HOW TO OBSERVE THE HEAVENS. 



The constellation of the Great Bear being in the quarter of the 

 heavens opposite to that in which the sun is found in the begin- 

 ning of September, it will be seen on the meridian not far south 

 of the zenith at that season in these latitudes, at midnight. 



It will, on the contrary, be on the meridian a little above the 

 horizon at midnight, in the beginning of March. The most 

 favourable times, therefore, for observations upon it, are the months 

 of summer and autumn. 



20. A circle described round the north celestial pole, including 

 within it a certain extent of the heavens is called the Arctic circle, 

 from the Greek word "Ap/cros, " arktos," signifying a bear, that 

 being, as it were, the region of the bears. 



21. To extend the method of pointers to the discovery of the 

 position of other constellations, let us suppose a line carried from 

 the star 5 of Ursa major to the pole star, and continued beyond 

 the pole star to an equal distance ; this line will then arrive at a 

 well-known constellation called Cassiopeia's chair. This constel- 

 lation consists of several stars, six of which being the most con- 

 spicuous are shown in fig. 4. Four of these o, p, K, and 7, formed 

 the legs and seat, and the two others 8 and e the back. 



Fig. 4. 



If the line drawn from a of Ursa major through the pole star 

 be continued beyond the latter nearly in a direct line, it will 

 arrive at a constellation called Pegasus, which will be easily 

 recognised by four brilliant stars forming a quadrangle very 

 similar to that already described in the constellation of Ursa 

 major. This quadrangle with its position relatively to the pole 

 star, and the line proceeding through that star from the pointers 

 is shown in fig. 5. 



22. Of these four stars, three only properly belong to the con- 

 stellation called Pegasus ; these three being 0, a, and .7, forming 

 the upper right hand corner of the quadrangle. The fourth star, 

 marked also , belongs to an adjacent constellation called Andro- 

 156 



