Transcriber’s note: Table of Contents added by Transcriber. CONTENTS Chapters on the Stars 227 Preventive Inoculation. (II.) 240 Colonies and the Mother Country. (II.) 248 Technical Education at the Massachusetts Institute of Technology 257 The Psychology of Crazes 285 Some Phases of the Earth’s Development in the Light of Recent Chemical Research 295 A Preliminary Account of the Solar Eclipse of May 28, 1900, As Observed by the Smithsonian Expedition 302 Malaria and the Malarial Parasite 310 New Sources of Light and of Röntgen Rays 318 Discussion and Correspondence 323 Scientific Literature 327 The Progress of Science 332 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: PRESIDENT G. K. GILBERT, AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE.] THE POPULAR SCIENCE MONTHLY. JULY, 1900. CHAPTERS ON THE STARS. BY PROFESSOR SIMON NEWCOMB. I. INTRODUCTORY.