Salusbury, Thomas
,
Mathematical collections and translations (Tome I)
,
1667
Text
Text Image
Image
XML
Thumbnail overview
Document information
None
Concordance
Figures
Thumbnails
Page concordance
<
1 - 30
31 - 60
61 - 90
91 - 120
121 - 150
151 - 180
181 - 210
211 - 240
241 - 270
271 - 300
301 - 330
331 - 360
361 - 390
391 - 420
421 - 450
451 - 480
481 - 510
511 - 540
541 - 570
571 - 600
601 - 630
631 - 660
661 - 690
691 - 701
>
Scan
Original
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
<
1 - 30
31 - 60
61 - 90
91 - 120
121 - 150
151 - 180
181 - 210
211 - 240
241 - 270
271 - 300
301 - 330
331 - 360
361 - 390
391 - 420
421 - 450
451 - 480
481 - 510
511 - 540
541 - 570
571 - 600
601 - 630
631 - 660
661 - 690
691 - 701
>
page
|<
<
of 701
>
>|
<
archimedes
>
<
text
>
<
body
>
<
chap
>
<
p
type
="
main
">
<
s
>
<
pb
xlink:href
="
040/01/433.jpg
"
pagenum
="
411
"/>
derate the time, the Artificers that make them accomodate a
<
lb
/>
tain voluble ſtaffe horozontally, and at each end of it they
<
lb
/>
ſten two Weights of Lead, and when the time goeth too ſlow,
<
lb
/>
by the onely removing thoſe Leads a little nearer to the centre
<
lb
/>
of the ſtaffe, they render its vibrations more frequent; and on
<
lb
/>
the contrary to retard it, it is but drawing thoſe Weights more
<
lb
/>
towards the ends; for ſo the vibrations are made more ſeldome,
<
lb
/>
and conſequently the intervals of the hours are prolonged.</
s
>
</
p
>
<
p
type
="
margin
">
<
s
>
<
margin.target
id
="
marg801
"/>
<
emph
type
="
italics
"/>
The true
<
lb
/>
theſis may diſpatch
<
lb
/>
its revolutions in a
<
lb
/>
ſhorter time, in
<
lb
/>
leſſer circles than
<
lb
/>
in greater; the
<
lb
/>
which is proved by
<
lb
/>
two examples.
<
emph.end
type
="
italics
"/>
</
s
>
</
p
>
<
p
type
="
margin
">
<
s
>
<
margin.target
id
="
marg802
"/>
<
emph
type
="
italics
"/>
The firſt
<
lb
/>
ample.
<
emph.end
type
="
italics
"/>
</
s
>
</
p
>
<
p
type
="
main
">
<
s
>Here the movent vertue is the ſame, namely the counterpoiſe,
<
lb
/>
<
arrow.to.target
n
="
marg803
"/>
<
lb
/>
the moveables are thoſe ſame Weights of lead, and their
<
lb
/>
brations are more frequent when they are neerer to the centre,
<
lb
/>
that is, when they move by leſſer circles. </
s
>
<
s
>Hanging equal
<
lb
/>
Weights at unequal cords, and being removed from their
<
lb
/>
pendicularity, letting them go; we ſhall ſee thoſe that are
<
lb
/>
dent at the ſhorter cords, to make their vibrations under ſhorter
<
lb
/>
times, as thoſe that move by leſſer circles. </
s
>
<
s
>Again, let ſuch a
<
lb
/>
kind of Weight be faſtened to a cord, which cord let play upon
<
lb
/>
a ſtaple faſtened in the Seeling, and do you hold the other end
<
lb
/>
of the cord in your hand, and having given the motion to the
<
lb
/>
pendent Weight, whilſt it is making its vibrations, pull the
<
lb
/>
end of the cord that you hold in your hand, ſo that the Weight
<
lb
/>
may riſe higher and higher: In its riſing you ſhall ſee the
<
lb
/>
quency of its vibrations encreaſe, in regard that they are made
<
lb
/>
ſucceſſively by leſſer and leſſer circies. </
s
>
<
s
>And here I deſire you to
<
lb
/>
<
arrow.to.target
n
="
marg804
"/>
<
lb
/>
take notice of two particulars worthy to be obſerved. </
s
>
<
s
>One is
<
lb
/>
that the vibrations of one of thoſe plummets are made with ſuch
<
lb
/>
a neceſſity under ſuch determinate times, that it is altogether
<
lb
/>
impoſſible to cauſe them to be made under other times, unleſſe
<
lb
/>
it be by prolonging, or abreviating the cord; of which you
<
lb
/>
may alſo at this very inſtant aſcertain your ſelves by experience,
<
lb
/>
tying a ſtone to a pack-threed, and holding the other end in
<
lb
/>
your hand, trying whether you can ever by any artifice be able
<
lb
/>
to ſwing it this way and that way in other than one determinate
<
lb
/>
time, unleſſe by lengthening or ſhortening the ſtring, which
<
lb
/>
you will find to be abſolutely impoſſible. </
s
>
<
s
>The other particular
<
lb
/>
truly admirable is, that the ſelf ſame
<
emph
type
="
italics
"/>
pendulum
<
emph.end
type
="
italics
"/>
makes its
<
lb
/>
tions with one and the ſame frequency, or very little, and as it
<
lb
/>
were inſenſibly different, whether they be made by very great,
<
lb
/>
or very ſmall arches of the ſelf-ſame circumference. </
s
>
<
s
>I mean that
<
lb
/>
whether we remove the
<
emph
type
="
italics
"/>
pendulum
<
emph.end
type
="
italics
"/>
from perpendicularity one, two,
<
lb
/>
or three degrees onely, or whether we remove it 70. 80. nay to
<
lb
/>
an entire quadrant, it being let go, will in the one caſe and in
<
lb
/>
the other make its vibrations with the ſame frequency, as well
<
lb
/>
the former where it is to move by an arch of but four or ſix
<
lb
/>
grees, as the ſecond, where it is to paſſe arches of 160. or more </
s
>
</
p
>
</
chap
>
</
body
>
</
text
>
</
archimedes
>