Notation on back, "Beneath 125 feet of limestone three quarters of a mile within the Endless Caverns of New Market, Virginia, three scientists of the Rouss Physical laboratory, Univerisity of Virginia, Charlottesville, Virginia, are intent upon recordings of cosmic rays which have penetrated to this depth beneath the earth's surface. Left to right: James L. Young, III, Professor L.B. Snoddy, Professor E. P. Ney. In front of Dr. Snoddy is shown the unshielded spherical ionization chamber which automatically records ionization produced by cosmic rays. On the right is the Geiger-Mueller Counter with an oscillograph which records the frequency of the rays upon paper tape which Mr. Young is examining."
Special Collections, University of Virginia Library, Charlottesville, Va.