1,167,000 miles 16 16 32 11

THE SATELLITES OF SATURN.

Mean Distance from Periodic Time.
Name. Centre of Saturn. days. hrs. mins. secs.

Mimas 115,000 miles 0 22 37 6
Enceladus 148,000 miles 1 8 53 7
Tethys 183,000 miles 1 21 18 26
Dione 235,000 miles 2 17 41 9
Rhea 329,000 miles 4 12 25 12
Titan 760,000 miles 15 22 41 27
Hyperion 921,000 miles 21 6 38 31
Iapetus 2,215,000 miles 79 7 56 40

THE SATELLITES OF URANUS.

Mean Distance from Periodic Time.
Name. Centre of Uranus. days. hrs. mins. secs.

Ariel 119,000 miles 2 12 29 21
Umbriel 166,000 miles 4 3 27 37
Titania 272,000 miles 8 16 56 30
Oberon 364,000 miles 13 11 7 6

THE SATELLITE OF NEPTUNE.

Mean Distance from Periodic Time.
Name. Centre of Neptune. days. hrs. mins. secs.

Satellite 220,000 miles 5 21 2 44

INDEX.

A

Aberration of light, 503-512;
and the apparent movements of stars, 504, 507;
Bradley's discoveries, 503;
causes, 507-511;
circles of stars, 505-507;
dependent upon the velocity of light, 511;
effect on Draco, 505;
telescopic investigation, 510

Achromatic combination of glasses, 11

Adams, Professor J.C., and the discovery of Neptune, 324-327, 330-332;
and the Ellipse of the Leonids, 386

Aerolite, the Chaco, 398;
the Orgueil, 399

Airy, Sir George, 325

Alban Mount Meteorites, the, 393

Alcor, 438

Aldebaran, 209, 418, 419;
spectrum of, 480;
value of velocity of, 484

Algol, 485, 487

Almagest, the, 7

Alphonsus, 92

Alps, the great valley of the (lunar), 88

Altair, 424

Aluminium in the Sun, 50

Ancients, astronomy of the, 2-7

Andrews, Professor, and basaltic formation at Giant's Causeway, 407

Andromeda, 414;
nebula in, 469, 489

Andromedes, The, shooting star shower, and Biela's comet, 390

Antares, 423

Apennines (lunar), 83

Aphelion, 163

Aquarius, 215, 413

Aquila, or the Eagle, 424

Arago, 326

Archimedes, 88

Arcturus, 358, 480;
value of velocity of, 484

Argelander's Catalogue of Stars, 4