Galilei, Galileo, The systems of the world, 1661

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1the Axis of the grand Orb, the Earths centre being in the
tial
point of Capricorn.
Suppoſing therefore the Terreſtrial
Globe
to have its centre in the point Capricorn, we will deſcribe
its
Poles and Axis A B, inclined upon the diameter Capricorn
Cancer
23 degrees and an half; ſo that the angle A Capricorn
Cancer
cometh to be the complement of a Quadrant or Radius,
that
is, 66 degrees and an half; and this inclination muſt be
derſtood
to be immutable, and we will ſuppoſe the ſuperiour
Pole
A to be Boreal, or North, and the other Auſtral, or South.
Now imagining the Earth to revolve in it ſelf about the Axis A B
in
twenty four hours, from Weſt to Eaſt, there ſhall by all the
points
aſſigned in its ſuperſicies, be circles deſcribed parallel to
each
other.
We will draw, in this firſt poſition of the Earth,
the
greateſt C D, and thoſe two diſtant from it gr. 23. and an
half
, E F above, and G M beneath, and the other two extream
ones
I K and L M remote, by thoſe intervals from the Poles A
and
B; and as we have marked theſe five, ſo we may imagine
numerable
others, parallel to theſe, deſcribed by the
ble
points of the Terreſtrial ſurface.
Next let us ſuppoſe the
Earth
, with the annual motion of its centre, to transferre it ſelf
into
the other places already marked; but to paſſe thither in ſuch
a
manner, that its own Axis A B ſhall not only not change
nation
upon the plain of the Ecliptick, but ſhall alſo never vary
direction
; ſo that alwayes keeping parallel to it ſelf, it may
continually
tend towards the ſame part of the Univerſe, or, if
you
will, of the Firmament, whereas, if we do but ſuppoſe it
prolonged
, it will, with its extream termes, deſigne a Circle
rallel
and equal to the grand Orb, Libra Capricorn Aries Cancer,
as
the ſuperiour baſe of a Cylinder deſcribed by it ſelf in the
nual
motion above the inferiour baſe, Libra Capricorn Aries
Cancer
.
And therefore this immutability of inclination
nuing
, we will deſign theſe other three figures about the centres
Aries
, Cancer, and Libra, alike in every thing to that firſt
ſcribed
about the centre Capricorn.
Now we will conſider the
firſt
figure of the Earth, in which, in regard the Axis A B is
clined
from perpendicularity upon the diameter Capricorn
cer
23 degrees and an half towards the Sun O, and the arch A I
being
alſo 23 degrees and an half, the illumination of the Sun
will
illuſtrate the Hemiſphere of the Terreſtrial Globe expoſed
towards
the Sun (of which, in this place, half is to be ſeen)
vided
from the obſcure part by the Terminator of the light
I
M, by which the parallel C D, as being a grand circle, ſhall
come
to be divided into equal parts, but all the reſt into parts
equal
; being that the terminator of the light I M paſſeth not
by
their Poles A B, and the parallel I K, together with all the reſt

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