Keywords: Seismometer (horizontal), made for the World Wide Standard Seismological Network by Spregnether Instrument Company, St. Louis, MO, 1961-1962 - National Museum of American History - DSC00020.jpg en Exhibit in the National Museum of American History Washington DC USA Photography was permitted in the museum without restriction 2015-03-27 10 39 35 own Daderot other versions cc-zero Scientific equipment in the National Museum of American History Seismometers World-Wide Standardized Seismograph Network |