Galilei, Galileo - Discourse concerning the natation of bodies

Galilei, Galileo, Discourse concerning the natation of bodies, 1663

None
Concordance
Figures
Thumbnails

List of thumbnails

11	12
13	14
15	16
17	18
19	20

Solid that weighs above 100 pounds: in that we have demonſtra
ted, That it ſufficeth, that ſuch difference be found between the
Specificall Gravities of the Mediums and Moveables, let the particular
and abſolute Gravities be what they will: inſomuch, that a Solid,
provided that it be Specifically leſs grave than the water, although
its abſolute weight were 1000 pounds, yet may it be born up and
elevated by ten pounds of water, and leſs: and on the contrary, a
nother Solid, ſo that it be Specifically more grave than the water,
though in abſolute Gravity it were not above a pound, yet all the
water in the Sea, cannot raiſe it from the Bottom, or float it. This
ſufficeth me, for my preſent occaſion, to have, by the above declared
Examples, diſcovered and demonſtrated, without extending ſuch
matters farther, and, as I might have done, into a long Treatiſe:
yea, but that there was a neceſſity of reſolving the above propoſed
doubt, I ſhould have contented my ſelf with that only, which is
demonſtrated by Archimedes, in his firſt Book De Inſidentibus hu
mido: where in generall termes he infers and confirms the ſame

Concluſions, namely, that Solids (a) leſs grave than water, ſwim or

float upon it, the (b) more grave go to the Bottom, and the (c) e

qually grave reſt indifferently in all places, yea, though they ſhould
be wholly under water.

(a) Lib. 1. Prop. 4.

(b) Id. Lib. 1.
Prop. 3.

(c) Id. Lib. 1.
Prop. 3.

But, becauſe that this Doctrine of Archimedes, peruſed, tranſcri

bed and examined by Signor Franceſco Buonamico, in his fifth Book
of Motion, Chap. 29, and afterwards by him confuted, might by the
Authority of ſo renowned, and famous a Philoſopher, be rendered
dubious, and ſuſpected of falſity; I have judged it neceſſary to de
fend it, if I am able ſo to do, and to clear Archimedes, from thoſe
cenſures, with which he appeareth to be charged. Buonamico re

jecteth the Doctrine of Archimedes, firſt, as not conſentaneous with
the Opinion of Aristotle, adding, that it was a ſtrange thing to him,

that the Water ſhould exceed the Earth in Gravity, ſeeing on the
contrary, that the Gravity of water, increaſeth, by means of the parti

cipation of Earth. And he ſubjoyns preſently after, that he was
not ſatisfied with the Reaſons of Archimedes, as not being able with
that Doctrine, to aſſign the cauſe whence it comes, that a Boat and
a Veſſell, which otherwiſe, floats above the water, doth ſink to the
Bottom, if once it be filled with water; that by reaſon of the e
quality of Gravity, between the water within it, and the other water
without, it ſhould ſtay a top; but yet, nevertheleſs, we ſee it to go to
the Bottom.

The Authors
defence of Ar
chimedes his Do
ctrine, againſt
the oppoſitions
of Buonamico.

His firſt Objecti
on againſt the
Doctrine of Ar
chimedes.

His Second Ob
jection.

His third Obje
ction.

His ſourth Ob
jection.

He farther addes, that Ariſtotle had clearly confuted the Ancients,
who ſaid, that light Bodies moved upwards, driven by the impulſe

of the more grave Ambient: which if it were ſo, it ſhould ſeem of
neceſſity to follow, that all naturall Bodies are by nature heavy,

Text layer

Text normalization

Search