Aneroid barometer made of bras, enamel and glas by F Darton. Barometers measure atmospheric presure. The first succesful aneroid barometer was designed in 1844 by Lucien Vidie. An aneroid barometer contains a vacuum chamber, the expansion and contraction of which, caused by a change in air presure, forces the pointer to move. Aneroid barometers became popular with mountaineers and travellers, and as a 'weather-glas' and marine barometer.
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