1derate the time, the Artificers that make them accomodate a
tain voluble ſtaffe horozontally, and at each end of it they
ſten two Weights of Lead, and when the time goeth too ſlow,
by the onely removing thoſe Leads a little nearer to the centre
of the ſtaffe, they render its vibrations more frequent; and on
the contrary to retard it, it is but drawing thoſe Weights more
towards the ends; for ſo the vibrations are made more ſeldome,
and conſequently the intervals of the hours are prolonged.
tain voluble ſtaffe horozontally, and at each end of it they
ſten two Weights of Lead, and when the time goeth too ſlow,
by the onely removing thoſe Leads a little nearer to the centre
of the ſtaffe, they render its vibrations more frequent; and on
the contrary to retard it, it is but drawing thoſe Weights more
towards the ends; for ſo the vibrations are made more ſeldome,
and conſequently the intervals of the hours are prolonged.
The true
theſis may diſpatch
its revolutions in a
ſhorter time, in
leſſer circles than
in greater; the
which is proved by
two examples.
theſis may diſpatch
its revolutions in a
ſhorter time, in
leſſer circles than
in greater; the
which is proved by
two examples.
The firſt
ample.
ample.
Here the movent vertue is the ſame, namely the counterpoiſe,
the moveables are thoſe ſame Weights of lead, and their
brations are more frequent when they are neerer to the centre,
that is, when they move by leſſer circles. Hanging equal
Weights at unequal cords, and being removed from their
pendicularity, letting them go; we ſhall ſee thoſe that are
dent at the ſhorter cords, to make their vibrations under ſhorter
times, as thoſe that move by leſſer circles. Again, let ſuch a
kind of Weight be faſtened to a cord, which cord let play upon
a ſtaple faſtened in the Seeling, and do you hold the other end
of the cord in your hand, and having given the motion to the
pendent Weight, whilſt it is making its vibrations, pull the
end of the cord that you hold in your hand, ſo that the Weight
may riſe higher and higher: In its riſing you ſhall ſee the
quency of its vibrations encreaſe, in regard that they are made
ſucceſſively by leſſer and leſſer circies. And here I deſire you to
take notice of two particulars worthy to be obſerved. One is
that the vibrations of one of thoſe plummets are made with ſuch
a neceſſity under ſuch determinate times, that it is altogether
impoſſible to cauſe them to be made under other times, unleſſe
it be by prolonging, or abreviating the cord; of which you
may alſo at this very inſtant aſcertain your ſelves by experience,
tying a ſtone to a pack-threed, and holding the other end in
your hand, trying whether you can ever by any artifice be able
to ſwing it this way and that way in other than one determinate
time, unleſſe by lengthening or ſhortening the ſtring, which
you will find to be abſolutely impoſſible. The other particular
truly admirable is, that the ſelf ſame pendulum makes its
tions with one and the ſame frequency, or very little, and as it
were inſenſibly different, whether they be made by very great,
or very ſmall arches of the ſelf-ſame circumference. I mean that
whether we remove the pendulum from perpendicularity one, two,
or three degrees onely, or whether we remove it 70. 80. nay to
an entire quadrant, it being let go, will in the one caſe and in
the other make its vibrations with the ſame frequency, as well
the former where it is to move by an arch of but four or ſix
grees, as the ſecond, where it is to paſſe arches of 160. or more
the moveables are thoſe ſame Weights of lead, and their
brations are more frequent when they are neerer to the centre,
that is, when they move by leſſer circles. Hanging equal
Weights at unequal cords, and being removed from their
pendicularity, letting them go; we ſhall ſee thoſe that are
dent at the ſhorter cords, to make their vibrations under ſhorter
times, as thoſe that move by leſſer circles. Again, let ſuch a
kind of Weight be faſtened to a cord, which cord let play upon
a ſtaple faſtened in the Seeling, and do you hold the other end
of the cord in your hand, and having given the motion to the
pendent Weight, whilſt it is making its vibrations, pull the
end of the cord that you hold in your hand, ſo that the Weight
may riſe higher and higher: In its riſing you ſhall ſee the
quency of its vibrations encreaſe, in regard that they are made
ſucceſſively by leſſer and leſſer circies. And here I deſire you to
take notice of two particulars worthy to be obſerved. One is
that the vibrations of one of thoſe plummets are made with ſuch
a neceſſity under ſuch determinate times, that it is altogether
impoſſible to cauſe them to be made under other times, unleſſe
it be by prolonging, or abreviating the cord; of which you
may alſo at this very inſtant aſcertain your ſelves by experience,
tying a ſtone to a pack-threed, and holding the other end in
your hand, trying whether you can ever by any artifice be able
to ſwing it this way and that way in other than one determinate
time, unleſſe by lengthening or ſhortening the ſtring, which
you will find to be abſolutely impoſſible. The other particular
truly admirable is, that the ſelf ſame pendulum makes its
tions with one and the ſame frequency, or very little, and as it
were inſenſibly different, whether they be made by very great,
or very ſmall arches of the ſelf-ſame circumference. I mean that
whether we remove the pendulum from perpendicularity one, two,
or three degrees onely, or whether we remove it 70. 80. nay to
an entire quadrant, it being let go, will in the one caſe and in
the other make its vibrations with the ſame frequency, as well
the former where it is to move by an arch of but four or ſix
grees, as the ſecond, where it is to paſſe arches of 160. or more
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