Archimedes Texts

169
then when they are in a state of having a propension of moving
naturally to the same. Tie a bottle that hath water in it, to
the end of a cord, and holding the other end fast in your hand,
and making the cord and your arm the semi-diameter, and the
knitting of the shoulder the centre, swing the bottle very fast a
bout, so as that it may describe the circumference of a circle,
which, whether it be parallel to the Horizon, or perpendicular to
it, or any way inclined, it shall in all cases follow, that the wa
ter will not fall out of the bottle: nay, he that shall swing it,
shall find the cord always draw, and strive to go farther from the
shoulder. And if you bore a hole in the bottom of the bottle,
you shall see the water spout forth no less upwards into the skie,
than laterally, and downwards to the Earth; and if instead of wa
ter, you shall put little pebble stones into the bottle, and swing it
in the same manner, you shall find that they will strive in the like
manner against the cord. And lastly, we see boys throw stones
a great way, by swinging round a piece of a stick, at the end of
which the stone is let into a slit (which stick is called by them a
sling;) all which are arguments of the truth of the conclusion,
to wit, that the vertigo or swing conferreth upon the moveable,
a motion towards the circumference, in case the motion be swift:
and therefore if the Earth revolve about its own centre, the mo
tion of the superficies, and especially towards the great circle,
as being incomparably more swift than those before named, ought
to extrude all things up into the air.

SIMP. The Argument seemeth to me very well proved and
inforced; and I believe it would be an hard matter to answer and
overthrow it.

SALV. Its solution dependeth upon certain notions no less
known and believed by you, than by my self: but because they
come not into your mind, therefore it is that you perceive not the
answer; wherefore, without telling you it (for that you know the
same already) I shall with onely assisting your memory, make you
to refute this argument.

SIMP. I have often thought of your way of arguing, which
hath made me almost think that you lean to that opinion of Pla-

to, Quòd nostrum scire sit quoddam reminisci; therefore I intreat
you to free me from this doubt, by letting me know your judg
ment.

SALV. What I think of the opinion of Plato, you may gather
from my words and actions. I have already in the precedent con
ferences expresly declared my self more than once; I will pursue
the same style in the present case, which may hereafter serve you
for an example, thereby the more easily to gather what my opi
nion is touching the attainment of knowledg, when a time shall