International, date-line, explained, 126 geodetic association, 139 Inter-stellar motion, in clusters, 98 in Pleiades, 14 Islands of Pacific, their longitude and time, 125 Japan, latitude station in, 139 Jewellers' correct time, 121 Journalistic astronomy, 176 Jupiter's satellites, discovered by Galileo, 50 discovered by Barnard, 51 Keeler, observes Saturn's rings, 140, 147, 150 photographs nebulæ, 32 "Keyhole" nebula, 205 Lambert, determines longitude of Washington, 168 Laplace, discusses Saturn's rings, 146 nebular hypothesis, 33 stability of solar system, 210 Latitude, changes of, 133, 138 definition of, 134 determining the, 6 Leverrier, predicts discovery of Neptune, 61, 142 Lick Observatory, Keeler's observations, 140 Light, undulatory theory of, 19, 148 Light-waves, measuring length of, 20, 149 Logogriph, by Huygens, 143 Long-exposure photography, 85 Longitude, counted East and West, 125 determining, 6 determining by occultations, 167 effect on time differences, 123 explained, 123 of Washington, first determined, 168 Maclear, observes Eta Argus, 205 Magnitudes, stellar, 91 Manila, its time, 127 Maps, astronomical side of, 112 Meridian circle, explained, 189 Milky-way, poor in nebulæ, 33 Minor Planets, see Asteroids. MOON, HOAX, 199 motion among stars, 163 mountains discovered by Galileo, 49 size of, measured, 166 Motion of moon, 163 MOTIONS of the EARTH'S Pole, 131 MOUNTING GREAT TELESCOPES, 170 Naked-eye nebulæ, 28 Naples, Royal Observatory, latitude observations, 139 Naval Observatory, Washington, noon signal, 120 NAVIGATION, 1 before chronometers, 3 use of astronomy in, 113 NEBULÆ, 27 Nebula, in Andromeda, 28 in Orion, 30 "keyhole", 205 Nebular, hypothesis, 33 structure in Pleiades, 17 Nebulous stars, 31 Negative, and positive, in photography, 82 Neptune, discovery predicted by Leverrier, 61, 142 discovery by Galle, 61 Newcomb, fixes apex of solar motion, 222 Newton, law of gravitation, 212 longitude commission, 8 New York, its telegraphic time system, 120 Noon Signal, Washington, 120 Number, of nebulæ, 31, 33 of temporary stars, 38 Nutation, explained, 188 Occultations, 161 explained, 165 Occultations, use of, 166, 167 Orion nebula, 30 Pacific islands, their longitude and time, 125 Parallax, solar, 67, 106 stellar, 94, 106 measured with heliometer, 158 Paris, congress of astronomers, 1887, 102 exposition of 1900, 176 Periodic motion of earth's pole, 133 Perseus, constellation, temporary star in, 46 Philippine Islands, their time, 127