Salusbury, Thomas
,
Mathematical collections and translations (Tome I)
,
1667
Text
Text Image
Image
XML
Thumbnail overview
Document information
None
Concordance
Figures
Thumbnails
page
|<
<
of 701
>
>|
<
archimedes
>
<
text
>
<
body
>
<
chap
>
<
p
type
="
main
">
<
s
>
<
pb
xlink:href
="
040/01/1009.jpg
"
pagenum
="
315
"/>
alſo inſtead of the Chord that rolleth about the Cylinder C, place
<
lb
/>
there a ſmall Wheel with teeth or Coggs, that may turn another
<
lb
/>
greater, and by that means multiply the power of the Force as
<
lb
/>
much as one ſhall pleaſe, without having any thing to deduct of
<
lb
/>
the ſame, ſave only the difficulty of moving the Machine, as in the
<
lb
/>
others.</
s
>
</
p
>
<
p
type
="
head
">
<
s
>
<
emph
type
="
italics
"/>
The
<
emph.end
type
="
italics
"/>
SCREW,
<
emph
type
="
italics
"/>
Cochlea.
<
emph.end
type
="
italics
"/>
</
s
>
</
p
>
<
p
type
="
main
">
<
s
>When once the Force of the Capſten and of the In
<
lb
/>
clined Plane is underſtood, that of the Screw is eaſie
<
lb
/>
to be computed, for it is compoſed only of a Plane
<
lb
/>
much inclined, which windeth about a Cylinder: and if this Plane
<
lb
/>
be in ſuch manner Inclined, as that the Cylinder ought to make
<
lb
/>
<
emph
type
="
italics
"/>
v. </
s
>
<
s
>gr.
<
emph.end
type
="
italics
"/>
ten turns to advance forwards the length of a foot in the
<
lb
/>
Screw, and that the bigneſs of the Circumference of the Circle
<
lb
/>
<
figure
id
="
id.040.01.1009.1.jpg
"
xlink:href
="
040/01/1009/1.jpg
"
number
="
213
"/>
<
lb
/>
which the Force that turneth it
<
lb
/>
about doth deſcribe be of ten
<
lb
/>
feet; foraſmuch as ten times ten
<
lb
/>
are one hundred, one Man alone
<
lb
/>
ſhall be able to preſs as ſtrongly
<
lb
/>
with this Inſtrument, or Screw, as
<
lb
/>
one hundred without it, provided
<
lb
/>
alwaies, that we rebate the Force
<
lb
/>
that is required to the turning
<
lb
/>
of it.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>Now I ſpeak here of Preſſing rather than of Raiſing, or Remo
<
lb
/>
ving, in regard that it is about this moſt commonly that the Screw
<
lb
/>
is employed, but when we would make uſe of it for the raiſing of
<
lb
/>
Weights, inſtead of making it to advance into a Female Screw, we
<
lb
/>
joyn or apply unto it a Wheel of many Coggs, in ſuch ſort
<
lb
/>
made, that if
<
emph
type
="
italics
"/>
v. </
s
>
<
s
>gr.
<
emph.end
type
="
italics
"/>
this
<
emph
type
="
italics
"/>
W
<
emph.end
type
="
italics
"/>
heel have thirty Coggs, whilſt the Screw
<
lb
/>
maketh one entire turn, it ſhall not cauſe the
<
emph
type
="
italics
"/>
W
<
emph.end
type
="
italics
"/>
heel to make more
<
lb
/>
than the thirtieth part of a turn, and if the
<
emph
type
="
italics
"/>
W
<
emph.end
type
="
italics
"/>
eight be faſtned to
<
lb
/>
a Chord that rowling about the Axis of this
<
emph
type
="
italics
"/>
W
<
emph.end
type
="
italics
"/>
heel ſhall raiſe it but
<
lb
/>
one foot in the time that the
<
emph
type
="
italics
"/>
W
<
emph.end
type
="
italics
"/>
heel makes one entire revolution,
<
lb
/>
and that the greatneſs of the Circumference of the Circle that is
<
lb
/>
deſcribed by the Force that turneth the Screw about be alſo of ten
<
lb
/>
ſeet, by reaſon that 10 times 30 make 300, one ſingle Man ſhall be
<
lb
/>
able to raiſe a
<
emph
type
="
italics
"/>
W
<
emph.end
type
="
italics
"/>
eight of that bigneſs with this Inſtrument, which
<
lb
/>
is called the Perpetual Screw, as would require 300 men with
<
lb
/>
out it.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>Provided, as before, that we thence deduct the difficulty that
<
lb
/>
we meet with in turning of it, which is not properly cauſed by the
<
lb
/>
Ponderoſity of the
<
emph
type
="
italics
"/>
W
<
emph.end
type
="
italics
"/>
eight, but by the Force or Matter of the In</
s
>
</
p
>
</
chap
>
</
body
>
</
text
>
</
archimedes
>