Offprint entitled 'The [gamma]-Rays of Radium (B + C) and of Thorium (C + C')'.

8vo: 8 pp. With tables. In original green printed wraps. Lightly aged, but good, with two punch holes in inner margin. 'With the author's compliments' by Ellis on front wrap. Brief calculations in pencil at foot of last page. Ellis was co-author, with Rutherford and Chadwick, of 'Radiations from Radioactive Substances' (CUP, 1930), a work said by A. R. Mackintosh ('The Third Man: Charles Drummond Ellis, 1895-1980', Notes and Records of the Royal Society of London, July, 1995) to have been 'often referred to as the "Bible" of nuclear physics', with Ellis's contribution to the work placing him 'third among equals'. Mackintosh argues that Ellis's 'achievements were very great', and that he was 'among the most accomplished and important experimental physicists of the century'. He is said by Nobel-Prize-winner Sir Nevill F. Mott to have 'practically discovered the neutrino'. For further details see his entry in the New DNB.