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

Page concordance

< >
Scan Original
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
< >
page |< < of 77 > >|
1tion is not inferiour; whereupon, we muſt of neceſſity conclude
that
it is nothing: becanſe, if it were of any ſenſible power, ſome
large
Plate might be found or compounded of a Matter alike in
vity
to the water, which not only would ſtay between the two
ters
; but, moreover, ſhould not be able to deſcend or aſcend
out
notable force.
We may likewiſe collect the ſame from an

ther
Experiment, ſhewing that the Water gives way alſo in the ſame
manner
to tranſverſall Diviſion; for if in a ſetled and ſtanding water
we
ſhould place any great Maſs that goeth not to the bottom,
ing
it with a ſingle (Womans) Hair, we might carry it from place to
place
without any oppoſition, and this whatever Figure it hath,
though
that it poſſeſs a great ſpace of water, as for inſtance, a great
Beam
would do moved ſide-ways.
Perhaps ſome might oppoſe me
and
ſay, that if the Reſiſtance of water againſt Diviſion, as I affirm,
were
nothing; Ships ſhould not need ſuch a force of Oars and Sayles
for
the moving of them from place to place in a tranquile Sea, or
ſtanding
Lake.
To him that ſhould make ſuch an objection, I would

reply
, that the water contraſteth not againſt, nor ſimply reſiſteth
Diviſion
, but a ſudden Diviſion, and with ſo much greater
tence
, by how much greater the Velocity is: and the Cauſe of this
Reſiſtance
depends not on Craſſitude, or any other thing that
lutely
oppoſeth Diviſion, but becauſe that the parts of the water
divided
, in giving way to that Solid that is moved in it, are
ſelves
alſo neceſſitated locally to move, ſome to the one ſide, and ſome
to
the other, and ſome downwards: and this muſt no leſs be done
by
the waves before the Ship, or other Body ſwimming through the
water
, than by the poſteriour and ſubſequent; becauſe, the Ship
proceeding
forwards, to make it ſelf a way to receive its Bulk, it is
requiſite
, that with the Prow it repulſe the adjacent parts of the
water
, as well on one hand as on the other, and that it move them
as
much tranſverſly, as is the half of the breadth of the Hull: and
the
like removall muſt thoſe waves make, 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
vancing
forwards, goeth, leaving vacant.
Now, becauſe, all

tions
are made in Time, 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.

Text layer

  • Dictionary
  • Places

Text normalization

  • Original
  • Regularized
  • Normalized

Search


  • Exact
  • All forms
  • Fulltext index
  • Morphological index