round, containing the Earth in the midst of it. And by Pliny's account (b) of Pythagoras his Distances, and Orders of the Planets, this seems to have been his opinion. But the fame Laertius (c) affirms Philolaus the Pythagorean, Tỉv Tạonvé a nemi Kóxλον, πρώην ειπείν δι 3, Ικάταν Συρακόστον φασιν to have been the first that said the Earth was moved in a Circle : but some Jay Hicetas the Syracusian. So Plum tarch, in his Life of Numa, speaking of Numa's building the Temple of Vesta, faith, he built it round, and that a continual Fire was kept therein, in imitation of the Figure of the Earth, or rather of the whole World itself, the middle of which the Pythagoreans (not

Pythagoras) take to be the Seat

of Fire.

This System (whợever was the Inventer of it) Copernicus a Canon

(6) Nat. Hist. L. 2. c. 21, 22. (c) Ibid, in Philolao,


of Tourain restored about the beginning of the fifteenth Century, and was followed therein by many considerable Men, as Rheticus, Mostlinus, Kepler, Rothman, Bullialdus, Lanberge, Herigonius, Schickard, Gassendus, Galilæo, and others. The last of which (by the ill will and instigation of Pope Urban VIII. as 'tis supposed) had the misfortune to fall under the censure of, and to have his Copernican Tenets condemned by the Inquisition, and was forced to abjure them. The particulars of which, if the Reader hath a inind to see, he may find them in Riccioli's Almagest (d).

According to this system, the Sun is supposed to be in the Center, and the Heavens and Earth to revolve round about him according to their. several Periods : First, Mercury in


(d) Lib. 9. Sect. 4. Cap. 40.


near 88 Days; then Venus in somewhat above 224 Days ; then the Earth with its Satellite the Moon, in 365 Days; then Mars in about 687 Days ; then Jupiter with his four Moons in about 4333 Days; and lastly, Saturn in somewhat above 10759 Days, with his 5 or more Moons re

5 volving about him.

And beyond, or above all these, is the Firmament, or the Region of the Fixt Stars, which are all supposed to be at equal distanccs from their Centre the Sun.

This is the Copernican System, which I have given a Scheme of in Fig. 2. And so far as this System relates to the Motion of the Earth, and the Sun resting in the Centre, I prefer it to the

Ptolemaick Hypothesis on these Five following accounts:

1. Because it is far more agreeable to Nature, which never goes a


round-about way, but always acts by the most compendious, easy and simple methods. And in the Copernican way, that is performed by one,

, or a few easy Revolutions, which, in the other way, is made the work of the whole Heavens, and of many strange and unnatural Orbs. Thus the Diurnal Motion is accounted for by one Revolution of the Earth, which all the whole Heavens are called in for, in the other way ; So for the Periodical Motions of the Planets, their Stations, Retrogradations and direct Motions, they are all accounted for by one easy, single Motion round the Sun, for which, in the Ptolemaick way, they are forced to invent divers strange, unnatural, interfering Eccentricks and Epicycles : An Hypothesis so bungling and monstrous, as gave occasion to a certain King to say, If he had been of God's Council when he made



the Heavens, he could have taught him how to have mended his Work.

2. As the Copernican is far more easy and agreeable to Nature than the Ptolemaick System, so it is far more complete, and answerable to the various Phænomena of the Planets ; several of which the Ptolemaick Hypothesis either very aukwardly folves, or doth not at all come up to. I might instance here in divers particulars relating to Venus and Mercury, as why the Earth is never between them and the Sun, which the Ptolemaick System gives no tolerable account of, and but poor accounts of other of their Phænomena, as also of those of the Moon and the other Planets. I might shew also how incoherent and improper the Motions assigned to the Heavenly Bodies are in the Ptolemaick way, as that the Moon should move round once in a Month, the other 3


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