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"Theory of the barometer. Fill a glass tube (over thirty inches long and closed at one end) with mercury. The column in the tube will fall until it is only about thirty inches long. The normal pressure of the air on the contents of the bowl balances the weight of the mercury in the tube." -Foster, 1921

Barometer Theory

"Theory of the barometer. Fill a glass tube (over thirty inches long and closed at one end) with mercury.…