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EXPERIMENT XXXIV. Bellows whose Nose is very well stopp'd, will open of their own accord, when the Pressure of the Exter∣nal Air is taken off.
AS an Argument of the great Force of the Air's Weight, it is observ'd, that when the Nose of a Pair of Bellows is stopp'd, it re∣quires a Force able to overpower the Pressure of so large a Pillar of Air, as lies upon them, to open them; but when that Weight of the Atmosphere is taken off, the Spring of the Included Air is so strong, as to be able to raise and expand the Bellows of it's own accord.
To make this Evident,* 1.1 we caus'd a Pair of Bellows to be made, whose Boards were circu∣lar, and near 6 Inches Diameter, without a Valve, the Nose of them being about an Inch long, and the Leather limber: Which Bellows, when full of Air, seem'd to be a Cylinder of about 18 Inches high.
The Nose of these Bellows being stopp'd, when they were empty'd of Air, we convey'd them into our Receiver, and observ'd, that when the Air was exhausted out of the Receiver, the Air con∣tain'd in the Folds of the Bellows, and betwixt the two Bases lifted up the Higher a considerable Height.