ASTRONOMY WITH AJV OPERA-GLASS. 



197 



ing as occupying that part of the heavens toward which the proper 

 motion of the sun in space is bearing the earth and its fellow planets, 

 at the rate, probably, of not less than 160,000,000 miles in a year a 

 stupendous voyage through space, of whose destination we are as 

 ignorant as the crew of a ship sailing under sealed orders, and, like 

 whom, we must depend upon such inferences as we can draw from 

 courses and distances, for no other information comes to us from the 

 flag-shin of our squadron. 



Hercules, Lyra, and the Northern Crown. 



In the accompanying map we have represented the beautiful con- 

 stellations Lyra and the Northern Crown, lying on either side of Her- 

 cules. The reader should note that the point overhead in this map is 

 not far from the star Eta (//) in Hercules. The bottom of the map is 

 toward the south, the right-hand side is west, and the left-hand side 

 east. It is important to keep these directions in mind, in comparing 

 the map with the sky. For instance, the observer must not expect to 

 look into the south and see Hercules half-way up the sky, with Lyra a 

 little east of it ; he must look for Hercules nearly overhead, and Lyra 

 a little east of the zenith. The same precautions are not necessary in 

 using the maps of Scorpio, Sagittarius, and Ophiuchus, because those 

 constellations are nearer the horizon, and so the observer does not have 

 to imagine the map as being suspended over his head. 



