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EXPERIMENT II. A good Quantity of Air raised the Mercury in an open Tube, no higher than the Weight of the At∣mosphere does in a Baroscope.
HAving put a sufficient Quantity of Mercury into a large Bottle, capable of containing about ssij, we immers'd the one End of a long slender Tube, below the Surface of the Mercu∣ry; and having clos'd the Neck of the Viol with Cement, it was conveigh'd into a Receiver diffe∣rent from the former in nothing but Size; where we observ'd, that the Quantity of Air being greater in this Viol, than that made use of in the former Experiment, it was capable of ex∣panding further, and of raising the Mercury to about 29 Inches and about ⅞ out of which half an Inch being deducted, for the height it was eleva∣ted to by Air injected to try the Stanchness of the Bottle, the Spring of the Air included in the Bottle, rais'd it to 29 Inches and about ⅜; The Weight of the Air in a Baroscope at the same time, elevating the Mercury 29 Inches and ½, which was ⅛ higher than the elevated Mercury in the Receiver. But having continu'd to ply the Pump still longer, we learn'd, that the Spring of the included Air was incapable of raising it higher, than the Weight of the Atmosphere did in the Baroscope.
This Experiment was several times repeated with the like Success, but once, the Pump being ply'd more than usually, the Air contain'd in a Green Glass expanded so violently, that tho' it