rne by several motions besides the first. The Earth must also be borne
on by two sorts of motion, whether it be situate around a mid-point, or in
the middle site of the universe: and if this were so, there must needs be
at one time an advance, at another time a retrogression of the fixed stars:
This, however, does not seem to be the case, but they rise and set always
the same in the same places." But it by no means follows that a double
motion must be assigned to the Earth. But if there be but one diurnal
motion of the Earth around its poles, who does not see that the stars must
always in the same manner rise and set at the same points of the horizon,
even although there be another motion about which we are not disputing:
since the mutations in the smaller orbit cause no variation of aspect in
the fixed stars owing to their great distance, unless the axis of the Earth
have varied its position, concerning which we raise a question when
speaking of the cause of the praecession of the aequinoxes. In this
argument are many flaws. For if the Earth revolve, that we asserted must
needs occur not by reason of the first sphaere, but of its innate forces.
But if it were set in motion by the first sphaere, there would be no
successions of days and nights, for it would continue its course along with
the _Primum Mobile_. But that the Earth is affected by a double movement at
the time when it rotates around its own centre, because the rest of the
stars move with a double motion, does not follow. Besides, he does not well
consider the argument, nor do his interpreters understand the same. [Greek:
toutou de sumbainontos, anankaion gignesthai parodous kai tropas ton
endedemenon astron.] (Arist. _de Coelo_, ii. chap. 14.) That is, "If this
be so, there must needs be changes, and retrogressions of the fixed stars."
What some interpret as retrogressions or regressions, and changes of the
fixed stars, others explain as diversions: which terms can in no way be
understood of axial motion, unless he meant that the Earth moved by the
_Primum Mobile_ is borne and turned over other poles diverse even from
those which correspond to the first sphaere, which is altogether absurd.
Other later theorists suppose that the eastern ocean ought to be impelled
so into western regions by that motion, that those parts of the Earth which
are dry and free from water would be daily flooded by the eastern ocean.
But the ocean is not acted upon by that movement, since