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• Vibrating hair spring. Hair spring is placed into a vibrating machine and operator selects the hair spring with an elastcity which would vibrate a balance wheel with period of 18,000 times per hour, 1936

  • Uploaded by: U.S. National Archives
  • License: No known copyright restrictions
  • 0 comments
  • 7 favorites
  • 12,143 views
  • Date taken: 1936
  • Date uploaded: 2012-07-03
  • Tags: nara:arcid=518442, usnationalarchives, lewishine, thegreatdepression, lancaster, pennsylvania, 1936
  • Visibility: public