<< >>
Usage conditions apply
This variometer measures slight changes in the vertical component of the earth's magnetic field. The surrounding Helmholtz coil enables its scale value to be determined electrically. This example is marked "RUSKA INSTRUMENT CORPORATION HOUSTON TEXAS No. 5728 MADE IN U.S.A." The U.S. Coast and Geodetic Survey acquired it in 1957, probably for use during the International Geophysical Year. The U.S. Geolgical Survey acquired it in 1973 when it assumed responsibility for the geomagnetic program of the federal government, and transferred it to the Smithsonian in 1982.
Ref: Ruska Instrument Corporation, Magnetic Instruments (Houston, 1955).
Currently not on view
Object Name
Ruska Instrument Corporation
Place Made
United States: Texas, Houston
Physical Description
metal (overall material)
overall: 19 in; 48.26 cm
overall: 8 7/8 in x 12 1/4 in; 22.5425 cm x 31.115 cm
ID Number
accession number
catalog number
Credit Line
U.S. Department of the Interior, U.S. Geological Survey
Science & Scientific Instruments
Science & Scientific Instruments
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Science & Mathematics
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object