. Bell telephone magazine . Delicate IcshjiJ sound iicrciiilion (tie niadc from lliis rlcrdlcd clKiir inside a citrhiiiKd s/Hicr. The riirldins. hy hrrnkittij up rcjlcriioiis from the ivdlls, f)r(r(nl llic rrrdlion of a sound pdllcrn. 64. A telephone transmitter, nornudly actuated fjy tlie voice., can aiso be actuated f)y an electric motor. Tfiis mattes it /)ossil)le. as in this picture, to estal)tish definite conditions icliicli are sut)ject to accurate measurement. 65

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Keywords: ., bookauthoramerican, bookcentury1900, bookdecade1920, bookyear1922