Tests indicate radio waves penetrate earth and rock

Tests conducted by the United States Bureau of Mines, Department of Commerce, in a Colorado metal mine indicate strongly that radio waves will penetrate 500 feet or more of rock strata. These preliminary experiments were observed by Dr. A. S. Eve, Director of the Department of Physics, McGill University, Montreal, Canada, who is conducting a study for the Bureau of Mines of the possibilities of various methods of geophysical prospecting for the location of underground mineral deposits.