File:PSM V17 D027 Carbon microphone of Elisha Gray.jpg

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Description Carbon microphone of Elisha Gray
Date
Source Popular Science Monthly Volume 17
Author Unknown authorUnknown author
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current00:03, 18 February 2014Thumbnail for version as of 00:03, 18 February 2014879 × 1,109 (179 KB)Ineuw (talk | contribs)Improved image contrast
03:46, 16 August 2010Thumbnail for version as of 03:46, 16 August 2010939 × 1,127 (165 KB)Ineuw (talk | contribs){{Information |Description = Carbon microphone of Elisha Gray |Source = http://en.wikisource.org/wiki/Page:Popular_Science_Monthly_Volume_17.djvu/27 |Date = 1880 |Author = Unknown |Permission = {{PD-old}} |other_versions = }} [[Category:Popular Sc

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