Page:In the high heavens.djvu/384

380 Jupiter,  size and weight of his satellites, 43, 115 the four satellites known to the Chinese, 95 why the satellites are not distinguishable, 96-99 their distances and periods of revolution, 110 discovery of the fifth satellite, 99, 105 lustre, size, distance, period of the fifth satellite, 107-108 orbit of the fifth satellite, 112 the problem of the satellites, 101 the work of Laplace, 102 interest of the discovery, 100, 103 value of the discovery, 104, 109 Kepler' s law, 109-110

spectrum measurements, 160-162 Kepler's law and Jupiter's fifth satellite, 109

, Prof., on the waste of solar heat, 263 on the extinction of the sun, 274-275 Laplace and the satellite system of Jupiter, 102 the Nebular Hypothesis, 212, 217-219 Latitude, how to find, 69 value of, in observatories, 171, 73-76 Lexell's comet in collision with Jupiter, 306 Lick telescope and recent discoveries, 104, 105 its practical power, 138 Lockyer's theory as to comets and meteorites, 308 Lyræ Delta, the point to which the solar system is moving, 25 Epsilon, 201

, is he possible on any other globe? 44-51 the destiny of species, 253-256 heat essential to life, 259 sources of heat, 261-263 limit to the sun's duration, 272 extinction of the race, 274-275 Mars in the carboniferous era, 19 conditions of life on, 50-51 discovery of the satellites, 99 orbits of the satellites, 117 orbit of Mars, 116 its distance from the earth, 117 favourable oppositions, 117 their recurrence, 120 Mars compared with the moon, 121 compared with Venus, 121 the most world-like of the planets, 124 dimensions and weight of Mars, 124 atmosphere, 125-137 its atmosphere compared with earth's, 135-136 composition of its atmosphere, 136-137 the gases on Mars, 133 Mars the smallest planet containing air and water, 134 clouds on Mars, 135 water on Mars, 137 Mars through the telescope, 138, 140 its polar snows, 140-141 its "canals," 141-142, 144 the stage of physical evolution on Mars, 145 life and intelligence, 145-147 Schiaparelli's observations, 141 observations of Terby and Perrotin, 142 Meteors, connection with comets, 167, 297-298 difference between meteors and meteorites, 167, 296-297 the Leonids, 168, 295, 297 the "radiant," 298 Meteorites, character of, 295, 296