2 photos

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• Identified! [Daniel W. Kessler of the National Bureau of Standards with device used to test slabs of marble over long periods of time] ? (LOC)

  • Uploaded by: The Library of Congress
  • License: No known copyright restrictions
  • 15 comments
  • 35 favorites
  • 22,812 views
  • Date taken: 1925
  • Date uploaded: 2015-10-02
  • Tags: libraryofcongress, dc:identifier=httphdllocgovlocpnphec45047, xmlns:dc=httppurlorgdcelements11, danielwkessler, bureauofstandards, dwkessler, stone, testing, apparatususedformakinglongperiodscrubbingtestsonmarble, mysterysolved
  • Visibility: public
• Identified! [Testing airplane lenses used in map making at the U.S. Bureau of Standards, Washington, D.C.] (LOC)

  • Uploaded by: The Library of Congress
  • License: No known copyright restrictions
  • 18 comments
  • 8 favorites
  • 19,159 views
  • Date taken: 1934
  • Date uploaded: 2015-10-02
  • Tags: libraryofcongress, dc:identifier=httphdllocgovlocpnphec37556, xmlns:dc=httppurlorgdcelements11, lenstesting, bureauofstandards, aerialmapping, determining, focallength, distortion, mysterysolved, frankacase
  • Visibility: public