WE will now proceed to obſerve that
though, by the help of the handle,
the Sucker be eaſily drawn down to the
bottom of the Cylinder; yet, without
the help of that Leaver, there would be
required to the ſame effect, a force or
weight great enough to ſurmount the
preſſure of the whole Atmoſphere: Since
otherwiſe the Air would not be driven out
of its place, when none is permitted to
ſucceed into the place deſerted by the
Sucker. This ſeems evident, from the
known Torricellian Experiment, in which,
if the inverted Tube of Mercury be but
25 Digits high, or ſomewhat more, the
Quick-ſilver will not fall but remain ſuſ
pended in the Tube; becauſe it cannot
preſs the ſubjacent Mercury with ſo great
a force, as does the incumbent Cylinder
of the Air reaching thence to the top of
the Atmoſphere: Whereas, if the Cy
linder of Mercury were three or four digits
longer, it would over-power that of the
external Air, and run out into the Veſſel'd
Mercury, till the two Cylinders came to
an Æquilibrium, and no further. Hence
we need not wonder, that though the
though, by the help of the handle,
the Sucker be eaſily drawn down to the
bottom of the Cylinder; yet, without
the help of that Leaver, there would be
required to the ſame effect, a force or
weight great enough to ſurmount the
preſſure of the whole Atmoſphere: Since
otherwiſe the Air would not be driven out
of its place, when none is permitted to
ſucceed into the place deſerted by the
Sucker. This ſeems evident, from the
known Torricellian Experiment, in which,
if the inverted Tube of Mercury be but
25 Digits high, or ſomewhat more, the
Quick-ſilver will not fall but remain ſuſ
pended in the Tube; becauſe it cannot
preſs the ſubjacent Mercury with ſo great
a force, as does the incumbent Cylinder
of the Air reaching thence to the top of
the Atmoſphere: Whereas, if the Cy
linder of Mercury were three or four digits
longer, it would over-power that of the
external Air, and run out into the Veſſel'd
Mercury, till the two Cylinders came to
an Æquilibrium, and no further. Hence
we need not wonder, that though the