Frauenhofer, 171 Galileo, 101 Giacobini, 97 God, 174 Gravitation, 105, 124 Gruithuisen, 100 Guzmann, prize, 153 Habitability of planets, 170 Harding, 101 Hercules, 160, 162 Homer, 95 Huygens, 185 Invisible universe, 175 Jupiter, 23, 41, 123, 125, 187; (red spot), 126 Juvisy Observatory, 107, 135, 138 Kant, 182 Kircher, 184 Leibnitz, 166 Life, conditions, of, 106 Littrow, J. von, 141, 145 Magnetic variations, 131 Magnetic storms, 134 Mars, 14,105, 111, 145, 187, 204; communication with, 117; flashes on, 111; polar snows, 113; rotation, 114 Materialism, 173 Mayer, 101 Mercury, 185, 203 Milky Way, 163, 170 Molecules, 164 Moon, 9, 41, 105, 116, 141, 201 Neptune, 20, 35, 41, 219 Nice Observatory, 97 Pascal, 168 Renan, 88 Saturn, 18, 41, 189 Scheiner, 181, 192, 195, 210, 215, 220 Silicon, 210 Sirius, 47 Spectrum analysis, 127, 200 Stars and atoms, 157 Stars, speed of, 159 Sunspots, 134, 135 Temperature of planets, 127, 197 Venus, 95, 204; rotation, 107 Wavelengths of light, 171 THE END