ASTRONOMY FOR YOUNG FOLKS [Illustration: NORTHERN PORTION OF THE MOON AT LAST QUARTER Taken with 100-inch Hooker Telescope of the Mt. Wilson Observatory (See Chapter XXI)] ASTRONOMY _for_ YOUNG FOLKS BY ISABEL MARTIN LEWIS, A. M. (_Connected with the Nautical Almanac Office of the U. S. Naval Observatory_) NEW YORK DUFFIELD AND COMPANY 1922 Copyright, 1921, by THE CENTURY COMPANY Copyright, 1922, by DUFFIELD AND COMPANY Printed in U. S. A. CONTENTS CHAPTER PAGE Preface xiii I. The Constellations 3 II. January 15 III. February 21 IV. March 28 V. April 35 VI. May 41 VII. June 49 VIII. July 56 IX. August 64 X. September 71 XI. October 78 XII. November 84 XIII. December 90 XIV. Stars of the Southern Hemisphere 96 XV. The Milky Way or Galaxy 107 XVI. The Surface of the Sun 113 XVII. The Solar System 119 XVIII. The Origin of the Earth 127 XIX. Jupiter and His Nine Moons 139 XX. The Rings and Moons of Saturn 148 XXI. Is the Moon a Dead World 156 XXII. Comets 165 XXIII. Meteorites 173 XXIV. The Earth As a Magnet 183 XXV. Some Effects of the Earth's Atmosphere Upon Sunlight 193 XXVI. Keeping Track of the Moon 207 XXVII. The Motions of the Heavenly Bodies 216 XXVIII. The Evolution of the Stars--From Red Giants to Red Dwarfs 225 XXIX. Double and Multiple Stars 230 XXX. Astronomical Distances 241