Sun is, but only diminished in Appearance, by their prodigious Distances from us.

If now we reflect upon the prodigious Maffes of those many Heavenly Bodies that present themselves to our View (and many more I fhall fhew are unfeen) what a furprizing Scene do the Heavens afford us of the great CREATOR's Power! A Train of fuch immenfe Bodies, that what lefs than an Almighty Hand, could first find Matter fufficient for, and then compofe, fuch 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' confidered.

CHAP.

CHA P. III.

Of the IMMENSITY of the Heavens.

I

Tis neceffary that I should give a diftinct confideration to the immense Space possest by the Heavenly Bodies, because it was once imagined to be limited by the narrower Bounds of the Ptolemaic Syftem, by that which they called the 'ATλavís, the Starry Concameration, or Firmament of the fixt Stars, as I have before intimated; but now with far greater Probability and Reason, it is extended to an indefinitely larger Space, a Space fufficient, 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

I

Stars alfo. But for the better proof, and more eafy Apprehenfion of the Magnitude of this vaft expanded Space, let it be confidered,

1. That fome, if not every one, of those vaft Globes of the Universe have a Motion. This is, in fome, manifeft to our Sight; and may eafily be concluded of all, from the conftant 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 manifeft that the Earth is fet at fuch a due Distance from the Heavenly Bodies, and the Heavenly Bodies at fuch a due Distance from one another, as not to interfere, clash with, or disorder one another.

Nay

Nay fo great is their Distance, fo convenient their Situation, that they do not fo much as eclipfe one another, except fuch Planets as are called Secondary.

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

Now for the effecting of this, or any of the other Matters, it is neceffary that there be a fufficient Space. And that there is fuch, and what that Space is, we may make a Judgment of by confidering Particulars, according to the beft Obfervations 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 the Celestial Globes, but yet she takes up a Space of near 480

of

any

thou

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 fame thing) if the Sun revolves round the Earth, this Magnus Orbis, as it is ufually 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 Ifaac 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.

(b) Concerning the Distance between the Sun and the Earth, there is a great Difagreement between the former and latter Aftronomers, occafion'd by the Difagreement 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 feconds, and Riccioli but 28 feconds. Confequently the Distances arifing from hence are lefs than those of the

latter