Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667
page |< < of 701 > >|
1calm and tranquill. And if I had continually held that pen in
my hand, and had onely moved it ſometimes an inch or two this
way or that way, what alteration ſhould I have made in that its
principal, and very long tract or ſtroke?
SIMP. Leſs than that which the declining in ſeveral places from
abſolute rectitude, but the quantity of a flea's eye makes in a right
line of a thouſand yards long.
SAGR. If a Painter, then, at our launching from the Port, had
began to deſign upon a paper with that pen, and continued his
work till he came to Scanderon, he would have been able to have
taken by its motion a perfect draught of all thoſe figures perfectly
interwoven and ſhadowed on ſeveral ſides with countreys,
ings, living creatures, and other things; albeit all the true, real,
and eſſential motion traced out by the neb of that pen, would
have been no other than a very long, but ſimple line: and as to
the proper operation of the Painter, he would have delineated the
ſame to an hair, if the ſhip had ſtood ſtill.
That therefore of the
huge long motion of the pen there doth remain no other marks,
than thoſe tracks drawn upon the paper, the reaſon thereof is
cauſe the grand motion from Venice to Scanderon, was common to
the paper, the pen, and all that which was in the ſhip: but the petty
motions forwards and backwards, to the right, to the left,
municated by the fingers of the Painter unto the pen, and not to
the paper, as being peculiar thereunto, might leave marks of it ſelf
upon the paper, which did not move with that motion.
Thus it
is likewiſe true, that the Earth moving, the motion of the ſtone in
deſcending downwards, was really a long tract of many hundreds
and thouſands of yards, and if it could have been able to have
lineated in a calm air, or other ſuperficies, the track of its courſe,
it would have left behind an huge long tranſverſe line.
But that
part of all this motion which is common to the ſtone, the Tower,
and our ſelves, is imperceptible to us, and as if it had never been,
and that part onely remaineth obſervable, of which neither the
Tower nor we are partakers, which is in fine, that wherewith the
ſtone falling meaſureth the Tower.
SALV. A moſt witty conceipt to clear up this point, which was
not a little difficult to many capacities.
Now if Simplicius will
make no farther reply, we may paſs to the other experiments, the
unfolding of which will receive no ſmall facility from the things