29 



wliicli show unmistakably that frequent alterations were then 

 going ou in the object. 



Since Mr. La Sueur left Melbourne the large telescope has 

 been under the charge of Mr. Farie McGeorge whose careful 

 research has brought more recent alterations to light,of which 

 he has given drawings down to the present time. 



Mr. H. C. Russell, B.A., of the Sydney Observatory, has 

 produced a large drawing showing considerable changes in 

 the object as seen with the Observatory telescope, which if I 

 rightly remember, is a seven feet achromatic. 



The good quality of an instrument best suited for showing 

 minute changes in nebulous matter is more important than its 

 size. Light, definition, and penetration, will show depth and 

 outline most distinctly. Two dissimilar instruments will seldom 

 shew configurations of nebulous matter alike. Powell and 

 Leyland's l-16th immersion lens, and Tolles' l-6th ditto, will 

 resolve Noberts' 19th band on his new test plate, when many 

 superior instruments and higher powers have failed to do so. 

 This difference in size and magnifying power^does not prove 

 that Noberts' 19th band is irresolvable— nor does the size 

 and magnifying power of the telescope prove that the Nebula 

 around v does not fluctuate. 



Sir J. Herschel did not wish to longer endorse the theory 

 of the concretion of nebulous matter into isolated stars ; this, 

 however, is not without its supporters. M. Delaunay, Cours 

 Mementair Astronomie, 4th Edition, — " In adopting the idea 

 of Herschel concerning the progressive condensation of nebu- 

 lae, and their transformation into stars, and applying these 

 ideas to our planetary system, Laplace arrived at the most 

 satisfactory mode of explaining their formation. " Exposition 

 du systeme du Monde." 



Mr. Procter releases himselfby a correction given in Nature, 

 for October 19th, 1871, page 487, from longer considering that 

 the fluctuations may be accounted for by an increased or de- 

 creased distance in space, but that the object is nearer than it 

 was formerly supposed to be. 



Another opinion offered is that of Mr. La Sueur, while 

 observing the object with the Melbourne reflector. " The 

 star n now shines with a light different from other stars in the 

 field, and more the colour of burning hydrogen," and, Mr. La 

 Sueur thought, " had consumed the nebula." 



How were the small coloured stars, seen lying on the dark 

 ground of the sky along with ^ produced ? — M. N., vol. 24, 

 page 5. They must either have been concreted from the 

 nebula as it drifted away, or by underlying it became visible 

 with the telescope when the nebulous matter was removed. 



Mr. Powell, of Madras, does not seem to have observed 



