17 



apparent features of the nebula, and render manifest changes 

 of a somewhat different character to those here described. To 

 witness these effects I wait the arrival of the Melbourne 

 telescope, when I hope to have the opportunity of more 

 correctly verifying these statements. The investigation of the 

 fluctuations connected with the object v Argus and surround- 

 ing nebula appears not to require such refined and delicate 

 observations as were bestowed upon Herchel's subnebulous 

 region near the trapezone in Orion, by the late Professor 

 Bond, and Earl of Rosse, nor are such powerful instruments 

 necessary. Take, for instance, the position of the star v, as 

 given by Sir J. Herschel, at the Cape of Good Hope, and note 

 its position again, when in the dark space as confirmed by 

 E. P. Powell, Esq., at Madras — and now for the third time 

 compare its situation removed from the dark space altogether 

 to quite a different portion of the nebula, and it will appear 

 clear that the optical means employed have been ample, not- 

 withstanding Mr. Powell was at first inclined to think that 

 the fluctuations were only apparent, and owing to the 

 inferiority of his instrument. The beautiful soft white light 

 given out by the nebulous matter about rj Argus appears to 

 be produced, either from the increased magnitude of the stars, 

 or the displacement of some of the nebulous mass, or probably 

 from both, for in the former case it is difficult to say (only 

 from its position) which is v Argus and which is not, there 

 being so great a similarity in its size and that of some of the 

 accompanying stars. On a clear fine night the object gives 

 out fully twice as much light as that of the great nebula — 

 nebicula major, — and about three times as much as nebicula 

 minor, irrespective of size. In the twilight it appears as soon 

 as a star of the second or third magnitude the light being 

 white and more diffused — very like a small white woolly cloud 

 on a blue sky, seen in sunlight. It is also seen in full moon- 

 light, when all other nebulous matter is obscured. At present 

 there appears to be no further diminution in the magnitude 

 of the star below the 6th. Being in Melbourne on the night 

 of the 25th March, 1865, which was a very fine one, and 

 happening to look towards t? Argus I fancied that the star 

 appeared as a distinct point in the nebula. I immediately 

 proceeded to the observatory, Mr. Ellery with his ac- 

 customed kindness allowing me to take possession of the 

 equatorial, and on examining the object found the colour of 

 the accompanying stars to be the same as before described to 

 the society, and, with the comjDarative eye-piece, considered 

 the star v to be 5*5. It was about this time that Mr. Tebbutt, 

 of New South Wales, forwarded the result of his observations 

 to the society, giving the star as 5*5. This appearance, how- 



