CONSTELLATIONS. ] 



ASTRONOMY. 



959 



animals most useful to them during the spring months. 

 The Crab, walking backwards, is typical of the retreat of 

 the sun from the northern tropics. The fierce Lion re- 

 presents the intensity of summer heat. The Virgin, 

 holding an ear of corn, refers to a girl gleaning. The 

 Balance indicates the equality of day and night at the 

 equinox ; while the Scorpion indicates disease as the in- 

 cident of the season. 



NORTHERN CONSTELLATIONS. The constellations of the 

 northern hemisphere are thirty-five in number, of which 

 twenty were enumerated by Aratus. Of these Ursa Major 

 is the most conspicuous, consisting of three principal 

 stars, forming a triangle in the tail, and four forming a 

 quadrangle oil the body of the Bear. Commencing at 

 the tip of the tail we have Benetuasch, a star of the 

 second magnitude ; Mizar, 7 distant west ; and Alioth, 

 about 44 further off ; 5J from Alioth, at the root of the 

 tail, is Megrez ; south of it Phad, forming the shorter side 

 of a quadrangle. On the opposite side, 8 west of Phad, 

 is Merak ; and 5 north, towards the pole, is Dubhe, the 

 brightest star of the constellation. 



Dubhe and Merak are called the pointers, because a 

 line drawn through them, and carried about 29 in the 

 came direction, passes almost over Polaris (the pole star), 

 which is close to the north polar point in the heavens. 



Una Minor, while it is inferior to the preceding in 

 point of size, is more important from its position indi- 

 cating the north polar point, and its utility as a guide in 

 finding the latitude of places. Like Ursa Major, it con- 

 sists of seven stars ; three of the third magnitude, and 

 four of the fourth. Polaris is the important star of this 

 group. It is between the second and third magnitudes. 

 It is at the tip of the tail of Ursa Minor, and appears 

 stationary, the rest of the constellations appearing to 

 swing round it in the diurnal revolution of the sphere. 

 All the stars appear to revolve round the pole of the 

 ecliptic, owing to the real revolution of the pole of the 

 earth round it ; a revolution, however, which requires 

 the long cycle of 26,000 years, or thereabouts, for its 

 performance. 



BOOTES appears among the stellar groups to be driving 

 on Ursa Major ; hence it has sometimes been called the 

 Bear Driver. Bootes has Arcturus, a star of the first 

 magnitude, long supposed by the ancients to be the 

 nearest star to the earth. 



SOUTHERN CONSTELLATIONS. The constellations of the 

 southern hemisphere are forty-six in number ; the most 

 important being Orion, which constitutes the richest 

 part of the visible heavens ; and when on the meridian 

 (which occurs about 10 p.m., January 1), presents the 

 most magnificent view the starry heavens offer. Orion 

 it visible, in its turn, to all the habitable world, the 

 equinoctial passing through the centre of it. Four 

 principal stars, in the form of a long square or parallelo- 

 gram, form its outline. Betelgeux, of the first magni- 

 tude, is 7J of Bellatrix of the second ; Saiph of the 

 third magnitude, and Rigel of the first, 8i west of 

 Saiph, and 15 of Bellatrix. Canis Major, on the south- 

 east of Orion, contains one star of the first magnitude, 

 four of the second, and two of the third ; the former, 

 Sirius, glowing in our winter hemisphere with a lustre 

 unequalled by any other star in the firmament. Canis 

 Minor, east of Orion, and north of Canis Major, has two 

 brilliant stars Procyon, of the first magnitude, and 

 Gomelza, of the second, about 4 to the south-east. A 

 knowledge of these constellations will enable us to find 

 our path in the heavens. 



When a few particular stars have been recognised, 

 they will serve as starting-points ; and by alignments, or 

 imaginary lines, drawn from them, other stars and 

 groups of stars will be found, and thus a general know- 

 ledge of celestial objects acquired. For this purpose, 

 one of the most conspicuous objects is the constellation 

 of Ursa Major, which never sets in our latitudes. 



The seven stars (shown in Fig. 104) are nearly all of 

 the same magnitude ; a line drawn through ft and a, and 

 produced to a distance equal to that from a to q, will 

 point out Polaris, an object of the 2 '3 magnitude. This 

 star will be easily distinguished, since it is not surrounded 



by any others of the same magnitude. The alignment to 

 find the Pole Star is as follows : A line drawn from 

 S Ursae Majoris, or from < Ursse Majoris through Polaris, 



and produced the 

 same distance as that 

 from 5 Ursa Majoris 

 to Polaris, will reach 

 the centre of Cassio- 

 peia. This remark- 

 able group of stars, 

 which, in these lati- 

 tudes, is circumpolar, 

 is always on the oppo- 

 site side of Polaris to 

 Ursa Major. When 

 Ursa Major is near the 

 zenith, Cassiopeia is 

 near the horizon, and 

 when Ursa Major is 

 on the eastern side, 

 Cassiopeia is on the 

 western side of Po- 

 laris. 



The right lines, 

 which direct a and /3 

 Ursse Majoris to Po- 

 laris, when produced 

 in the same direction, 

 will point out the 

 square of Pegasus, 

 formed of four stars 

 of the second magni- 

 tude, the two upper 

 of this group being 

 respectively Pegaai and a Androinedce. A line drawn 

 from the two latter will pass through and 7 Andro- 

 mcdee, and finally to a Persei, a star of the second mag- 

 nitude nearer the pole. It will be remarked that a 

 Persoi may also be found by drawing a line from &, a, 

 Ursae Majoris through Polaris. 



On the opposite sides of a Persei are situated 7 and S 

 Persei, stars of the fourth and third magnitudes respt o- 

 tively ; a line drawn from a, S Ursas Majoris will meet 

 (after passing through o Persei) Algol, or J3 Persei, a 

 star remarkable for its variability. Producing the arcs 

 7 and S Persei, we find a Arietis. Below these, the con- 

 spicuous cluster of stars, the Pleiades, are situated. If 

 we join Polaris and a Arietes, and produce it beyond the 

 latter, we shall meet with the constellation Orion, which 

 is well known by its remarkable brilliancy and form. 

 Of this group of stars, S, i, and are called the belt ; 

 the remaining four stars of this group form an irregular 

 quadrilateral, o and 7 being the upper, and /3 and S 

 being the lower sides, a and ft Orionis are of the first 

 magnitude, and all the others are of the second magni- 

 tude. 



The most remarkable object in the heavens, Sirius, or 

 a Canis Majoris, is pointed out by producing the belt of 

 Orion on the eastern side. By producing it on the 

 western side, we meet with Aldebaran, or a Tauri, a star 

 of the first magnitude. But this star may also be found 

 by producing the line which connects a Ursae Majoris and 

 a Arietis (Fig. 105). 



Fig. 105. 



The diagonal of 

 the square [c, /3, 7, 

 i, Ursaa Majoris], 

 or S, ft being pro- 

 duced sufficiently, 

 will pass through 

 the bright stars of 

 the constellation 

 Gemini, a and ft 

 or Castor and Pol- 

 lux. A short dis- 

 tance in the same 

 line, between Castor 

 and Sirius, we find 



Procyon, or a Canis Minoris. This may also be found 

 by prolonging the line passing through Polaris and 



