Experiments in underground communication through earth strata
Contributors: Freeman, Howard Bassett, 1889- joint author.; Zellers, Donald Henry, 1904- joint author.
Publisher: U.S. Govt. print. off.
Published: 1928
Place of publication: Washington
Language: eng
Number of pages: 60
Subjects: Mine rescue work.; Coal mines and mining.; Signals and signaling.
Other titles: Underground communication through earth strata.