A Discourse Presented to the Most Serene Don Cosimo II., Great Duke of Tuscany, Concerning the Natation of Bodies Vpon, and Submersion In, the Water.Galilei, Galileo
Science
A Discourse Presented to the Most Serene Don Cosimo II., Great Duke of Tuscany, Concerning the Natation of Bodies Vpon, and Submersion In, the Water.
Galilei, Galileo
Hydrostatics; Specific gravity
that succeeding the Poump do run from the remoter parts of the Ship
towards those of the middle, successively to replenish the places,
which the Ship in advancing forwards, goeth, leaving vacant. Now,
because, all Motitions are made in Time[62], and the longer in greater
time: and it being moreover true, that those Bodies that in a certain
time are moved by a certain power such a certain space, shall not be
moved the same space, and in a shorter Time, unless by a greater
Power: therefore, the broader Ships move slower than the narrower,
being put on by an equall Force: and the same Vessel requires so much
greater force of Wind, or Oars, the faster it is to move.
[60] An hair will draw a great Mass thorow the Water; which
proveth, that it hath no Resistance against transversall
Division.
[61] How ships are moved in the water.
[62] Bodies moved a certain space in a certain Time, by a
certain power, cannot be moved the same space and in a shorter
time, but by a greater power.
_But yet for all this, any great Mass swimming in a standing Lake,
may be moved by any petit force; only it is true, that a lesser
force more slowly moves it: but if the waters Resistance of
Division, were in any manner sensible, it would follow, that the
said Mass, should, notwithstanding the percussion of some sensible
force, continue immoveable, which is not so[63]. Yea, I will say
farther, that should we retire our selves into the more internall
contemplation of the Nature of water and other Fluids, perhaps we
should discover the Constitution of their parts to be such, that
they not only do not oppose Division, but that they have not any
thing in them to be divided: so that the Resistance that is
observed in moving through the water[64], is like to that which we meet
with in passing through a great Throng of People, wherein we find
impediment, and not by any difficulty in the Division, for that
none of those persons are divided whereof the Croud is composed,
but only in moving of those persons side-ways which were before
divided and disjoyned: and thus we find Resistance in thrusting a
Stick into an heap of Sand, not because any part of the Sand is to
be cut in pieces, but only to be moved and raised[65]. Two manners of
Penetration, therefore, offer themselves to us, one in Bodies,
whose parts were continuall, and here Division seemeth necessary,
the other in the aggregates of parts not continuall, but contiguous
only[66], and here there is no necessity of dividing but of moving
only. Now, I am not well resolved, whether water and other Fluids
may be esteemed to be of parts continuall or contiguous only[67]; yet I
find my self indeed inclined to think that they are rather
contiguous (if there be in Nature no other manner of aggregating,
than by the union, or by the touching of the extreams:) and I am
induced thereto by the great difference that I see between the
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account