90 ASTRONOMY. 
12. Besides the division of stars according to their apparent size, they are 
classified as single, double, and multiple stars, variable and temporary stars, 
and nebulous stars. These will all be referred to hereafter. Groups of. 
stars which are visible, partly to the naked eye, partly by means of the 
telescope, are called constellations ; while those in which, even with the aid 
of the most powerful telescope, the individual stars cannot be made out, the 
whole appearing as a light nebulous cloud, are called nebule. Finally, that. 
belt of light formed by innumerable stars, and encompassing the whole 
heavens, varying in breadth and concentration, exhibiting sometimes one 
branch, and sometimes two, is called the milky way. This passes through 
the constellations (pls. 12, 13) Cassiopeia, Perseus, Orion, Gemini, Argo, 
Centaurus, Ara, Scorpio, Sagittarius, Ophiuchus, Aquila, Cygnus, and 
Cepheus. Its two branches unite in Ara and Cygnus. 
THE CONSTELLATIONS. 
13. For the sake of assisting the memory in recollecting the general distri- 
bution and relations of the stars in the sky, they have been divided into 
constellations. Those of the northern hemisphere are represented in pl. 12, 
those of the southern in pl. 13. These constellations are groups of fixed 
stars, whose outlines have been supposed to represent figures of men, animals, 
and other objects, and to which corresponding names have been given. 
With the arrangement of new constellations, it becomes necessary to have 
new names, which may either be derived from the animal kingdom, as done 
by the ancients, e. g. the Giraffe and the Lizard, or names may be selected 
commemorating important discoveries and inventions in the arts and 
sciences, e.g. the compass, the air pump, and the pendulum clock. 
The names of the separate constellations, as given by Hipparchus, are 
the following :— 
a. The Twelve Constellations of the Zodiac. 
v Aries, (Ram,) Widder. 
¥ Taurus, (Bull,) Stier. 
m Gemini, (T wins,) . Lwillinge. 
c; Cancer, (Crab,) Krebs. 
a Leo, (Lion,) Lowe. 
m Virgo, (Virgin,) Jungfrau. 
-. Libra, (Balance,) Wage. 
m Scorpio, (Scorpion,) Skorpion. 
+ Sagittarius, (Archer,) Schiitze. 
vs Capricornus, (Goat,) Steinbock. 
sr Aquarius, (Water Bearer,) Wassermann. 
x Pisces, (The Fish,) Fische. 
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