8;
distance from Sun of, 558;
ellipse of, 313;
first taken for a comet, 304;
Flamsteed's observations of, 311, 312;
formerly regarded as a star, 311, 312;
investigations to discover a planet outside the orbit, 323-324;
irregular motion of, 314, 323;
Lemonnier's observations of, 312;
Leonids and, 386;
Mayer's observations of, 312;
moment of momentum of, 554;
orbit of, 117, 310;
periodic time of, 558;
period of revolution of, 312;
rotation of, 308;
satellites of, 559;
satellites, discovery by Herschel, 308;
satellites, movement nearly circular, 309;
satellites, periodical movements, 309;
satellites, plane of orbits, 309, 310;
size of compared with the Earth, 308;
and with other planets, 119;
subject to another attraction besides the Sun, 314

Ursa major (_see_ Great Bear)

V

Variable Stars, 429

Vega, 414, 423, 424, 479;
Struve's measurement of, 442

Velocity, of light, 261, 262, 265;
of light, laws dependent upon, 511;
of planets, 140-143, 146, 237;
of stars, values of, 483-4

Venus, ancient study of, 6;
aspects of, 171;
atmosphere of, 189;
brilliancy of, 168;
density of, 558;
diameter of, 191, 558;
distance of, from the Sun, 191, 558;
habitability of, 173;
movement of, 168;
neighbour to the Earth, 109;
orbit of, 114, 135;
orbit form of, 139, 191;
periodic time of, 558;
a planet or "wanderer," 111;
rotation of, 191;
shape of, 169;
size of, compared with other planets, 116, 169;
surface of, 171;
transit of, 152, 176-190;
transit, importance of, 173;
transit predicted by Kepler, 163;
velocity and periodic time of, 142, 143, 191;
view of the ancients about, 157

Vesta, 233, 238

Victoria, 242

Vienna telescope, 14-16

Virgo, 423

Vogel and Algol, 485;
and Spica, 486, 487;
and the spectra of the stars, 479, 483

Volcanic origin of meteorites, 400;
outbreaks on the Earth, 197

Von Asten and Encke's comet, 349, 350;
and the distance of the Sun, 351;
and the weight of Mercury, 166

Vortex rings, 469

Vulcan, 152, 153;
and the Sun, 3

W

Wargentin, 90

Watson, Professor, and Mercury, 154

Watson, Sir William, friendship with Herschel, 302

Wave-lengths, 60

Weather, not affected by the Moon, 82

Wilson, Mr. W.E., and the nebula in Orion, 469

Witt, Herr G., and Eros, 236

Wold Cottage meteorite, the, 392

Wright, Thomas, and the Milky Way, 474