Transcriber’s note: Table of Contents added by Transcriber. CONTENTS Rhythms and Geologic Time 339 The Photography of Sound Waves 354 The Psychology of Red 365 Chapters on the Stars 376 Colonies and the Mother Country (III) 390 Causes of Degeneration in Blind Fishes 397 The Evolution and Present Status of the Automobile 406 Scientific Results of the Norwegian Polar Expedition, 1893-1896 420 Discussion and Correspondence 436 Scientific Literature 439 The Progress of Science 442 THE POPULAR SCIENCE MONTHLY EDITED BY J. MCKEEN CATTELL VOL. LVII MAY TO OCTOBER, 1900 NEW YORK AND LONDON MCCLURE, PHILLIPS AND COMPANY 1900 COPYRIGHT, 1900, BY MCCLURE, PHILLIPS AND COMPANY. [Illustration: PROFESSOR R. S. WOODWARD, PRESIDENT OF THE AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE.] THE POPULAR SCIENCE MONTHLY. AUGUST, 1900. RHYTHMS AND GEOLOGIC TIME.[A] BY G. K. GILBERT, UNITED STATES GEOLOGICAL SURVEY. [A] Read to the American Association for the Advancement of Science, at New York, June 26, 1900, as the address of the retiring President.