75 o THE POPULAR SCIENCE MONTHLY. 



constellation Cancer. The two stars on either side of it are called the 

 Aselli, or the Ass's Colts, and the imagination of the ancients pictured 

 them feeding from their silver manger. Turn your glass upon the 

 Manger and you will see that it consists of a crowd of little stars, so 

 small and numerous that you will probably not undertake to count 

 them, unless you are using a large field-glass. Galileo has left a de- 

 lightful description of his surprise and gratification when he aimed his 

 telescope at this curious cluster and discovered what it really was. 

 Using his best instrument, he was able to count thirty-six stars in the ] 

 Manger. The Manger was a famous weather-sign in olden times, and 

 Aratus, in his " Diosemia," advises his readers to — 



"... watch the Manger : like a little mist 

 Far north in Cancer's territory it floats. 

 Its confines are two faintly glimmering stars ; 

 These are two asses that a manger parts, 

 Which suddenly, when all the sky is clear, 

 Sometimes quite vanishes, and the two stars 

 Seem to have closer moved their sundered orbs. 

 No feeble tempest then will soak the leas; 

 A murky manger with both stars 

 Shining unaltered is a sign of rain." 



Like other old weather-saws, there is probably a gleam of sense in 

 this, for it is only when the atmosphere is perfectly transparent that 

 the Manger can be clearly seen ; when the air is thick with mist, the 

 harbinger of coming storm, it fades from sight. 



Below the Manger, a little way toward the south, your eye will be 

 caught by a group of four or five stars of about the same brightness 

 as the Aselli. This marks the head of Hydra, and the glass will show 

 a striking and beautiful geometrical arrangement of the stars compos- 

 ing it. Hydra is a very long constellation, and trending southward 

 and eastward from the head it passes underneath Leo, and, sweeping 

 pretty close down to the horizon, winds away under Corvus, the tail 

 reaching to the eastern horizon. Its stars are all faint, except Alphard, 

 or the Hydra's Heart, a second-magnitude star, remarkable for its lonely 

 situation, southwest of Regulus. A line from Gamma Leonis through 

 Regulus points it out. It is worth looking at with the glass on account 

 of its rich orange-tint. 



Coming back again to the Manger as a starting-point, look well 

 up to the north and west, and at a distance somewhat less than that 

 between Regulus and the Manger you will see a pair of first-magni- 

 tude 'stars, which you will hardly need to be informed are the cele- 

 brated Twins, from which the constellation Gemini takes its name. 

 The star marked a in the map is Castor, and the star marked /3 is Pol- 

 lux. No classical reader needs to be reminded of the romantic origin 

 of these names. 



A sharp contrast in the color of Castor and Pollux comes out as 



