Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667

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1circular which we preſuppoſe natural to the whole Terreſtrial
Globe, of which the ſtone is a part.
Ariſtotle
teth that the Fire
moveth directly
upwards by
ture, and round
bout by
tion.
SIMPL. I ſee no ſuch thing: for if the element of Fire
volve round together with the Air, it is a very eaſie, yea a neceſſary
thing, that a ſpark of fire which from the Earth mounts upwards,
in paſſing thorow the moving air, ſhould receive the ſame motion,
being a body ſo thin, light, and eaſie to be moved: but that a
very heavy ſtone, or a Canon bullet, that deſcendeth from on
high, and that is at liberty to move whither it will, ſhould ſuffer
it ſelf to be tranſported either by the air or any other thing, is
altogether incredible.
Beſides that, we have the Experiment,
which is ſo proper to our purpoſe, of the ſtone let fall from the
round top of the Maſt of a ſhip, which when the ſhip lyeth ſtill,
falleth at the Partners of the Maſt; but when the ſhip ſaileth, falls
ſo far diſtant from that place, by how far the ſhip in the time of
the ſtones falling had run forward; which will not be a few
thoms, when the ſhips courſe is ſwift.
SALV. There is a great diſparity between the caſe of the Ship

and that of the Earth, if the Terreſtrial Globe be ſuppoſed to have
a diurnal motion.
For it is a thing very manifeſt, that the
tion of the Ship, as it is not natural to it, ſo the motion of all thoſe
things that are in it is accidental, whence it is no wonder that the
ſtone which was retained in the round top, being left at liberty,
deſcendeth downwards without any obligation to follow the
tion of the Ship.
But the diurnal converſion is aſcribed to the
Terreſtrial Globe for its proper and natural motion, and
quently, it is ſo to all the parts of the ſaid Globe; and, as being
impreſs'd by nature, is indelible in them; and therefore that ſtone
that is on the top of the Tower hath an intrinſick inclination of
revolving about the Centre of its Whole in twenty four hours, and
this ſame natural inſtinct it exerciſeth eternally, be it placed in any
ſtate whatſoever.
And to be aſſured of the truth of this, you
have no more to do but to alter an antiquated impreſſion made
in your mind; and to ſay, Like as in that I hitherto holding it to
be the property of the Terreſtrial Globe to reſt immoveable about
its Centre, did never doubt or queſtion but that all whatſoever
particles thereof do alſo naturally remain in the ſame ſtate of reſt:
So it is reaſon, in caſe the Terreſtrial Globe did move round by
natural inſtinct in twenty four hours, that the intrinſick and
ral inclination of all its parts ſhould alſo be, not to ſtand ſtill, but