Excerpt from Scientific Papers, Vol. 4: Periodic Orbits and Miscellaneous Papers An appendix at the end of the volume contains, by permission of the Royal Statistical Society, two papers on the marriage of cousins written many years ago. As, even after the lapse of 36 years, I still receive letters on the subject, it seemed advisable to include them in this collection, although they are biological in character. The chronological list of papers is again repeated, and a complete list is given of all the errata hitherto discovered in the four volumes, some of them of course being repeated from the previous volumes. So accurate has been the work of the compositors and readers that typographical mistakes are hardly to be found, and I feel greatly indebted to them for their care. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.