. Bell telephone magazine . r DcForcst T/iree- c I c VI r n t Tube: 190S. High Vacuum Trie phoneRepcatir: 1Q13. USA TT. M 0 d c r n Telephone Repeater: 1927. Arnold Mercury ArcRepeater: 1912. 25 WattA i r-cooledPower Tubefor Trans-atlanticTests:1915.

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Keywords: ., bookauthoramerican, bookcentury1900, bookdecade1920, bookyear1922