I will declare my ſelf by another example. If we ſhould ima
gine, that two cords or lines of equal thickneſs, be drawn through
two holes of equal bore; but ſo that the firſt paſs with quadruple
velocity to the ſecond: It is manifeſt, that if in a determinate
time, we ſhall by the firſt bore have drawn four Ells of the line,
in the ſame time, by the ſecond hole we ſhall have drawn but one
Ell of cord onely; and if by the firſt there paſſe twelve Ells, then
through the ſecond there ſhall paſſe onely three Ells; and in
ſhort the quantity of cord ſhall have the ſame proportion to the
cord, that the volocity hath to the velocity. And therefore we
deſiring to compenſate the tardity of the ſecond cord, and main
taining the ſame tardity to draw through the ſecond hole as much
cord as through the firſt, it will be neceſſary to draw through the
ſecond bore four ends of cord; ſo that the thickneſs of all the
cords by the ſecond hole, have the ſame proportion to the thick
neſs of the cord which paſſeth onely by the firſt, as the velocity
of the cord by the firſt hole hath reciprocally to the velocity of
the codrs by the ſecond hole. And thus its clear, that when
there is drawn through two holes equal quantity of cords in
equal time, but with unequal velocity, it will be neceſſary, that
the thickneſs of all the four cords ſhall have the ſame reciprocal
proportion to the thickneſs of the ſwifter cord, that the velo
city of the ſwifter cord hath to the velocity of the ſlower. The
which is verified likewiſe in the fluid Element of Water.
gine, that two cords or lines of equal thickneſs, be drawn through
two holes of equal bore; but ſo that the firſt paſs with quadruple
velocity to the ſecond: It is manifeſt, that if in a determinate
time, we ſhall by the firſt bore have drawn four Ells of the line,
in the ſame time, by the ſecond hole we ſhall have drawn but one
Ell of cord onely; and if by the firſt there paſſe twelve Ells, then
through the ſecond there ſhall paſſe onely three Ells; and in
ſhort the quantity of cord ſhall have the ſame proportion to the
cord, that the volocity hath to the velocity. And therefore we
deſiring to compenſate the tardity of the ſecond cord, and main
taining the ſame tardity to draw through the ſecond hole as much
cord as through the firſt, it will be neceſſary to draw through the
ſecond bore four ends of cord; ſo that the thickneſs of all the
cords by the ſecond hole, have the ſame proportion to the thick
neſs of the cord which paſſeth onely by the firſt, as the velocity
of the cord by the firſt hole hath reciprocally to the velocity of
the codrs by the ſecond hole. And thus its clear, that when
there is drawn through two holes equal quantity of cords in
equal time, but with unequal velocity, it will be neceſſary, that
the thickneſs of all the four cords ſhall have the ſame reciprocal
proportion to the thickneſs of the ſwifter cord, that the velo
city of the ſwifter cord hath to the velocity of the ſlower. The
which is verified likewiſe in the fluid Element of Water.
And to the end that this principal fundamental be well under
ſtood, I will alſo note a certain obſervation made my me in the
Art of Wyer-drawing, or ſpinning Gold, Silver, Braſs, and Iron,
and it is this; That ſuch Artificers deſiring more and more to
diſgroſſe and ſubtillize the ſaid Metals, having would about a
Rocket or Barrel, the thread of the Metal, they place the Roc
ket in a frame upon a ſtedfaſt Axis, in ſuch ſort that the Rocket
may turn about in it ſelf; then making one end of the thread to
paſſe by force through a Plate of Steel pierced with divers holes,
greater and leſſer, as need requireth, faſtning the ſame end of the
thread to another Rocket, they wind up the thread, which paſ
ſing through a bore leſs than the thickneſſe of the thread, is of
force conſtrained to diſgroſſe and ſubtillize. Now that which is
intenſly to be obſerved in this buſineſs, is this, That the parts of
the thread before the hole, are of ſuch a thickneſſe, but the parts
of the ſame thread after it is paſſed the hole, are of a leſſer thick
neſſe: and yet nevertheleſſe the maſſe and weight of the thread
which is drawn forth, is ever equal to the maſſe and weight of the
thread which is winded up. But if we ſhould well conſider the mat
ter, we ſhould finde, that the thicker the thread before the hole is,
than the thread paſſed the hole, the greater reciprocally is the
ſtood, I will alſo note a certain obſervation made my me in the
Art of Wyer-drawing, or ſpinning Gold, Silver, Braſs, and Iron,
and it is this; That ſuch Artificers deſiring more and more to
diſgroſſe and ſubtillize the ſaid Metals, having would about a
Rocket or Barrel, the thread of the Metal, they place the Roc
ket in a frame upon a ſtedfaſt Axis, in ſuch ſort that the Rocket
may turn about in it ſelf; then making one end of the thread to
paſſe by force through a Plate of Steel pierced with divers holes,
greater and leſſer, as need requireth, faſtning the ſame end of the
thread to another Rocket, they wind up the thread, which paſ
ſing through a bore leſs than the thickneſſe of the thread, is of
force conſtrained to diſgroſſe and ſubtillize. Now that which is
intenſly to be obſerved in this buſineſs, is this, That the parts of
the thread before the hole, are of ſuch a thickneſſe, but the parts
of the ſame thread after it is paſſed the hole, are of a leſſer thick
neſſe: and yet nevertheleſſe the maſſe and weight of the thread
which is drawn forth, is ever equal to the maſſe and weight of the
thread which is winded up. But if we ſhould well conſider the mat
ter, we ſhould finde, that the thicker the thread before the hole is,
than the thread paſſed the hole, the greater reciprocally is the
zoom in
zoom out
zoom area
full page
page width
set mark
remove mark
get reference
digilib