[by] Duncan H. Looney and Sanborn C. Brown."December 4, 1953." "Reprinted from the Physical review, vol. 93, no. 5, 965-969, March 1, 1954."Includes bibliographical references.Army Signal Corps Contract No. DA36-039 sc-100, Project 8-102B-0. Dept. of the Army Project No. 3-99-10-022.