Cambridge Papers, by Walter William Rouse Ball 54023 [Link: http://www.gutenberg.org/5/4/0/2/54023 ] [Files: ; 54023-0.txt; 54023-h.htm] Thanks to Laura Wisewell, David Wilson and the Online Distributed Proofreading Team at http://www.pgdp.net (The original copy of this book was generously made available for scanning by the Department of Mathematics at the University of Glasgow.) Regards, Al