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

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1level'd on the top of a Tower, and ſhots were made therewith
point blank, that is, paralel to the Horizon, let the Piece have a
greater or leſs charge, ſo as that the ball may fall ſometimes a
thouſand yards diſtant, ſometimes four thouſand, ſometimes ſix,
ſometimes ten, &c. and all theſe ſhots ſhall curry or finiſh their
ranges in times equal to each other, and every one equal to the
time which the ball would take to paſs from the mouth of the
Piece to the ground, being left, without other impulſe, to fall
ſimply downwards in a perpendicular line.
Now it ſeems a very
admirable thing, that in the ſame ſhort time of its falling
dicularly down to the ground, from the height of, ſuppoſe, an
hundred yards, the ſame ball, being thruſt violently out of the
Piece by the Fire, ſhould be able to paſs one while four hundred,
another while a thouſand, another while four, another while ten
thouſand yards, ſo as that the ſaid ball in all ſhots made point
blank, always continueth an equal time in the air.
accident in the
tion of projects.
*By the length of
the maſt he means
the diſtance
tween the
deck and
top.
* La palla.
SALV. The conſideration for its novelty is very pretty, and if
the effect be true, very admirable: and of the truth thereof, I
make no queſtion: and were it not for the accidental impediment
of the air, I verily believe, that, if at the time of the balls going
out of the Piece, another were let fall from the ſame height
rectly downwards, they would both come to the ground at the
ſame inſtant, though that ſhould have curried ten thouſand
miles in its range, and this but an hundred onely: preſuppoſing
the ſurface of the Earth to be equal, which to be aſſured of, the
experiment may be made upon ſome lake.
As for the impediment
which might come from the air, it would conſiſt in retarding the
extreme ſwift motion of the ſhot.
Now, if you think fit, we will
proceed to the ſolution of the other Objections, ſeeing that
plicius (as far as I can ſee) is convinc'd of the nullity of this firſt,
taken from things falling from on high downwards.
SIMP. I find not all my ſcruples removed, but it may be the
fault is my own, as not being of ſo eaſie and quick an apprehenſion
as Sagredus. And it ſeems to me, that if this motion, of which
the ſtone did partake whilſt it was on the Round-top of the Ships
Maſt, be, as you ſay, to conſerve it ſelf indelibly in the ſaid ſtone,
even after it is ſeparated from the Ship, it would follow, that
wiſe in caſe any one, riding a horſe that was upon his ſpeed, ſhould
let a bowl drop out of his hand, that bowl being fallen to the
ground would continue its motion and follow the horſes ſteps,
without tarrying behind him: the which effect, I believe, is not
to be ſeen, unleſs when he that is upon the horſe ſhould throw it
with violence that way towards which he runneth; but otherwiſe,
I believe it will ſtay on the ground in the ſame place where it
fell.