Ferrel Tide Predictor

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
Object Name
harmonic synthesizer
Date made
used during
Fauth & Co.
Ferrel, William
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
Place Made
United States: District of Columbia, Washington
ID Number
catalog number
accession number
Science & Mathematics
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Transfer from U. S. Coast and Geodetic Survey
Additional Media

Visitor Comments

Add a comment about this object

**Please read before submitting the form**

Have a comment or question about this object to share with the community? Please use the form below. Approved comments will appear on this page and may receive a museum response (but we can't promise). Please note that we generally cannot answer questions about your own artifacts or comment on their value, rarity, or collectibility.

Have a question about anything else, or would you prefer a personal response? Please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Enter the characters shown in the image.