Physical Review, Vol. XXVIII, No. 4, April, 1909, pages 277-290Hovda, Olaf2016-03-092016-03-091909-05https://hdl.handle.net/11299/178194University of Minnesota Masters thesis. May 1909. 1 computer file (PDF); pages 277-290. Reprinted in Physical Review.enThesis or Dissertation