1ed, deſerves the name of a true Vacuum,
and though we cannot yet perfectly free
it from Air it ſelf, yet we thought fit to
try how far the Air would manifeſt its
gravity in ſo thin a medium, as we could
make in our Receiver, by evacuating it.
We cauſ'd then to be blown at the Flame
of a Lamp, a Glaſs-bubble of about
the bigneſs of a small Hen egge, and of
an Oval form, ſave that at one end there
was drawn out an exceeding flender Pipe,
that the Bubble might be ſeal'd up, with
as little rarifaction as might be, of the
Air included in the great or ovall Cavi-
ty of it.This Glaſs being ſeal'd, was fa-
ſtened to one of the Scales of the exact
pair of Ballances formerly mention'd;
and being counterpoiſ'd with a weight of
Lead, was convey'd into the Receiver,
and cloſ'd up in it.The Beam appearing
to continue Horizontal, the Pump was ſet
awork, and there ſcarce paſt above two
or three Exſuctions of the Air, before
the Ballance loſt its Aequilibrium, and
began to incline to that ſide on which
the Bubble was; which, as the Air was
further and further drawn out, did mani-
feſtly more and more preponderate, till
he that pump'd began to grow weary of
and though we cannot yet perfectly free
it from Air it ſelf, yet we thought fit to
try how far the Air would manifeſt its
gravity in ſo thin a medium, as we could
make in our Receiver, by evacuating it.
We cauſ'd then to be blown at the Flame
of a Lamp, a Glaſs-bubble of about
the bigneſs of a small Hen egge, and of
an Oval form, ſave that at one end there
was drawn out an exceeding flender Pipe,
that the Bubble might be ſeal'd up, with
as little rarifaction as might be, of the
Air included in the great or ovall Cavi-
ty of it.This Glaſs being ſeal'd, was fa-
ſtened to one of the Scales of the exact
pair of Ballances formerly mention'd;
and being counterpoiſ'd with a weight of
Lead, was convey'd into the Receiver,
and cloſ'd up in it.The Beam appearing
to continue Horizontal, the Pump was ſet
awork, and there ſcarce paſt above two
or three Exſuctions of the Air, before
the Ballance loſt its Aequilibrium, and
began to incline to that ſide on which
the Bubble was; which, as the Air was
further and further drawn out, did mani-
feſtly more and more preponderate, till
he that pump'd began to grow weary of