RT Journal Article SR Electronic T1 JOHN FILLMORE HAYFORD JF Science JO Science FD American Association for the Advancement of Science SP 583 OP 583 DO 10.1126/science.61.1588.583 VO 61 IS 1588 YR 1925 UL http://science.sciencemag.org/content/61/1588/583.1.abstract AB