Engraving depicting an electrical charge being passed through a verified gas in a highly exhausted pear-shaped tube, with cathode at K), and a node at A). Ring of phosphorescence appears at P). Small piece of diamond at D) glows blue. Dated 20th Century

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Size: 3240px × 6473px
Location:
Photo credit: © World History Archive / Alamy / Afripics
License: Licensed
Model Released: No

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