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      Knowledge is Power

      Scientific American April 09, 1921

      Inventions New and Interesting

      A Department Devoted to Pioneer Work in the Arts

      • April 9, 1921

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      More in the April 09, 1921 issue of Scientific American
      • Rails and Railroads
      • Two Hundred Thousand Photographs per Minute
      • Recently Patented Inventions
      View Full Contents
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