of the Earth fo much difputed againft and cavilled at as this; fo as even not long ago to have undergone the Cenfure of the Romish Church. However, because it seems very probable to many that there is such a Motion, we shall endeavour to explain it.

IT is known to all, even the Vulgar, that the Sun, Moon, and Stars, appear to move from East to Weft, and to return to almoft the fame Places again in the Heavens, in the Space of twenty four Hours. So that either they muft really move, or we our felves be moved; and attribute our Motion to them. For it is a felf-evident Principle, that if two Things change their Distance from one another, one of them, at least, must have moved.

THAT the Earth is fixed, or at Reft, and the Stars with the Heavens in Motion, was a common Opinion; and is fo ftill among thofe that are accounted Ptolemaic Aftronomers: But the Pythagoreans of old maintained, that the Stars conftantly kept their Places; and that the Earth was revolved about it's Center. Of which Sect was the celebrated Aristarchus of Samos; who, for defending this Opinion, was by his Enemy and Adverfary accused, before the Bench of the Areopagites, of having violated the Laws of Religion; but was fortunately abfolved by them *. Afterwards, but

for the difficulties of both of them, and fo is liable to feveral Objections in them both. He was very skillful in obferving, and in the Furniture of his Obfervatory exceeded even Princes and Kings.

John Kepler, the laft I fhall mention, by the help of Tycho's Labours, found out the Laws VOL. I

very

the Celeflial Bodies obferve in their Motion, and laid the Ground-work of the Modern Philofophy. Thus I have given a fhort Sketch of the Rife and Perfection of this Science.

*The Great Galilæo, the Modern Affertor of the fame Doctrine, met with the fate of the ancient Samian Philosopher; F

He

very few affented to this Opinion; fo that it lay hid, or, as it were, buried in Oblivion for many Ages; infomuch that we find not the least mention of it in the Schools, till the famous Aftronomer Copernicus, about 200 Years ago, brought it again into Estimation, and backed it with feveral Arguments, fo that many excellent Aftronomers after him embraced it; among whom flourished not long fince the great Kepler, Profeffor of Mathematics to the Emperor; and Galileo an Italian, Mathematician to the great Duke of Tuscany; as alfo Lanfberg a Dutchman.

AND whereas we obferve two apparent Motions in the Heavenly Bodies (one by which all the Stars both fixed and wandering feem to be carried about the Earth, and to rife to the Meridian, and fet under the Horizon nearly in the fame or equal Times: The other, which is called their Annual Motion; by which the Planets with different Motions, and the fixed Stars with equal Velocity, are carried the contrary Way from Weft to Eaft) the Ptolemaics affirm both thefe Motions to be in the Stars themselves, or in their Orbs But the Copernicans attribute this first apparent Motion to that real one of the Earth, not in being transferred from one Place to another, but to it's Rotation about it's Axis from Weft to Eaft, while it continues ftill in it's own Place (which caufeth the apparent Motion of all the Stars the contrary way). And they alfo free the Sun and the fixed Stars from the aforefaid annual Motion, by attri

He was brought before the Inquifition, and obliged folemnly to abjure his Aftronomical Tenets, that the Sun ftood immovable in the Midst of the Univerfe, and that the Earth moved round it, as about it's

;

proper Center. The poor Man was forced to fay, that he did, with a fincere Heart, and Faith unfeigned, abjure, curse, and deteft, the aforefaid Errors and Herefies.

buting the apparent Motion of these to the real annual Motion of the Earth round the Sun; and to the Inclination of it's Axis: Notwithstanding they affign this faid annual Motion to the rest of the Planets; only they deny the Sun to be a Planet, and advance him to the Center of the Syftem, where Ptolemy had placed the Earth; and make the reft of the Planets, Saturn, Jupiter, Mars, the Earth, Venus, and Mercury, revolve round him.

THE Reasons for the Copernican Hypothefis are these.

