Carnotite Ores and the Supply of Radium

Abstract

IN NATURE for October 25, 1917, there appeared a review of Dr. P. E. Browning's book, “Introduction to the Rarer Elements.” A special chapter devoted to the radio-elements was contributed by me, and in commenting on this section the reviewer takes exception to a statement that “the chief source of radium has been the minerals containing a higher proportion of uranium, principally carnotite, and the present supply has been largely obtained from the carnotite ores of south-western Colorado.” Since the comments of the reviewer suggest the possibility of an even more widespread misconception of the true conditions, I am taking the liberty of mentioning some of the facts upon which the above statement is based.