Capricorn, tropic of, 61. Capricornus, or the Goat, 350. Cassiopeia (constellation), 332. new star in, 362. Castor, star in Gemini, 340, 370. Caucasus, a lunar range, 124. Centaurus, star-cluster in, 355. Cepheus (constellation), 334. nebula in, 387. Ceres, the planet, 241. Cetus, or the Whale, 346. variable star in, 359. Charles's Wain, 330. Circles, great, 4. diurnal, 8. hour, 16. small, 4. vertical, 12. Clock, astronomical, 18. time, 78. Coma Berenices, or Berenice's Hair, 334. Comet, Biela's, 293. and earth, collision of, 316. Coggia's, 297. Donati's, 296. Encke's, 293. Halley's, 291. of 1680, 290. of 1811, 290. of 1843, 295. of 1861, 297. of June, 1881, 300. Comets, appearance of, 274. and meteors, 313. bright, 274. chemical constitution of, 318. development of, 277. number of, 288. orbits of, 282. origin of, 287. periodic, 286. physical constitution of, 314. tails of, 279. telescopic, 275, 281. visibility of, 281. Conic sections, 48. Conjunction, 91. inferior, 130. superior, 130, 136. Constellations, 325. zodiacal, 32. Copernican system, the, 44, 53. Copernicus, a lunar crater, 120, 129. Corona Borealis, or the Northern Crown, 336. Corona Borealis, new star in, 363. Corvus, or the Crow, 339. Crystalline spheres, 41. Cycles and epicycles, 42. Cygnus, or the Swan, 338. D. Day and night, 57. civil, 77. lunar, 108. sidereal, 74. solar, 74. Declination, 16. Deimos, satellite of Mars, 239. Delphinus, or the Dolphin, 338. Deneb, star in Cygnus, 338, 370. Dione, satellite of Saturn, 259. Dipper, the Great, 330, 366, 369, 370. the Little, 331. the Milk, 347. Dissociation, 163. Dominical Letter, the, 81. Draco, or the Dragon, 331. E. Earth, density of, 85. flattened at poles, 55. form of, 53. in space, 56. seen from moon, 109. size of, 55. weight of, 83. Eccentric, the 43. Eccentricity, 46. Eclipses, 210. annular, 219. lunar, 210, 214. solar, 216. Ecliptic, the, 27. obliquity of, 28. Ellipse, the, 45, 49. Elongation, of planet, 130. Enceladus, moon of Saturn, 259. Epicycles, 42. Epicycloid, 107. Epsilon Lyræ, a double star, 356. Equator, the celestial, 7. Equinoctial, the, 7. colure, 16. elevation of, 9. Equinox, autumnal, 29. vernal, 16, 29. Equinoxes, precession of, 31, 85. Eta Argus, a variable star, 360, 383. Europa, moon of Jupiter, 250. F. Faculæ, solar, 177. Fomalhaut, star in Southern Fish, 350. Fraunhofer's lines, 164, 371. G. Galaxy, the, 326. Ganymede, moon of Jupiter, 250. Gemini, or the Twins, 340. Georgium Sidus, 271. H. Hercules (constellation), 336. cluster in, 353. orbit of double star in, 357. solar system moving towards, 367. Herschel, the planet (see Uranus). Herschel's hypothesis, 392, 396. Horizon, the, 5.