1the Tube totally to ſubſide; becauſe,
when the Receiver was conſiderably em
pty'd of its Air, and conſequently that
little that remain'd grown unable to reſiſt
the Irruption of the external, that Air
would (in ſpight of whatever we could
do) preſs in at ſome little Avenue or
other; and though much could not there
at get in, yet a little was ſufficient to coun
terballance the preſſure of ſo ſmall a Cy
linder of Quick-ſilver, as then remain'd
in the Tube.
when the Receiver was conſiderably em
pty'd of its Air, and conſequently that
little that remain'd grown unable to reſiſt
the Irruption of the external, that Air
would (in ſpight of whatever we could
do) preſs in at ſome little Avenue or
other; and though much could not there
at get in, yet a little was ſufficient to coun
terballance the preſſure of ſo ſmall a Cy
linder of Quick-ſilver, as then remain'd
in the Tube.
Now (to ſatisfie our ſelves further, that
the failing of the Quick-ſilver in the
Tube to a determinate height, proceeds
from the Æquilibrium, wherein it is at
that height with the external Air, the one
gravitating, the other preſſing with equal
force upon the ſubjacent Mercury) we Re
turned the Key and let in ſome new Air;
upon which the Mercury immediatly be
gan to aſcend (or rather to be impell'd up
wards) in the Tube, and continu'd aſcend
ing, till having Return'd the Key it im
mediatly reſted at the height which it had
then attain'd: And ſo, by Turning and
Returning the Key, we did ſeveral times
at pleaſure impel it upwards, and check its
aſcent. And laſtly, having given a free
the failing of the Quick-ſilver in the
Tube to a determinate height, proceeds
from the Æquilibrium, wherein it is at
that height with the external Air, the one
gravitating, the other preſſing with equal
force upon the ſubjacent Mercury) we Re
turned the Key and let in ſome new Air;
upon which the Mercury immediatly be
gan to aſcend (or rather to be impell'd up
wards) in the Tube, and continu'd aſcend
ing, till having Return'd the Key it im
mediatly reſted at the height which it had
then attain'd: And ſo, by Turning and
Returning the Key, we did ſeveral times
at pleaſure impel it upwards, and check its
aſcent. And laſtly, having given a free
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