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"This instrument consists of a glass tube of narrow bore, 16 to 17 inches long, to which is blown a glass globe 3 to 4 inches in diameter. This tube is partially filled with some colored fluid which confines the air in the flobe, a wide reservoir at the other end of the tube allows the fluid to accumulate without sensible change of level. The stand of the instrument consists of two pieces hinged together, so that the tube can be laced at a small inclination to the horizon." — Encyclopedia Britannica, 1893

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"This instrument consists of a glass tube of narrow bore, 16 to 17 inches long, to which is blown a…