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Old 26-10-2010, 07:16 PM   #168
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1921: Earl C. Hansen invents and patents the first vacuum tube hearing aid. Called the “Vactuphone,” the instrument was battery-powered and employed a single triode.

Similar device from 1910:

edit: though it does appear that she is talking into something... great mystery i must say. i love stuff like this too!

Last edited by impotentwhitecapitalist; 26-10-2010 at 07:18 PM.
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