Section I.—History.

Page Frontispiece—THE OBSERVATORY AT NICE 2

SECTION II.—GEOMETRICAL ASTRONOMY.

Frontispiece—THE LICK REFRACTOR OF THIRTY-SIX INCHES APERTURE 40 Fig. 1.— ROUGH MEASUREMENT OF EARTH’S DIAMETER 43 2.— HORIZONS AT TWO PLACES ON THE EARTH 44 3.— FOUCAULT’S PENDULUM EXPERIMENT 49 4.— SUN’S RAYS—DAY AND NIGHT 52 5.— ATMOSPHERIC REFRACTION 54 6.— APPARENT PATHS OF SUN AT EQUINOXES AND SOLSTICES 56 7.— ABERRATIONAL ORBIT OF A STAR 58 8.— THE SUN’S ALTITUDE IN SUMMER AND WINTER 62 9.— THE SUN’S ALTITUDE AT THE EQUINOXES 63 10.— THE MIDNIGHT SUN 64 11.— ALTITUDE AND AZIMUTH 66 12.— RIGHT ASCENSION, DECLINATION, ETC. 69 13.— ELLIPTIC FORM OF EARTH’S ORBIT 72 14.— THE ELLIPSE 73 15.— HOW TO DRAW AN ELLIPSE 74 16.— ILLUSTRATING KEPLER’S SECOND LAW 76 17.— EFFECT OF OBLIQUITY OF ECLIPTIC UPON THE EQUATION OF TIME 81 18.— THE MOON’S PHASES 90 19.— THE LUNAR MONTH 91 20.— THE MOON’S ROTATION 93 21.— THE MOON’S NODES 94 22.— POSITION OF ECLIPTIC AT SUNSET AT VERNAL EQUINOX 96 23.— MOVEMENT OF AN INTERIOR PLANET 99 24.— MORNING AND EVENING STARS 100 25.— MOVEMENT OF AN EXTERIOR PLANET 103 26.— APPARENT PATHS OF CERES, PALLAS, JUNO, AND VESTA, IN 1896 104 27.— OPPOSITION OF MARS 105 28.— ELEMENTS OF AN ELLIPTIC ORBIT 107 29.— THE EARTH’S SHADOW 110 30.— THE LUNAR ECLIPTIC LIMIT 112 31.— ECLIPSES OF THE SUN 114 32.— DURATION OF A SOLAR ECLIPSE 115 33.— TRACK OF ECLIPSE OF APRIL 16, 1893 117 34.— DETERMINATION OF LATITUDE 124 35.— ANCIENT MODE OF MEASURING LATITUDE 125 36.— TRIANGULATION 132 37.— MOVEMENTS OF THE EARTH’S POLE, 1890–95 138 38.— PARALLAX OF A HEAVENLY BODY 140 39.— DIAMETER OF A HEAVENLY BODY 142 40.— MEASUREMENT OF THE MOON’S DISTANCE 143 41.— RELATIVE DISTANCE OF VENUS 145 42.— THE PARALLAX OF MARS 147 43.— THE TRANSIT OF VENUS 148 44.— THE MOON’S CURVILINEAR PATH 155 45.— THE TIDES 163 46.— NUTATION 169 47.— SECTION OF READING MICROSCOPE 172 48.— THE READING MICROSCOPE 173 49.— THE ACHROMATIC OBJECT-GLASS 177 50.— THE NEWTONIAN REFLECTOR 179 51.— THE CASSEGRAIN REFLECTOR 181 52.— THE PHOTOGRAPHIC TELESCOPE 196 53.— THE MERIDIAN CIRCLE OF THE PARIS OBSERVATORY 203 54.— THE MICROMETER APPLIED TO A BINARY STAR 208 55.— THE SPECTROSCOPE ADAPTED TO THE EYE END OF THE LICK TELESCOPE 221