Technical World, May, 1906, pages 326-327:

Underground  Wireless  Telegraphy
MANY a man can "talk through his hat," and that apparently without supreme effort or without any complicated mechanical device contrived to facilitate the process. To talk through the earth, however, is to overcome a more substantial obstacle. A method of doing so, without the use of wires or other specially installed conductors, has, after years of experiment, been invented by Father Joseph Murgas of the Slavonic Catholic church, Wilkesbarre, Pa., who claims that before long he will be able to send wireless messages underground to Europe.
    For the purpose of long-distance communication, a shaft 3,000 feet deep will be sunk here, and a similar shaft in Europe. Each shaft will be walled with concrete to guard it from dampness; and wires leading some distance into the earth from the shafts will be incased in iron or steel tubing. High power will be required to generate the transmitting waves; and the inventor will use a special signal system of his own invention, which replaces the Morse signals used by other wireless systems, with musical tones, each indicating a letter of the alphabet in the code word or group of words, and thus giving greater rapidity of operation than the Morse system.
    Satisfactory results have attended tests with shallow shafts and small power, between points that are situated a few miles apart.
Joseph Murgas