Duplex Pendulum Seismograph
date: label: date made
content: late 1880s
name: label: maker
content: California Electrical Works
notes: label: Description
content: A paper label on this seismograph reads “Made from the Designs of Professor Ewing of Dundee, by the California Electric Works, 35 Market street, San Francisco; and recommended for use in California by Professor LeConte of Berkeley and by Professor Holden, Director of the Lick Observatory.”
label: Description
content: James Alfred Ewing was a young Scottish physicist/engineer who, while teaching in Tokyo in the years between 1878 and 1883, designed several seismographs. Among these was a duplex pendulum instrument that recorded the two horizontal components of earthquakes. It was, he claimed, “comparatively cheap and simple” and was “employed by many private observers in Japan.”
label: Description
content: The Cambridge Scientific Instrument Company in England began manufacturing Ewing’s several seismographs in 1886. The first examples in the United States were installed in the Lick Observatory on Mount Hamilton and in the University of California at Berkeley. Edward Holden was then director of the former and president of the latter, and Joseph LeConte was professor of geology at Berkeley.
label: Description
content: Enthusiastic about the new science of seismology, Holden and LeConte convinced Paul Seiler, head of an electrical apparatus supply firm in San Francisco, to manufacture duplex pendulum seismographs that would sell for $15 apiece (rather than the $75 charged by the English firm). Over a dozen examples are known to have been distributed across the country and around the world, some recording earthquakes as early as 1889. This one came to the Smithsonian in 1964, a gift of Case Institute of Technology in Cleveland, Ohio.
label: Description
content: Ref: Edward S. Holden, <i>Handbook of the Lick Observatory</i> (San Francisco, 1888), pp. 54-56.
label: Description
content: Edward S. Holden and Joseph LeConte, “Use of the Ewing Duplex Seismometer” (1887), reprinted in Holden, “Earthquakes on the Pacific Coast,” <i>Smithsonian Miscellaneous Collections</i> 1087 (1898).
label: Location
content: Currently not on view
place: label: place made
content: United States: California, San Francisco
label: used
content: United States: Ohio, Cleveland
setName: label: See more items in
content: Medicine and Science: Physical Sciences
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content: Seismographs
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content: Science & Mathematics
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content: Measuring & Mapping
creditLine: label: Credit Line
content: Case Institute of Technology
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.323669
label: catalog number
content: 323669
label: accession number
content: 251332
objectType: label: Object Name
content: seismograph
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: paper (label on top of the instrument material)
label: Physical Description
content: brass (overall material)
label: Measurements
content: overall: 27 1/8 in x 13 1/2 in x 11 3/4 in; 68.8975 cm x 34.29 cm x 29.845 cm