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

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1velocity, no imaginable diverſity could be found either in this,
or any other experiment whatſoever, as I am anon to tell you.
Now if in this caſe there appeareth no difference at all, what can
be pretended to be ſeen in the ſtone falling from the top of the
Tower, where the motion in gyration is not adventitious, and
cidental, but natural and eternal; and where the air exactly
loweth the motion of the Tower, and the Tower that of the
reſtrial Globe?
have you any thing elſe to ſay, Simplicius, upon
this particular?
SIMP. No more but this, that I ſee not the mobility of the
Earth as yet proved.
SALV. Nor have I any intention at this time, but onely to
ſhew, that nothing can be concluded from the experiments
ed by our adverſaries for convincing Arguments: as I think I
ſhall prove the others to be.
SAGR. I beſeech you, Salviatus, before you proceed any
ther, to permit me to ſtart certain queſtions, which have been
rouling in my fancy all the while that you with ſo much patience
and equanimity, was minutely explaining to Simplicius the
riment of the Ship.
SALV. We are here met with a purpoſe to diſpute, and it's fit
that every one ſhould move the difficulties that he meets withall,
for this is the way to come to the knowledg of the truth.
Therefore ſpeak freely.
SAGR. If it be true, that the impetus wherewith the ſhip moves,
doth remain indelibly impreſſ'd in the ſtone, after it is let fall from
the Maſt; and if it be farther true, that this motion brings no
pediment or retardment to the motion directly downwards,
tural to the ſtone: it's neceſſary, that there do an effect enſue of

a very wonderful nature.
Let a Ship be ſuppoſed to ſtand ſtill,
and let the time of the falling of a ſtone from the Maſts Round-top
to the ground, be two beats of the pulſe; let the Ship afterwards
be under ſail, and let the ſame ſtone depart from the ſame place,
and it, according to what hath been premiſed, ſhall ſtill take up
the time of two pulſes in its fall, in which time the ſhip will have
run, ſuppoſe, twenty yards; To that the true motion of the ſtone
will be a tranſverſe line, conſiderably longer than the firſt ſtraight
and perpendicular line, which is the length of the ^{*} Maſt, and yet

nevertheleſs the ^{*} ſtone will have paſt it in the ſame time.
Let
it be farther ſuppoſed, that the Ships motion is much more
rated, ſo that the ſtone in falling ſhall be to paſs a tranſverſe line
much longer than the other; and in ſum, increaſing the Ships

locity as much as you will, the falling ſtone ſhall deſcribe its
verſe lines ſtill longer and longer, and yet ſhall paſs them all in
thoſe ſelf ſame two pulſes.
And in this faſhion, if a Canon were