€ 54 j Herschel’s Astronomical Observations 
301, we have an account of twenty-four extended nebulcC, 
gradually a little brighter in the middle ; page 303 there 
are fifty extended nebulae, with an increased brightness to- 
wards the middle; page 304, we have fifty-four extended 
nebulae, with a much greater accumulation of brightness ; 
page 307 there are seven extended nebulae, in which the cen- 
tral increase of brightness approaches towards the formation 
of a nucleus. Page 309, we have twenty-seven extended 
nebulas, in which the central nucleus is already formed; and 
finally, page 311 contains the account of twenty-three ex- 
tended nebulae, where the nebulosity seems to have so far 
subsided into the nucleus, as to leave only two opposite faint 
branches. Who then that has followed up the gradual con- 
densation of an extended nebula till it appeared in the shape 
of a bright nucleus with faint branches, and finds now in the 
center of two such opposite faint branches, instead of a con- 
densed nucleus, a star — who, I may ask, would not rather 
admit that the nucleus had gradually cleared up in brightness, 
and assumed the lustre of a star, than have recourse to the 
most improbable of all hypotheses, that a fortuitous central 
meeting of a star and a nebula should be the cause of such a 
singular appearance ^ 
3. Of nebulous Stars.* 
The conjunction of the nebulous and sidereal condition is 
still more clearly manifested in nebulous stars. Having 
already described many of them in a paper read before the 
Royal Society in I shall here only mention tv/o of 
them. 
* See thirteen nebulous stars IV, 19. 25. 36. 38.44. 45. 52. 57. 58. 65. 69. 71. 74. 
