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Nature's high Birth her heav'nly Beauties fhow,
By ev'ry Feature we the Parent know.
Th' expanded Spheres, amazing to the Sight,
Magnificent with Stars and Globes of Light;

The glorious Orbs which Heav'n's bright Hoft compofe,
The imprifon'd Sea, that reflefs ebbs and flows;
The fluctuating Fields of liquid Air,

With all the curious Meteors bov'ring there,
And the wide Regions of the Land proclaim,
The Pow'r divine that rais'd the mighty Frame,

Creation. Pag. 5.

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Of the UNIVERSE, and the feveral SYSTEMS of the WORLD.

Cleonicus.

I Guefs at Sifter, terminates

in a fair and delightful Evening, which invites us to the Pleasures of a Walk; you are ready to go, but which Way are you inclined to take, the Park or the Fields, or along the winding Lanes ?

Eupbrofyne. The Park, this Evening, if you chufe it, Brother.

Cleon. With all my Heart, Euphrofyne; come on, and while we take a Tour about the large extended Plain, ask me any Questions your Curiofity may fuggeft, and I'll endeavour to anfwer them the best I can.

Euphrof. I thank you, Cleonicus; I remember when we laft difcourfed together, you promised nie a regular Account of natural Things, and faid we fhould begin with the Heavens; this feems an ambiguous Term to me; pray, what do the Philofophers mean by the Heavens?

Cleon. They fometimes mean the Sky or Firmament; fometimes the Orbits of the Planets; fometimes the Space of one Syftem; and fometimes of all the Systems in the Universe.

Euphrof. That I may have a yet clearer Idea of what you intend, I must beg you to explain the Terms, Univerje, B 4 Syftems,

Syftems, Space, &c. for I would willingly understand Things aright.

Cleon. By the Universe, my Euphrofyne, you are to understand the whole Creation of all Things, together with the every Way infinitely extended Space or Void in which they have their Existence.

Euphrof. If, as you intimate, the Universe be infinite, how do you think it is furnished in the several Parts thereof, or is it all an empty Place beyond the Stars.

Cleon. The Philofophers of the prefent Age teach us, that the Universe through all the boundlefs Space, is replenished with Systems or Worlds of different Bodies. For by a Syftem, they mean a Number of Bodies which move about one common Centre or Point; and such a System is what we call a World; and the moving Bodies of these Systems, we call Planets and Comets in ours.

Euphrof. Do the Philofophers know any Thing of the feveral Systems or Worlds befides our own?

Cleon. Not any Thing certainly; they only make probable Conjectures at most, and reason from the Analogy they obferve between fome Things in our Syftem, and fome in theirs, which they think alike; of which I shall be more particular when we talk of the Stars.

Euphrof. You know beft, dear Cleonicus, how to direct my Enquiries; I am content therefore if I can but obtain a general Knowledge of our own World; but what did you fay, that all the Bodies of our World were moveable about a Center?

Cleon. Yes, all but one; and that one is it which poffeffeth the Center or middle Point of the Syftem, nearly.

Euphrof. Before I can ask you a Question I intend, you muft, Cleonicus, tell me how many Bodies there are which compofe our Syftem or World?

Cleon. Thofe whofe Number is certain are, of the larger Sort, Six; viz. Mercury, Venus, the Earth, Mars, Jupiter, and Saturn, befides the Sun, which is far greater than them all. But thofe Bodies we call Comets, or Blazing-flars, are ftill more, tho' uncertain in Number. Befides all these, there is a leffer Sort of Bodies in our Syftem which move about the larger, and they are called Satellites or Moons, of which we can fee but one with the naked Eye.

Euphrof. But, dear Cleonicus, are not the Stars which

twinkle

twinkle all about us, and light us through gloomy Nights, a Part of our System?

Cleon. No; the Reafon of which you will understand by-and-by.

Euphraf. Then the Question I would ask, is; which of all thofe Bodies you mention is that which remains at rest in the Center of the Syftem?

Cleon. That is the Question, indeed; you will not a little wonder, perhaps, to hear, that the most learned Philofophers have been controverting this Point for above 2000 Years; Schools have difputed with Schools; and many and different Systems have been formed to folve the Appearances and Motions of the heavenly Bodies.

Euphrof. I have read, I remember, of the Systems of Ptolomy, Tycho, and Copernicus; I fuppofe you mean these among the reft; do you not, Cleonicus?

Cleon. Yes, my Euphrofyne, thofe which you mention are the principal; befides which there were fome others, as of Kepler, Defcartes, &c. from such a Variety of Notions, Sir Richard Blackmore says,

The old and new Aftronomers in vain

Attempt the heav'nly Motions to explain.

But here Sir Richard was mistaken; for the new Aftronomers have very fuccefs fully explained the heavenly Motions in every Respect.

Euphrof. Tho' it may not be to much Purpose to have a large Account of all these Systems, yet I fhould be glad juft to know what they were, and how they differed from each other, in as few Words as you can.

Cleon. The Syftem of the famous Egyptian Aftronomer, Ptolomy, was the most grofs and vulgar: He supposed the Earth poffeffed the Center of the World, and that about it moved, firft the Moon, then Mercury, then Venus; then the Sun, then Mars, Jupiter and Saturn; all in Orbs above each other; next above Saturn he placed the Firmament of the fixed Stars; and above thefe, two folid crystalline Spheres, one moving from Eaft to Weft, the other from North to South, and vice verfâ. All these he included in that Sphere he called the Primum Mobile, or firft Mover, which, by a daily Motion about it's Axis, carried the inferior Orbs from East to Weft once in 24 Hours. But

this Hypothefis was far from folving the Appearances of the heavenly Motions, and therefore is defervedly thus cenfured by the aforefaid Gentleman.

First Ptolomy his Scheme celeftial wrought,
And of Machines a wild Provifion brought..
Orbits centric and eccentric he prepares,
Cycles and Epicycles, folid Spheres,

In Order placed, and with bright Globes inlaid,
To folve the Tours by heavenly Bodies made.
But fo perplex'd, fo intricate a Frame,

The later Ages with Derifion name.

This System you have represented in the Diagram I have drawn for you (Plate I. Fig. 1.) and is evident by Inspection only.

Euphrof. It is fo; it is the Figure of the Heavens, which I have seen in every common Map. But fince Tycho difapproved of Ptolomy's System, I fuppofe he advanced one more plaufible; pray, what was peculiar to his?

Cleon. 'Tis faid, he placed the Earth in the Center of the System, and gave it only a diurnal Motion about its Axis once in 24 Hours; tho' fome fay, he made the Earth to be abfolutely at reft. About the Earth he revolved the Moon, and alfo the Sun, but then about the Sun he placed the Orbs of Mercury, Venus, Mars, Jupiter and Saturn; fo that they revolve at the fame Time about the Earth once in a Year. Thus Sir Richard:

The famous Dane, who oft the Moderns guides,
To Earth and Sun their Provinces divides;
The Earth's Rotation makes the Night and Day;
The Sun, revolving thro' the ecliptic Way,
Effects the various Seafons of the Year:

Which, in their Turn, for happy Ends appear.

This enormous Conftruction of a System of the World I have represented alfo in a Scheme, for your more easy apprehending it (Fig. 2.)

Euphrof. I am obliged to you for it, as it is not quite fo eafy to get an Idea of it without. This Scheme of the Heavens, if I remember right, is also exploded; but I forget the particular Reasons thereof.

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