Radio-Active Substances, by Sklodowska Curie 60564 [Link: http://www.gutenberg.org/6/0/5/6/60564 ] [Files: 60564-0.txt; 60564-h.htm] Thanks to Richard Tonsing and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was produced from images generously made available by The Internet Archive) David