Category:Electrical Experimenter, 1920

Media in category "Electrical Experimenter, 1920"

The following 3 files are in this category, out of 3 total.

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  Audion applications Electrical Experimenter Feb 1920 pg1001.png 739 × 1,040; 349 KB
  
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  Galton whistle.jpg 502 × 429; 35 KB
  
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  Plaskett telescope Dominion Astrophysical Observatory Canada 1920.jpg 481 × 692; 65 KB