§ 279. _Henderson’s_ parallax of α _Centauri_ and _Struve’s_ of _Vega_: later parallax determinations 362 § 280. Star catalogues: the photographic chart 362 §§ 281-4. The distance of the sun: transits of Venus: observations of Mars and of the minor planets in opposition: _diurnal method_: gravitational methods, lunar and planetary: methods based on the velocity of light: summary of results 363 § 285. Variation in latitude: rigidity of the earth 367 § 286. =Gravitational Astronomy.= Lunar theory: _Damoiseau_, _Poisson_, _Pontécoulant_, _Lubbock_, _Hansen_, _Delaunay_, Professor _Newcomb_, _Adams_, Dr. _Hill_ 367 § 287. Secular acceleration of the moon’s mean motion: Adams’s correction of Laplace: Delaunay’s explanation by means of _tidal friction_ 369 § 288. Planetary theory: _Leverrier_, _Gyldén_, M. _Poincaré_ 370 § 289. The discovery of Neptune by Leverrier and Dr. _Galle_: Adams’s work 371 § 290. Lunar and planetary tables: outstanding discrepancies between theory and observation 372 § 291. Cometary orbits: return of Halley’s comet in 1835: Encke’s and other periodic comets 372 § 292. Theory of tides: analysis of tidal observations by Lubbock, _Whewell_, Lord _Kelvin_, and Professor _Darwin_: bodily tides in the earth and its rigidity 373 § 293. The stability of the solar system 374 § 294. =Descriptive Astronomy.= Discovery of the _minor planets_ or _asteroids_: their number, distribution, and size 376 § 295. Discoveries of satellites of Neptune, Saturn, Uranus, Mars, and Jupiter, and of the _crape ring_ of Saturn 380 § 296. The surface of the moon: _rills_: the lunar atmosphere 382 § 297. The surfaces of Mars, Jupiter, and Saturn: the _canals_ on Mars: _Maxwell’s_ theory of Saturn’s rings: the rotation of Mercury and of Venus 383 § 298. The surface of the sun: _Schwabe’s_ discovery of the periodicity of sun-spots: connection between sun-spots and terrestrial magnetism: _Carrington’s_ observations of the motion and distribution of spots: Wilson’s theory of spots 385 §§ 299-300. _Spectrum analysis_: Newton, _Wollaston_, _Fraunhofer_, _Kirchhoff_: the chemistry of the sun 386 § 301. Eclipses of the sun: the _corona_, _chromosphere_, and _prominences_: spectroscopic methods of observation 389