[Arthur Holmes, geologist, and Robert W. Lawson, Einstein's English translator.] Offprint, inscribed by the authors to Prof. C. G. Curtis: 'Lead and the End Product of Thorium. (Part II.)'

16pp, 8vo, paginated 673-688. Stitched into brown wraps, with typed white label on front cover. At the head of the front cover, in manuscript: 'II | Prof C. G. Curtis | With the Authors' Compliments.' The offprint in good condition, on lightly aged paper, the brown wraps aged and chipped, with small of back wrap torn away at rear. The only other copy of this offprint on OCLC WorldCat at Durham University.