Archimedes Texts

416
to all the Stars, as is this diurnal one: yet I believe that in few
dayes they perceived that the Moon was inconstant in keeping
company with the other Stars; but yet withal, that many years
past, before that they distinguished all the Planets: And in par
ticular, I conceit that Saturn by its slowness, and Mercury by rea

son of its seldom appearing, were the last that were observed to
be wandring and errant. It is to be thought that many more
years run out before the stations and retrogradations of the three
superiour Planets were known, as also their approximations and
recessions from the Earth, necessary occasions of introducing the
Eccentrix and Epicicles, things unknown even to Aristotle, for
that he makes no mention thereof. Mercury, and Venus, with
their admirable apparitions; how long did they keep Astrono
mers in suspence, before that they could resolve (not to speak of
any other of their qualities) upon their situation? Insomuch
that the very order onely of the Mundane bodies, and the inte
gral structure of the parts of the Universe by us known, hath been
doubted of untill the time of Copernicus, who hath at last given
us notice of the true constitution, and real systeme, according to
which those parts are disposed; so that at length we are certain
that Mercury, Venus, and the other Planets do revolve about
the Sun; and that the Moon revolveth about the Earth. But

how each Planet governeth it self in its particular revolution, and
how precisely the structure of its Orb is framed; which is that
which is vulgarly called the Theory of the Planets, we cannot as
yet undoubtedly resolve. Mars, that hath so much puzled our
Modern Astronomers, is a proof of this: And to the Moon her
self there have been assigned several Theories, after that the said
Copernicus had much altered it from that of Ptolomy. And to
descend to our particular case, that is to say, to the apparent mo
tion of the Sun and Moon; touching the former, there hath been
observed a certain great irregularity, whereby it passeth the two

semicircles of the Ecliptick, divided by the points of the Equi
noxes in very different times; in passing one of which, it spend
eth about nine dayes more than in passing the other; a difference,
as you see, very great and notable. But if in passing small arches,
such for example as are the twelve Signs, he maintain a most re
gular motion, or else proceed with paces, one while a little more
swift, and another more slow, as it is necessary that it do, in case
the annual motion belong to the Sun onely in appearance, but
in reality to the Earth in company with the Moon, it is what hath
not hitherto been observed, nor it may be, sought. Touching

the Moon in the next place, whose restitutions have been prin
cipally lookt into an account of the Eclipses, for which it is suf
ficient to have an exact knowledge of its motion about the Earth,