Carbon microphone, invented in 1878 by David Edward Hughes, 1890. The apparatus was said to be so sensitive that a fly walking on the sounding-board could be heard by an observer on a telephone several miles away. Image published in 1869.
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Details
Creative#:
TOP26387396
Source:
達志影像
Authorization Type:
RM
Release Information:
須由TPG 完整授權
Model Release:
N/A
Property Release:
N/A
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No
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