34 o THE POPULAR SCIENCE MONTHLY. 



of the geometrical arrangement of the former. So with the chain 

 of telescopic stars described above as winding around the bright 

 stars in the Belt the nebular forms account for the configura- 

 tion of the stars. 



In the cut of Orion's Belt, above, an attempt has been made to 

 represent the appearance of the assemblage of small stars around 

 Epsilon, the center star of the Belt. All the stars there shown 

 can not be seen with an ordinary opera-glass, but a strong field- 

 glass will reveal them and many more besides. In fact, with a 

 powerful glass the complication of curving star -lines becomes 

 rather confusing to one attempting to draw them, and the cut 

 must be regarded rather as an "impressionist" picture than as 

 one showing every star accurately in its place and of precisely 

 the right magnitude. Still, it will be found an approximately cor- 

 rect representation. The reader should bear in mind the fact that 

 the star Epsilon, the center of this remarkable sidereal array, has 

 long been known to be surrounded by a strong nebulosity, and 

 that in the photograph referred to this spot appears as one of the 

 principal foci of the great spiral nebula. These considerations 

 naturally lead to the conclusion (which has also been reached 

 upon other grounds so far as the larger stars are concerned) that 

 Epsilon and the other leading stars of Orion, with the exception 

 of Betelgeuse, which lies beyond the boundaries of the nebula, 

 are at practically the same distance from us as the small stars 

 surrounding them, all being members of one system. 



There are many such star-streams to be found in the sky 

 where as yet no related nebulae have been discovered. But one 

 can hardly doubt, in view of the evidence which the photographs 

 we have referred to furnish, that the forms of the streams are 

 derived from the pre-existing forms of the parent nebulae. In 

 many cases, of course, the process of nebular condensation has 

 been finished, and we can never expect to discover any evidence 

 of the nebula having once existed beyond the peculiar configura- 

 tion of the stars to which it gave birth. In other cases, as in this 

 of Orion, photography may yet reveal to us the existence of faint 

 nebulous spirals still connected with the star-groups. Prof. 

 Holden's discovery of a starry ring connected with the celebrated 

 ring nebula in Lyra is in direct accord with the revelations of 

 photography in this respect. Another interesting example is 

 furnished by Mr. W. F. Denning's discovery last September of a 

 small nebula which is completely encircled by a ring of stars. It 

 is impossible, when looking at Mr. Denning's sketch of this curi- 

 ous object in The Observatory, to think that the stars and the 

 nebula there shown do not belong to a single system. 



Among the most striking examples of curved or spiral stellar 

 arrangement are the circlet of small stars surrounding Delta 



