CONTENTS
| CHAPTER | PAGE |
| [I.—Different kinds of measurement] | [1] |
| The measurement of angles and time. | |
| [II.—The stars and their diurnal motion] | [10] |
| Finding the stars—Their apparent motion—Latitude—Direction of the meridian—Sidereal time—Definitions. | |
| [III.—Fixed and wandering stars] | [29] |
| Apparent motion of the sun, moon, and planets—Orbits of the planets—How to find the planets. | |
| [IV.—Celestial mechanics] | [46] |
| Kepler's laws—Newton's laws of motion—The law of gravitation—Orbital motion—Perturbations—Masses of the planets—Discovery of Neptune—The tides. | |
| [V.—The earth as a planet] | [70] |
| Size—Mass—Precession—The warming of the earth—The atmosphere—Twilight. | |
| [VI.—The measurement of time] | [86] |
| Solar and sidereal time—Longitude—The calendar—Chronology. | |
| [VII.—Eclipses] | [101] |
| Their cause and nature—Eclipse limits—Eclipse maps—Recurrence and prediction of eclipses. | |
| [VIII.—Instruments and the principles involved in their use] | [121] |
| The clock—Radiant energy—Mirrors and lenses—The telescope—Camera—Spectroscope—Principles of spectrum analysis. | |
| [IX.—The moon] | [150] |
| Numerical data—Phases—Motion—Librations—Lunar topography—Physical condition. | |
| [X.—The sun] | [178] |
| Numerical data—Chemical nature—Temperature—Visible and invisible parts—Photosphere—Spots—Faculæ—Chromosphere—Prominences—Corona—The sun-spot period—The sun's rotation—Mechanical theory of the sun. | |
| [XI.—The planets] | [212] |
| Arrangement of the solar system—Bode's law—Physical condition of the planets—Jupiter—Saturn—Uranus and Neptune—Venus—Mercury—Mars—The asteroids. | |
| [XII.—Comets and meteors] | [251] |
| Motion, size, and mass of comets—Meteors—Their number and distribution—Meteor showers—Relation of comets and meteors—Periodic comets—Comet families and groups—Comet tails—Physical nature of comets—Collisions. | |
| [XIII.—The fixed stars] | [291] |
| Number of the stars—Brightness—Distance—Proper motion—Motion in line of sight—Double stars—Variable stars—New stars. | |
| [XIV.—Stars and nebulæ] | [330] |
| Stellar colors and spectra—Classes of stars—Clusters—Nebulæ—Their spectra and physical condition—The Milky Way—Construction of the heavens—Extent of the stellar system. | |
| [XV.—Growth and decay] | [358] |
| Logical bases and limitations—Development of the sun—The nebular hypothesis—Tidal friction—Roche's limit—Development of the moon—Development of stars and nebulæ—The future. | |
| [Appendix] | [383] |
| [Index] | [387] |