Hyades, the, 342, 350. Hydra, or the Water-Snake, 340. Hyperbola, the, 49. Hyperion, moon of Saturn, 259. I. Io, moon of Jupiter, 250. Irradiation, 90, 113. J. Japetus, moon of Saturn, 259. Job's Coffin (asterism), 338. Juno, the planet, 241. Jupiter, apparent size of, 245. distance of, 245. great red spot of, 249. orbit of, 244. periods of, 246. physical constitution of, 246. rotation of, 248. satellites of, 250. eclipses of, 252. transits of, 254. volume of, 245. without satellites, 255. K. Kant's hypothesis, 391. Kepler, a lunar crater, 129. Kepler's system, 44. laws, 46. star, 362. Kirchhoff's map of spectrum, 164. L. Laplace's hypothesis, 392. Latitude, celestial, 30. Leap year, 81. Leo, or the Lion, 334. Leonids (meteors), 312. Libra, or the Balances, 347. Libration, 102. Longitude, celestial, 30. Lyra, or the Lyre, 338. double star in, 356. M. Magellanic clouds, the, 389. Magnetic storms, 190. Magnetism and sun-spots, 190. Mars, apparent size of, 236. brilliancy of, 237. distance of, 235. orbit of, 235. periods of, 237. rotation of, 239. satellites of, 239. volume of, 236. Mercury, apparent size of, 226. atmosphere of, 228. distance of, 225. elongation of, 227. orbit of, 225. periods of, 227. volume of, 226. Meridian, the, 12. Meridian circle, 17. Meridians, celestial, 31. Meteoric iron, 305, 307. showers, 310. stones, 305. Meteors, 300. August, 311. light of, 309. November, 312. sporadic, 310. Meteoroids, 308. Micrometers, 20, 153. Milky-Way, the, 326. Mimas, moon of Saturn, 259. Mira, a variable star, 359. Moon, apparent size of, 87, 89. aspects of, 91. atmosphere of, 109. chasms in, 123. craters in, 119. day of, 108. distance of, 86. eclipses of, 210. form of orbit, 97. harvest, 101. hunter's, 102. inclination of orbit, 97. kept in her path by gravity, 51. librations of, 102. mass of, 90. meridian altitude of, 98. mountains of, 116. orbital motion of, 91. phases of, 93. real size of, 88. rising of, 99. rotation of, 102. sidereal period of, 92. surface of, 115. synodical period of, 92. terminator of, 115. wet and dry, 98. N. Nadir, the, 6. Neap-tides, 72. Nebula, in Andromeda, 376. crab, 376. dumb-bell, 383. in Argus, 383. in Canes Venatici, 384. in Cepheus, 387. in Orion, 378. in the Triangle, 387. in Ursa Major, 386. Nebulæ, 281, 330, 373. annular, 373. circular, 373. condensation of, 385. double, 375. elliptical, 373. irregular, 376. multiple, 375. spiral, 373, 384. Nebular hypothesis, the, 391. Neptune, discovery of, 271. orbit of, 271. satellite of, 274. New style, 80. Newcomb's theory of the stellar universe, 398. Newton's system, 48. Nodes, 97. Nubecula, Major, 389. Minor, 389.