A Simple Polarity Indicator for Indicating the Negative pole of an electric Current

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'A Simple Polarity Indicator for Indicating the Negative pole of an electric Current' (1904). Artist/photographer: Unsigned. Provenance: "Scientific American". Type: Antique halftone photographic print.

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Size: 1842px × 1516px
Photo credit: © Antiqua Print Gallery / Alamy / Afripics
License: Royalty Free
Model Released: No

Keywords: 1904, 20th, antique, century, current, electric, halftone, indicating, indicator, negative, photographic, polarity, pole, print, simple, twentieth, vintage