Ferrel Tide Predictor

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In 1872, the British physicist William Thomson (later Lord Kelvin) devised a machine to simulate mechanically the combination of periodic motions that produce tides. Inspired by this example, William Ferrel of the U.S. Coast and Geodetic Survey designed a tide predictor and had it built by the Washington, D.C., firm of Fauth and Company. This elegant machine was more compact than that of Thomson, and gave maxima and minima rather than a continuous curve as output. It was designed in 1880, went into service in 1883 and remained in use until 1910. The success of Ferrel's tide predictor suggested the feasibility of replacing calculations performed by people with computation by machines.
Currently not on view
National Museum of American History
Fauth & Co.
Ferrel, William
Credit Line
Transfer from U. S. Coast and Geodetic Survey
Physical Description
wood (overall material)
metal (overall material)
glass (overall material)
overall: 62.2 cm x 46.5 cm x 34.3 cm; 24 1/2 in x 18 5/16 in x 13 1/2 in
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Medicine and Science: Mathematics
Science & Mathematics
Place Made
United States: District of Columbia, Washington
used during
Object Name
harmonic synthesizer
ID Number
catalog number
accession number