Elementary natural philosophy : designed for high schools and academies (1881)
Griffin, La Roy F. (La Roy Freese), 1844-1916 · Philadelphia : Sower, Potts & Co. · leaf 143
ephone,but this diaphragm is really a very light mirror. A beamof light is alternately increased and diminished in intensityby this mirror, and this light allowed to strike a distantdiaphragm there reproduces the vibrations, either directlyor through the medium of increasing and diminishing… … Fig. 162. attached to one end, the distance of whose threads is thesame as the distance of the grooves apart. The cylinderis covered with tin foil. A thin vibrating diaphragm whichcarries a very fine needle point is so placed that the pointat rest just touches the tinfoil. 481. If now sounds be…
Physics
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