,94 THE POPULAR SCIENCE MONTHLY. 



observations such as these. Everybody knows how the moonlight 

 blots out the smaller stars. A slight haziness, or smoke, in the air 

 produces a similar effect. It is as important to the observer with an 

 opera-glass to have a transparent atmosphere as it is to one who would 

 use a telescope ; but, fortunately, the work of the former is not so 

 much interfered with by currents of air. Always avoid the neighbor- 

 hood of any bright light. Electric lights in particular are an abomi- 

 nation to star-gazers. 



The cloud of stars we have just been looking at is in a very rich 

 region of the Milky -Way, in the little modern constellation called 

 "Sobieski's Shield," which we have not placed upon our map. Sweep- 

 ing slowly upward from 24 M. a little way with the field-glass, we will 

 pass in succession over three nebulous-looking spots. The second of 

 these, counting upward, is the famous Horseshoe nebula. Its won- 

 ders are beyond the reach of our instrument, but its place may be 

 recognized. Look carefully all around this region, and you will per- 

 ceive that the old gods, who traveled this road (the Milky -Way was 

 sometimes called the pathway of the gods), trod upon golden sands. 

 Off a little way to the east you will find the rich cluster called 25 M. 

 But do not imagine the thousands of stars that your opera-glass or 

 field-glass reveals comprise all the riches of this Golconda of the 

 heavens. You might ply the powers of the greatest telescope in a 

 vain attempt to exhaust its wealth. As a hint of the wonders that 

 lie hidden here, let me quote Father Secchi's description of a starry 

 spot in this same neighborhood, viewed with the great telescope at 

 Rome. After telling of " beds of stars superposed upon one another," 

 and of the wonderful geometrical arrangement of the larger stars 

 visible in the field, he adds : 



"The greater number are arranged in spiral arcs, in which one can 

 count as many as ten or twelve stars of the ninth to the tenth mag- 

 nitude following one another in a curve, like beads upon a string. 

 Sometimes they form rays which seem to diverge from a common 

 focus, and, what is very singular, one usually finds, either at the cen- 

 ter of the rays, or at the beginning of the curve, a more brilliant star 

 of a red color, which seems to lead the march. It is impossible to be- 

 lieve that such an arrangement can be accidental." 



The reader will recall the somewhat similar description that Ad- 

 miral Smyth and Mr. Webb have given of a star-cluster in Gemini 

 (see "Popular Science Monthly" for April). 



The groups of stars forming the eastern half of the constellation 

 of Sagittarius are worth sweeping over with the glass, as a number 

 of pretty pairs may be found there. 



Next let us pass to the double constellation adjoining Scorpio and 

 Sagittarius on the north Ophiuchus and the Serpent. These constel- 

 lations, as our map shows, are curiously intermixed. The imagination 

 of the old star-gazers, who named them, saw here the figure of a giant 



