Telegraph Register

Telegraph Register

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The time service of the U.S. Naval Observatory began in 1845 when a time ball was installed above the observatory dome. Since this ball dropped each day at noon, people in sight of the Observatory could set their watches and chronometers.
The Naval Observatory bought this telegraph sounder in 1865, and used it in connection with the telegraphic time signals it would send to such local facilities as the fire alarm office, the State Department, and the Western Union Office. The “JAS J. CLARK, H. SPLITDORF NEW-YORK” inscription on the frame is that of James J. Clark and Henry Splitdorf, telegraph instrument makers who were in business together at the time. Henry Splitdorf (ca. 1834-1916) was an immigrant from Germany.
Ref: James J. Clark and Henry Splitdorf, “Improvement in Sounder Magnets,” U.S. Patent 49,857 (1865).
Currently not on view
Object Name
Telegraph Register
date made
Clark, James J.
Splitdorf, Henry
place made
United States: New York, New York City
overall: 13 cm x 5 cm x 6.75 cm; 5 1/8 in x 1 31/32 in x 2 21/32 in
overall: 6 3/4 in x 5 in x 13 1/8 in; 17.145 cm x 12.7 cm x 33.3375 cm
ID Number
catalog number
accession number
Credit Line
U. S. Naval Observatory
Science & Scientific Instruments
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History
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