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“The general scheme of Geisler’s pump is shown here. A and B are pear-shaped glass vessels connected by a long narrow india-rubber tube, which must be sufficiently strong in the body (or strengthened by a linen coating) to stand an outward pressure of 1 to 1.5 atmospheres. A terminates below in a narrow vertical tube c, which is a few inched longer than the height of the barometer, and to the lower end of this tube the india-rubber tube is attached which connects A with B. To the upper end of A is soldered a glass two-way stop-cock, by turning which the vessel A can either be made to communicate through s and a hole in the hollow cock with the vessel to be exhausted.” —The Encyclopedia Britannica, 1903


The Encyclopedia Britannica, New Warner Edition (New York, NY: The Werner Company, 1893)


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