It may be added that only bright stars, and stars easily seen, are included in the charts, and there will be no danger of mistaking any of these stars for a planet, if the observer first carefully learns to recognize their configurations. Neither Mars, Jupiter, nor Saturn ever appears as faint as any of the stars, except those of the first magnitude, included in the charts. Uranus and Neptune being invisible to the naked eye--Uranus can occasionally be just glimpsed by a keen eye--are too faint to be found without the aid of more effective appliances.
Agassiz, Alexander, on deep-sea animals, 63.
Asteroids, the, 16, 129. brightness of, 130. imaginary adventures on, 146. life on, 144. number of, known, 129. orbits of, 132. origin of, 138, 143. size of, 129.
Bailey, Solon I., on oppositions of Eros, 134.
Barnard, E.E., discovers fifth satellite of Jupiter, 181. measures asteroids, 129. on Saturn's rings, 205.
Darwin, George H., on Jupiter and Saturn, 206. on origin of moon, 235. theory of tidal friction, 32.
Denning, W.F., description of Jupiter, 175.
Dewar, James, discovers free hydrogen in air, 232.
Douglass, A.E., sees Mars's canals, 92. sees clouds in Mars, 119.
Earth and moon's orbit, 217. birth of moon from, 236. change of distance from sun, 27. less advanced than Mars, 89. older than Venus, 58. seen from Mercury, 41. seen from Venus, 69-71, 75. seen from moon, 214.
Earth, similarity to Venus, 46. supposed signals to and from Mars, 110.
Elger, T.G., on cracks in moon, 227. on Tycho's rays, 246.
Flammarion, C., observes Venus's atmosphere, 56. on plurality of worlds, 8.
Forbes, Prof. George, on ultra-Neptunian planet, 210.
Gravity, as affecting life on planets, 20, 46.
Holden, E.S., on photograph of lunar crater, 242.
Interplanetary communication, 1, 3, 72, 110, 112.
Jupiter, cloudy aspect of, 165. density of, 162. distance of, 161. equatorial belts on, 165. future of, 180. gravity on, 162. great red spot on, 169. markings outside the belts, 168. and the nebular theory, 178. once a companion star, 179. polar compression of, 161. possibly yet incandescent, 177. question of a denser core, 176. resemblance of, to sun, 174. rotation of, 161, 173. satellites of, 166, 181. seen from satellites, 182. size of, 160. solar light and heat on, 182. south belt of, 172. surface conditions of, 163. theories about the red spot, 170. trade-winds and the belts of, 167. various rates of rotation of, 173. visibility of rotation of, 166.