1the obſervators ſtanding in Jupiter, make the ſelf ſame changes
of Figure, that to us upon the Earth, the Moon doth make. You
ſee now how theſe three things, which at ſirſt ſeémed diſſonant,
do admirably accord with the Copernican Syſteme. Here alſo by
the way may Simplicius ſee, with what probability one may
clude, that the Sun and not the Earth, is in the Centre of the
Planetary converſions. And ſince the Earth is now placed
mongſt mundane Bodies, that undoubtedly move about the Sun,
to wit, above Mercury and Venus, and below Saturn, Jupiter,
and Mars; ſhall it not be in like manner probable, and perhaps
neceſſary to grant, that it alſo moveth round?
of Figure, that to us upon the Earth, the Moon doth make. You
ſee now how theſe three things, which at ſirſt ſeémed diſſonant,
do admirably accord with the Copernican Syſteme. Here alſo by
the way may Simplicius ſee, with what probability one may
clude, that the Sun and not the Earth, is in the Centre of the
Planetary converſions. And ſince the Earth is now placed
mongſt mundane Bodies, that undoubtedly move about the Sun,
to wit, above Mercury and Venus, and below Saturn, Jupiter,
and Mars; ſhall it not be in like manner probable, and perhaps
neceſſary to grant, that it alſo moveth round?
The Medicean
Stars areas it were
four Moons about
Jupiter.
Stars areas it were
four Moons about
Jupiter.
SIMP. Theſe accidents are ſo notable and conſpicuous, that
it is not poſſible, but that Ptolomy and others his Sectators, ſhould
have had knowledge of them, and having ſo, it is likewiſe
ſary, that they have found a way to render reaſons of ſuch, and
ſo ſenſible appearances that were ſufficient, and alſo congruous
and probable, ſeeing that they have for ſo long a time been
ceived by ſuch numbers of learned
it is not poſſible, but that Ptolomy and others his Sectators, ſhould
have had knowledge of them, and having ſo, it is likewiſe
ſary, that they have found a way to render reaſons of ſuch, and
ſo ſenſible appearances that were ſufficient, and alſo congruous
and probable, ſeeing that they have for ſo long a time been
ceived by ſuch numbers of learned
The Principal
ſcope of
mers, is to give a
reaſon of
ances.
ſcope of
mers, is to give a
reaſon of
ances.
SALV. You argue very well; but you know that the principal
ſcope of Aſtronomers, is to render only reaſon for the appearances
in the Cæleſtial Bodies, and to them, and to the motions of the
Stars, to accomodate ſuch ſtructures and compoſitions of Circles,
that the motions following thoſe calculations, anſwer to the ſaid
appearances, little ſcrupling to admit of ſome exorbitances, that
indeed upon other accounts they would much ſtick at. And Co-
ſcope of Aſtronomers, is to render only reaſon for the appearances
in the Cæleſtial Bodies, and to them, and to the motions of the
Stars, to accomodate ſuch ſtructures and compoſitions of Circles,
that the motions following thoſe calculations, anſwer to the ſaid
appearances, little ſcrupling to admit of ſome exorbitances, that
indeed upon other accounts they would much ſtick at. And Co-
pernic us himſelf writes, that he had in his firſt ſtudies reſtored the
Science of Aſtronomy upon the very ſuppoſitions of Ptolomy, and
in ſuch manner corrected the motions of the Planets, that the
computations did very exactly agree with the Phænomena, and
the Phænomena with the ſupputations, in caſe that he took the
Planets ſeverally one by one. But he addeth, that in going
bout to put together all the ſtructures of the particular Fabricks,
there reſulted thence a Monſter and Chimæra, compoſed of
bers moſt diſproportionate to one another, and altogether
patible; So that although it ſatisfied an Aſtronomer meerly
rithmetical, yet did it not afford ſatisfaction or content to the
Aſtronomer Phyloſophical. And becauſe he very well
ſtood, that if one might ſalve the Cæleſtial appearances with falſe
aſſumptions in nature, it might with much more eaſe be done by
true ſuppoſitions, he ſet himſelf diligently to ſearch whether
ny amongſt the antient men of fame, had aſcribed to the World
any other ſtructure, than that commonly received by Ptolomy;
and finding that ſome Pythagoreans had in particular aſſigned
the Diurnal converſion to the Earth, and others the annual
tion alſo, he began to compare the appearances, and