566 



SCIENCE 



[N. S. Vol. XXV. No. 641 



clusters are known in the whole sky. Less 

 than 600 of these are irregular; nearly all 

 are in or near the Milky Way, of which 

 they form an intimate part, as has long 

 been known. More than 100 resolvable 

 globular clusters are known, the distribu- 

 tion of which bears no relation whatever 

 to the Milky Way, although a rich group 

 of such clusters is found in the Milky Way. 

 This appears to be an accident, however, 

 since they do not seek the lines of greatest 

 luminosity. This peculiar distribution of 

 the globular clusters does not seem to have 

 been pointed out before. Discovery of 

 irregular clusters has been practically ex- 

 hausted by small telescopes, since powerful 

 photographic instruments reveal few new 

 ones. It is probable, however, that the 

 number of known globular clusters will be 

 considerably increased among the so-called 

 nebulous stars. 



About 12,000 nebulae are now known. 

 The whole number in the sky, however, is 

 several times, perhaps many times, greater. 

 The white nebulae are distributed in cloud- 

 like groups over the sky, avoiding, in gen- 

 eral, the Milky Way. The gaseous nebulae 

 occur probably over the whole sky, perhaps 

 in greater numbers in the Milky Way 

 where the most striking objects of this class 

 are found. The gaseous nebulfe are prob- 

 ably few in number compared with the 

 white nebulffi. 



The majority of all nebulge are spiral, 

 but there are large numbers of nebulous 

 stars, many of which may be faint globu- 

 lar clusters. The relation between spiral 

 nebulae and globular clusters may prove to 

 be more intimate than is now apparent. 



The Nebulous Regions of the 3Iilky Way: 



E. E. Barnard. 



This paper deals with some peculiarities 

 of the nebulosities in the Milky Way. 

 Though in some cases there seems to be 

 every evidence that the stars and nebulosi- 



ties are freely mixed together, still pecul- 

 iarities of distribution, etc., show that 

 with few exceptions (such as p Ophiuchi) 

 the nebulosity does not indicate any tend- 

 ency to condense about the stars. This is 

 especially striking in the case of the great 

 North America Nebula (so named by Dr. 

 Max Wolf), where to all appearances the 

 stars seem to exist in a vast bed of nebulous 

 matter with no condensation about them 

 individually. In this particular case the 

 identity of the details of the nebula and 

 the groupings of the stars seem to be 

 conclusive proof that the nebula and the 

 stars, apparently in it, really occupy the 

 same part of space. Even in the case of 

 that remarkable combination of nebulosity 

 and stars, M 8, the stars seem freely mixed 

 with the nebulosity, but in no case to be 

 centers of condensation. Contrary to this 

 condition, the great nebula of p Ophiuchi 

 has condensation about the principal stars 

 in that region, including o- Scorpii. 



A photograph shows the singular nebu- 

 losities about y Cygni, where a profusion of 

 curved sheets and wreaths of nebulous mat- 

 ter cover a large part of the sky about the 

 star and extend as far south as x Cygni. 

 A photograph of the nebula about v Scorpii 

 seems to show quite distinctly an obscura- 

 tion of the light of the stars in that region. 

 Where this remarkable object veils the sky, 

 the stars seem to have decreased in magni- 

 tude. It gives the impression that the 

 brighter stars in this region are dimmed 

 and the fainter ones blotted out, as if pro- 

 duced by a thin obscuring veil of nebulosity 

 this side of the small stars. This pecu- 

 liarity is very strikingly brought out by 

 the photograph. 



In A. N. No. 3,111, Bd. 130, the writer 

 has given an account, with a sket^^h, of a 

 group of small nebulous stars 



{I860 (i=18"2"' 



S = 23°52'±), 



which lies about 1^° following M 8. When 



