SIR WILLIAM HERSCHEL 115 



There is a telescopic milky way, which Dr. H. has traced out in 

 the heavens in many sweeps made from the year 1783 to 1789. It 

 takes up a space of more than 60 square degrees of the heavens, and 

 there are thousands of stars scattered over it : among others, four 

 that form a trapezium, and are situated in the well known nebula of 

 Orion, which is included in the above extent. All these stars, as 

 well as the four mentioned, he takes to be entirely unconnected with 

 the nebulosity which involves them in appearance. Among them is 

 also d Orionis, a cloudy star, improperly so called by former astron- 

 omers; but it does not seem to be connected with the milkiness any 

 more than the rest. 



Dr. H. now comes to some other phenomena, that, from their sin- 

 gularity, merit undoubtedly a very full discussion. Among the 

 reasons which induced us to embrace the opinion that all very faint 

 milky nebulosity ought to be ascribed to an assemblage of stars is, 

 that we could not easily assign any other cause of sufficient im- 

 portance for such luminous appearances, to reach us at the immense 

 distance we must suppose ourselves to be from them. But if an 

 argument of considerable force should now be brought forward, to 

 show the existence of luminous matter, in a state of modification 

 very different from the construction of a sun or star, all objections, 

 drawn from our incapacity of accounting for new phenomena on old 

 principles, he thinks, will lose their validity. 



Hitherto Dr. H. has been showing, by various instances in objects 

 whose places are given, in what manner we may form ideas of con- 

 nection, and its contrary, by an attentive inspection of them only ; he 

 now relates a series of observations, with remarks on them as they are 

 delivered, from which he afterwards draws a few simple conclusions, 

 that seem to be of considerable importance. 



October 16, 1784. A star of about the ninth magnitude, sur- 

 rounded by a milky nebulosity, or chevelure, of about 3' in diameter. 

 The nebulosity is very faint, and a little extended or elliptical, the 

 extent being not far from the meridian, or a little from north pre- 

 ceding to south following. The chevelure involves a small star, 

 which is about 1^4' north of the cloudy star; other stars of equal 

 magnitude are perfectly free from this appearance. (R.A. 5h 57m 

 4s. P.D. 96° 22^). His present judgment concerning this remark- 

 able object is, that the nebulosity belongs to the star which is situated 



