Leverrier, Urbain J. J., 231, 401 Discovers Neptune, 321 Light, Rapidity of, 101 Time, Duration of, 331 Lowe at Santander, 147 Lunar craters, Antiquity of, 172 How formed, 173 Plato and Copernicus, 173 Ptolemy, 174 Schickard, 174 Tycho, 174 Lunar Mountains, How formed, 174 Lyra, Constellation, 297 Magellanic clouds, 309 Magnetism, 140, 141 Mars, 52, 373, 374 Moons of, 191 Continents of, 197 Distance from earth, 197 Maury, Lieutenant, 80 Mercury, Atmosphere, 181 Distance from sun, 49 Length of year, 180 Is it inhabited? 181 Orbit of, 180 Phases, 50 Size of, 49 Transit of, 184 Meteor, 84, 257 Meteorites, 240, 257 Around the sun, 94 August system, 90, 242 In Saturn’s rings, 94 November system, 90, 94, 241 Number of, 86 Protection from, 86 Shower of 1872, 92 Shower of 1885, 93 Milky Way, 270, 329 Mizar, 342 Modern Astronomy, 375 Moon, 62 Appearance at its full, 63 Atmosphere, 157, 169 Phases of, 160 Condition of, 65 Craters, 68, 170 Earth’s satellite, 164 Earth-shine, 160 Eclipse, 163 Influence on tides, 167 Landscape of, 68 Mountains, 67 Orbit of, 166 Temperature on, 72 Revolution, 64 Size of, 64 Surface, 67 Nasmyth, 173 Nebulæ, Number of, 336 Neptune, 59 Discovery of, 232, 234 Distance of, 123 Length of year, 59 Newton analyzes light, 385 Birth and childhood, 382 Nicetos of Syracuse, 177 Nicias, Athenian General, 146 Nicolas, Cardinal, 177 Observatories, 408 Orbits, Planetary, 47 Orion, Constellation of, 112 Parallax, 311 Phobos, Satellite of Mars, 191 Photography, Stellar, 355 Pius IX, 93 Pisa, Leaning Tower of, 378 Plane of the Ecliptic, 201 Planets, Distance from the sun, 123 First group, 48 How formed, 22 Length of years, 49 Orbits, 47 Order of formation, 23 Second group, 48,55 Plutarch, 177 Pole star, Duration of light journey, 103 Position, 108 Rate of motion, 115 Prism, 344 Pritchard, C., 356 Ptolemaic system of the universe, 175, 369 Ptolemy, 371, 369 Pythagoras, Grecian astronomer, 367 Rosse, Lord, Telescope, 406 Rowton siderite, 258 Saturn, 57 Composition of rings, 221 Distance of, 122 Distance from sun, 214 Length of year, 57 Moons, 217 Rings, 219 Satellites, 58 Size, 214 Weight, 214 Shickard, Crater on the moon, 174 Scheiner, 28 Secchi, 92 Shooting stars, 84 Sirius, Brightness of, 275, 285 Changing color, 285 Distance of, 100 Duration of light journey, 103 Movement of, 277 Solar cloud, 148 Solar System, 60, 122 Model of, 60 Spectroscope, 143, 345 Spectroscopic photography, 360 Spectrum analysis, 346, 354 Star clusters, 304, 336 Parallax, 284, 316 Spectroscopy, 356