1. THE Motion of the Earth round it's Axis, continuing in the fame Place, will beft account for the Appearance of fuch a vaft Number of Stars which feem to perform their Revolutions round the Earth in 24 Hours; and therefore this Motion is most agreeable to Reafon: As it happens with us when we fit in a Ship, failing towards others at Reft in the Harbour; tho' they feem to approach and come nearer us, yet we do not affign that to any Motion in them. And as Nature never performs that by many means which may be done by a few; it is very likely the fame Rule is obferved here.

2. THE Motion of the Stars would thus be incredibly swift and beyond all Imagination; because their Distance, in Refpect of us, is almoft infinite, and the Orbit they have to run round fo prodigiously great, that they must move at least 100000 Miles in a Minute: On the other hand, if this Motion be affigned to the Earth, we need not introduce a progressive Celerity; for tho' fhe remains still in the fame part of Space, fhe folves the Phænomena by revolving about her Axis.

3. THIS Argument is the ftronger if we compare the vast Bulk of the Celestial Bodies with the Bulk of the Earth. For as the Sun is at least 200

SECT. II. times bigger than the Earth, and fome of the fixed Stars 1000 times; it is much more probable, that the Earth revolves round it's Axis with an easy natural Motion, than that fuch vaft Bodies fhould move from one Place to another with incredible Swiftnefs.

4. THE moft celebrated Aftronomers are, with Tycho, forced, by the Phænomena, to deny that there are folid Orbs, fuch as the Ancients made use of the better to explain their imaginary Motion of the Stars; hence their Arguments for this diurnal Rotation about the Earth, are lefs cogent. The Reason why they are forced to deny this, is, because that one Planet is often feen within the Orb of another; which must cause a mutual Penetration.

5. NO Reason can be given why the Stars fhould move round the Earth: But, on the other hand, it is most agreeable to Reason, that the Earth, and the reft of the Planets, fhould move about the Sun.

6. NEITHER the Pole nor the Axis about which the Stars are fuppofed to revolve, is real: On the contrary, there is a known Pole and Axis in the Earth.

7. FOR this Reafon alfo Navigation is much eafier from Weft to Eaft than the contrary Way. For they can fail from Europe to India in about four Months; but can scarce return in fix Months: because in their going they move to the fame Point with the Earth; but in their returning they steer contrary to the Earth's Motion.

8. BECAUSE the Celestial Phænomena, fuch as the rifing and fetting of the Stars, the Inequality of Days, &c. cannot be accounted for, by any other Motion than that of the Earth. And the Commodioufnefs and Neceffity of this Hypothefis, is more particularly perceived in the wonderful Appearances

pearances of the Planets; for explaining of which the Ptolemaics are forced to fuppofe feveral unneceffary interfering Circles, Epicycles, and Eccentrics, without any Reafon: Whereas the Copernicans can naturally account for them all, (without any previous Suppofitions,) by the annual Motion of the Earth, or it's Revolution round the Sun, viz. 1. Why the Planets feem fometimes retrograde; and why Saturn is oftener and continues longer fo than Jupiter; and Jupiter oftener and longer fo than Mars, &c. and alfo why they are carried fometimes with a swifter Motion, and at other times appear ftationary. 2. Why Mercury and Venus can never be feen a whole Night together. 3. Why Venus is never carried further from the Sun than 48 degr. and Mercury never more than 28; and fo can never be feen in Oppofition to the Sun. 4. Why Venus may be seen in the Evening after the Sun is fet; and the next day in the Morning before the Sun rifes, &c.

I FORBEAR to mention any more Phænomena, (these being the principal from whence a folid Argument may be drawn for the Motion of the Earth) fince they are all easily and naturally accounted for upon this Hypothefis; fo that it would be ftrange if the Earth fhould not move, when fuch evident Appearances require fuch a Motion. And tho' thefe Arguments are not demonftrative, yet they render this Hypothefis preferable to the other, which fuppofeth the Motion of the Heavens. And we must admit of the one or

the other..

BUT the Arguments which fome alledge to the contrary are eafily answered; fuch as, 1. The Earth is not fit for Motion, because of it's Gravity. 2. The Parts of the Earth naturally tend in a right Line to the Center; and therefore a circular Motion is against Nature. 3. If the Earth