Part 47

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.

Nutation, 34.

Olbers's hypothesis, 241.

Old style, 80.

Ophiuchus (constellation), 347. new star in, 362.

Opposition, 91, 136.

Orion, 341. nebula in, 378. the trapezium of, 356.

Pallas, the planet, 241.

Parabola, the, 49.

Parallax, 37.

Pegasus (constellation), 343, 346. triple star in, 356.

Perigee, 44.

Perihelion, 47.

Perseids (meteors), 311.

Perseus (constellation), 346. cluster in, 353.

Phobos, satellite of Mars, 239.

Pico, a lunar mountain, 127.

Pisces, or the Fishes, 350.

Piscis Australis, or the Southern Fish, 350.