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

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1the courſe of the wind, and the other ſidelong, the wind will
quickly carry away this later, and leave the other where it was;
and the ſame to my ſeeming, ought to happen, if the Doctrine of
Ariſtotle were true, of thoſe two ſhot out of a Bow: foraſmuch
as the arrow ſhot ſideways is driven by a great quantity of Air,
moved by the bowſtring, to wit by as much as the ſaid ſtring is
long, whereas the other arrow receiveth no greater a quantity of
air, than the ſmall circle of the ſtrings thickneſs.
And I cannot
imagine what may be the reaſon of ſuch a difference, but would
fain know the ſame.
SIMP. The cauſe ſeemeth to me ſufficiently manifeſt; and it
is, becauſe the arrow ſhot endways, hath but a little quantity of
air to penetrate, and the other is to make its way through a
tity as great as its whole length.
SALV. Then it ſeems the arrows ſhot, are to penetrate the air?
but if the air goeth along with them, yea, is that which carrieth
them, what penetration can they make therein?
Do you not ſee
that, in this caſe, the arrow would of neceſſity move with greater
velocity than the air?
and this greater velocity, what doth confer
it on the arrow?
Will you ſay the air giveth them a velocity
greater than its own?
Know then, Simplicius, that the buſineſs
proceeds quite contrary to that which Ariſtotle ſaith, and that the

medium conferreth the motion on the project, is as falſe, as it is
true, that it is the onely thing which procureth its obſtruction; and
having known this, you ſhall underſtand without finding any thing
whereof to make queſtion, that if the air be really moved, it doth
much better carry the dart along with it longways, than endways,
for that the air which impelleth it in that poſture, is much, and in
this very little.
But ſhooting with the Bow, foraſmuch as the air
ſtands ſtill, the tranſverſe arrow, being to force its paſſage through
much air, comes to be much impeded, and the other that was nock't
eaſily overcometh the obſtruction of the ſmall quantity of air,
which oppoſeth it ſelf thereto.
The medium doth
impede and not
fer the motion of
projects.
SALV. How many Propoſitions have I obſerved in Ariſtotle,
(meaning ſtill in Natural Philoſophy) that are not onely falſe,
but falſe in ſuch ſort, that its diametrical contrary is true, as it
happens in this caſe.
But purſuing the point in hand, I think that
Simplicius is perſwaded, that, from ſeeing the ſtone always to fall
in the ſame place, he cannot conjecture either the motion or
bility of the Ship: and if what hath been hitherto ſpoken,
ſhould not ſuffice, there is the Experiment of the medium which
may thorowly aſſure us thereof; in which experiment, the moſt
that could be ſeen would be, that the cadent moveable might be
left behind, if it were light, and that the air did not follow the
motion of the ſhip: but in caſe the air ſhould move with equal