261There are a large number of such repeater stations in the United States along the important telephone routes. In Fig. 136 I am showing you the location of those along the route of the famous “transcontinental telephone-circuit.” This shows also a radio-telephone connection between the coast of California and Catalina Island. Conversations have been held between this island and a ship in the Atlantic Ocean, as shown in the sketch. The conversation was made possible by the use of the vacuum tube and the bridge circuit. Part of the way it was by wire and part by radio. Wire and radio tie nicely together because both operate on the same general principles and use much of the same apparatus.
A-battery for tubes, [42]
Accumulator, [29]
Acid, action of hydrogen in, [7]
Air, constitution of, [10]
Ammeter, alternating current, [206];
calibration of, [53];
construction of, [205]