meridian, or between the eye of an observer and an apparently
larger object, as that of Mercury or Venus over the disk of the
sun, and the satellites of Jupiter over its disk; of a star, 65.
ULTIMATE FORCE, the, 249.
URANUS, elements of, 173; moons of, retrograde, 174; perturbed by
VARIABLE STARS, 220.
VERNIER, a scale to measure very minute distances.
VERTICAL CIRCLE, one that passes through the zenith and nadir of
the celestial sphere. The prime vertical circle passes through the
east and west points of the horizon.
VULCAN, discovery of, 137.
WORLDS, THE, AND THE WORD, teach the same truth, 231-245.
YEAR, the, length of, on any planet, is determined by the periodic
ZENITH, the point in the celestial sphere directly overhead.
ZODIAC, a belt 18 deg. wide encircling the heavens, the ecliptic being
the middle. In this belt the larger planets always appear. In
the older astronomy it was divided into twelve parts of 30 deg.
each, called signs of the zodiac.
ZODIACAL LIGHT, 80.
Detach any of the following maps, appropriate to the time of year, hold it between you and a lantern out-of-doors, and you have an exact miniature of the sky. Or, better, cut squares of suitable sizes from the four sides of a box; put a map over each aperture; provide for ventilation, and turn the box over a lamp or candle out-of-doors. Use an opera glass to find the smaller stars, if one is accessible.
[Illustration: Circumpolar Constellations. Always visible. In this position.—January 20th, at 10 o’clock; February 4th, at 9 o’clock; and February 19th, at 8 o’clock.]
[Illustration: Algol is on the Meridian, 51 deg. South of Pole.—At 10 o’clock, December 7th; 9 o’clock, December 22d; 8 o’clock, January 5th.]
[Illustration: Capella (45 deg. from Pole) and Rigel (100 deg.) are on the Meridian at 8 o’clock February 7th, 9 o’clock January 22d, and at 10 o’clock January 7th.]
[Illustration: Regulus comes on the Meridian, 79 deg. south from the Pole, at 10 o’clock March 23d, 9 o’clock April 8th, and at 8 o’clock April 23d.]
[Illustration: Arcturus comes to the Meridian, 70 deg. from the Pole, at 10 o’clock May 25th, 9 o’clock June 9th, and at 8 o’clock June 25th.]
[Illustration: Altair comes to the Meridian, 82 deg. from the Pole, at 10 o’clock P.M. August 18th, at 9 o’clock September 2d, and at 8 o’clock September 18th.]
[Illustration: Fomalhaut comes to the Meridian, only 17 deg. from the horizon, at 8 o’clock November 4th.]