Galilei, Galileo - Discourse concerning the natation of bodies

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

None
Concordance
Figures
Thumbnails

Page concordance

Scan	Original
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

namely, that Earth is leſs Grave than Water. The Veſſel that ſwims
occupieth in the water, not only a place equall to the Maſs of the
Earth, of which it is formed; but equall to the Earth and to the Air
together, contained in its concavity. And, if ſuch a Maſs compoun
ded of Earth and Air, ſhall be leſs grave than ſuch another quantity
of water, it ſhall ſwim, and ſhall accord with the Doctrine of Archi
medes; but if, again, removing the Air, the Veſſell ſhall be filled
with water, ſo that the Solid put in the water, be nothing but
Earth, nor occupieth other place, than that which is only poſſeſt by
Earth, it ſhall then go to the Bottom, by reaſon that the Earth is
heavier than the water: and this correſponds well with the meaning
of Archimedes. See the ſame effect illuſtrated, with ſuch another
Experiment, In preſſing a Viall Glaſs to the Bottom of the water,
when it is full of Air, it will meet with great reſiſtance, becauſe it is
not the Glaſs alone, that is preſſed under water, but together with
the Glaſs a great Maſs of Air, and ſuch, that if you ſhould take as
much water, as the Maſs of the Glaſs, and of the Air contained in it,
you would have a weight much greater than that of the Viall, and of
its Air: and, therefore, it will not ſubmerge without great violence:
but if we demit only the Glaſs into the water, which ſhall be when
you ſhall fill the Glaſs with water, then ſhall the Glaſs deſcend to
the Bottom; as ſuperiour in Gravity to the water.

The Authors an
ſwer to the firſt
Objection.

The Authors an
ſwer to the ſe
cond Objection.

Returning, therefore, to our firſt purpoſe; I ſay, that Earth is
more grave than water, and that therefore, a Solid of Earth goeth to
the bottom of it; but one may poſſibly make a compoſition of Earth
and Air, which ſhall be leſs grave than a like Maſs of Water; and
this ſhall ſwim: and yet both this and the other experiment ſhall
very well accord with the Doctrine of Archimedes. But becauſe that
in my judgment it hath nothing of difficulty in it, I will not poſitive
ly affirme that Signor Buonamico, would by ſuch a diſcourſe object
unto Archimedes the abſurdity of inferring by his doctrine, that Earth
was leſs grave than Water, though I know not how to conceive what
other accident he could have induced thence.

Perhaps ſuch a Probleme (in my judgement falſe) was read by
Signor Buonamico in ſome other Author, by whom peradventure it
was attributed as a ſingular propertie, of ſome particular Water, and
ſo comes now to be uſed with a double errour in confutation of Ar
chimedes, ſince he ſaith no ſuch thing, nor by him that did ſay it was it
meant of the common Element of Water.

The third difficulty in the doctrine of Archimedes was, that he

could not render a reaſon whence it aroſe, that a piece of Wood,
and a Veſſell of Wood, which otherwiſe floats, goeth to the bottom,
if filled with Water. Signor Buonamico hath ſuppoſed that a Verſſell
of Wood, and of Wood that by nature ſwims, as before is ſaid,

Text layer

Text normalization

Search