Galilei, Galileo
,
Discourse concerning the natation of bodies
,
1663
Text
Text Image
XML
Document information
None
Concordance
Figures
Thumbnails
page
|<
<
of 77
>
>|
<
archimedes
>
<
text
>
<
body
>
<
chap
>
<
p
type
="
main
">
<
s
>
<
pb
pagenum
="
441
"/>
tion is not inferiour; whereupon, we muſt of neceſſity conclude
<
lb
/>
that it is nothing: becanſe, if it were of any ſenſible power, ſome
<
lb
/>
large Plate might be found or compounded of a Matter alike in
<
lb
/>
vity to the water, which not only would ſtay between the two
<
lb
/>
ters; but, moreover, ſhould not be able to deſcend or aſcend
<
lb
/>
out notable force. </
s
>
<
s
>We may likewiſe collect the ſame from an
<
lb
/>
<
arrow.to.target
n
="
marg1491
"/>
<
lb
/>
ther Experiment, ſhewing that the Water gives way alſo in the ſame
<
lb
/>
manner to tranſverſall Diviſion; for if in a ſetled and ſtanding water
<
lb
/>
we ſhould place any great Maſs that goeth not to the bottom,
<
lb
/>
ing it with a ſingle (Womans) Hair, we might carry it from place to
<
lb
/>
place without any oppoſition, and this whatever Figure it hath,
<
lb
/>
though that it poſſeſs a great ſpace of water, as for inſtance, a great
<
lb
/>
Beam would do moved ſide-ways. </
s
>
<
s
>Perhaps ſome might oppoſe me
<
lb
/>
and ſay, that if the Reſiſtance of water againſt Diviſion, as I affirm,
<
lb
/>
were nothing; Ships ſhould not need ſuch a force of Oars and Sayles
<
lb
/>
for the moving of them from place to place in a tranquile Sea, or
<
lb
/>
ſtanding Lake. </
s
>
<
s
>To him that ſhould make ſuch an objection, I would
<
lb
/>
<
arrow.to.target
n
="
marg1492
"/>
<
lb
/>
reply, that the water contraſteth not againſt, nor ſimply reſiſteth
<
lb
/>
Diviſion, but a ſudden Diviſion, and with ſo much greater
<
lb
/>
tence, by how much greater the Velocity is: and the Cauſe of this
<
lb
/>
Reſiſtance depends not on Craſſitude, or any other thing that
<
lb
/>
lutely oppoſeth Diviſion, but becauſe that the parts of the water
<
lb
/>
divided, in giving way to that Solid that is moved in it, are
<
lb
/>
ſelves alſo neceſſitated locally to move, ſome to the one ſide, and ſome
<
lb
/>
to the other, and ſome downwards: and this muſt no leſs be done
<
lb
/>
by the waves before the Ship, or other Body ſwimming through the
<
lb
/>
water, than by the poſteriour and ſubſequent; becauſe, the Ship
<
lb
/>
proceeding forwards, to make it ſelf a way to receive its Bulk, it is
<
lb
/>
requiſite, that with the Prow it repulſe the adjacent parts of the
<
lb
/>
water, as well on one hand as on the other, and that it move them
<
lb
/>
as much tranſverſly, as is the half of the breadth of the Hull: and
<
lb
/>
the like removall muſt thoſe waves make, that ſucceeding the Poump
<
lb
/>
do run from the remoter parts of the Ship towards thoſe of the
<
lb
/>
middle, ſucceſſively to repleniſh the places, which the Ship in
<
lb
/>
vancing forwards, goeth, leaving vacant. </
s
>
<
s
>Now, becauſe, all
<
lb
/>
<
arrow.to.target
n
="
marg1493
"/>
<
lb
/>
tions are made in Time, and the longer in greater time: and it being
<
lb
/>
moreover true, that thoſe Bodies that in a certain time are moved
<
lb
/>
by a certain power ſuch a certain ſpace, ſhall not be moved the ſame
<
lb
/>
ſpace, and in a ſhorter Time, unleſs by a greater Power: therefore,
<
lb
/>
the broader Ships move ſlower than the narrower, being put on by
<
lb
/>
an equall Force: and the ſame Veſſel requires ſo much greater
<
lb
/>
force of Wind, or Oars, the faſter it is to move.</
s
>
</
p
>
</
chap
>
</
body
>
</
text
>
</
archimedes
>