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EXPERIMENT XXI, About the subsiding of Mercury in the Tube of the Torrecellian Experiment, to the Level with the Superficies of the Stagnant Mercury.
THE lower Part of the Ball of a Bolt-head being circularly cut off, we made use of it for a Receiver, including a Baroscope in it, and upon the first Exsuction, the Mercury subsided from 29 Inches to 9 or 10, and by three Exsu∣ctions more, would be brought to a Level with the Stagnant Mercury, but would rise to it's first Station again, as the Air was admitted in flower or faster.
In which Experiment it is to be noted; First, that upon the first Exsuction, the Mercury was brought within an Inch of the Bottom, and con∣tinu'd several successive Vibrations before it set∣led at 10 Inches high. Secondly. If instead of drawing any out, Air be forced into the Recei∣ver, it will raise the Mercury higher than it's former Station: Thirdly, The Receiver was so far exhausted, as to make the Mercury subside to a Level.