none of the Air been drawn away from a­<lb/> bout the Needle, which when the Load­<lb/> &longs;tone was removed, after &longs;ome tremu­<lb/> lous Vibrations to and fro, re&longs;ted in a po­<lb/> &longs;ition wherein it look'd North and <lb/> South. </s></p>
<p type="main">
<s>PRoceed we now to the mention of <lb/> <arrow.to.target n="marg19"/><lb/> that Experiment, whereof the &longs;ati&longs;­<lb/> factory tryal was the principal Fruit I <lb/> promi&longs;'d my &longs;elf from our Engine. </s>
<s>It <lb/> being then &longs;ufficiently known, that, in <lb/> the Experiment <emph type="italics"/>De Vacuo,<emph.end type="italics"/> the Quick­<lb/> &longs;ilver in the Tube is wont to remain ele­<lb/> vated, above the &longs;urface of that whereon <lb/> it leans, about 27 digits: I con&longs;idered, <lb/> that, if the true and onely rea&longs;on why the <lb/> Quick-&longs;ilver falls no lower, be, that at <lb/> that Altitude, the Mercurial Cylinder in <lb/> the Tube, is an <emph type="italics"/>Æquilibrium<emph.end type="italics"/> with the <lb/> Cylinder of Air, &longs;uppo&longs;'d to reach from <lb/> the adjacent Mercury to the top of the <lb/> Atmo&longs;phere: If this Experiment could <lb/> be try'd out of the Atmo&longs;phere, the <lb/> Quick-&longs;ilver in the Tube would fall <lb/> down to a levell with that in the Ve&longs;&longs;el, <lb/> &longs;ince then there would be no pre&longs;&longs;ure up­<lb/> on the Subjacent, to re&longs;i&longs;t the weight of
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