THE NEBULA IN ANDROMEDA. 83 



lies in a great circle passing near the nucleus. In some places, not 

 in the immediate vicinity of the nucleus, its resemblance to the 

 milky way, as it appears to the naked eye, both as to its structure 

 and in the number and disposition of the stars in it, is such, that 

 the comparison conveys a tolerably correct idea of its appearance 

 when seen under the most favorable circumstances. 



The justice of this comparison received some additional confir- 

 mation on counting the number of stars visible in different fields of 

 view. It was thought that, in the richest regions, two hundred to 

 a single field was not an extravagant estimate. 



The power employed being one hundred and three, having a 

 field of view of twenty minutes, the apparent field subtended an 

 angle of about thirty-four degrees. The portion of the milky way 

 included in a circle of the same dimensions described about a 

 Cygni contains about two hundred and ten stars, visible \vithout 

 telescopic aid. It should be noticed that the presence of these 

 stars is no safe indication of resolution, since there is equal reason 

 for supposing that we are viewing the nebula through a dense 

 stellar stratum, which would produce the same impression on the 

 eye. 



The nebula h 51 is involved in the light of the great nebula. 

 h 44 appears, under high powers, to be a coarse cluster of stars, 

 the direction of the axis teing determined apparently by three 

 somewhat brighter than their companions ; there is little doubt of a 

 connection with the great nebula, by a continuation of the axis of 

 A 44 in the south-following direction. 



h 45, which is registered as " a very large space filled with 

 nebulous matter," is far within the limits of the great nebula. No. 

 7 of the catalogue of " Extensive Diffused Nebulosities," published 

 by Sir William Herschel in the Philosophical Transactions for 

 1811, is also a part of the great nebula. 



