23 



changes being principally confined to a space near to t? and 

 the so-called lemniscate* 



As some objections have been raised on the ground that 

 larger optical means than those employed by me are required 

 for recording truthfully the changes which occur in this object, 

 it may be well, perhaps, to state that the 5ft. equatorial pre- 

 viously mentioned, although the best for the purpose, is not 

 the only instrument at my command ; other telescopes have been 

 used in the open air, from a 3J inch Cook and Son's, to a 7ft. 

 Dollond — with, for the whole, a complete battery of Micro- 

 meters, and eye-pieces giving magnifying powers of from 25 

 to 450. This statement may go towards proving that with 

 due care such observations can be correctly made without very 

 large instruments. 



In Mr. Proctor's article on the Nebula in Argo, {Frazers 

 Magazine for December, 1868,) it is stated not to be quite 

 clear that the stars which appear in my drawing of 1868 have 

 been really copied from the view given by the telescope, &c. 

 In reply to this I beg to state that all the drawings, the 

 present, as well as the former ones, were carefully copied from 

 the object,as described in the Astronomical JRegistei^ for January, 

 1869. There is little doubt but that Mr. Proctor's views on 

 this subject would be much enlarged if he had the opportunity 

 of seeing the star and its Nebula as they appear in the tele- 

 scope, when above the Pole, at Hobart Town. 



Having now seen the object with the large Melbourne re- 

 flector, and compared the effect with that produced by my own 

 instruments during the last two years, I feel greater assurance 

 in communicating the result of observations on the changes 

 which have taken place since 1868. 



On comparing the present with the former drawing, it will 

 clearly appear that alterations ha.ve taken place, both in the 

 magnitude of the star 7;, and in the dispersion of the Nebula, 

 and from what follows it will be seen that the remarks made 

 by Professor Loomis and others on the period of this star are 

 premature. At the time of my visit to Melbourne (21st June 

 last), Mr. Ellery considered the star -n to be of the 7th mag- 

 nitude, and Mr. Le Suer thought it to be Q\. On returning 

 to Hobart Town, and resuming the observations on this in- 

 teresting object, I found by comparison with other stars, given 

 in the drawing and recorded in the Cape Catalogue as of the 



* I scarcely think this term a good one, Lemniscate, or Lemniscus — a 

 curve formed as the figure 8, or a bow tied of a riband (Barlow and B. 

 H. Smart). Such a curve is closed in the centre, which is not the case in 

 the Cape drawing, the space being there shown as a long enclosure, slightly- 

 compressed in the centre. It was in this compressed part of the dark 

 space that the star s- appeared when out of the dense Nebula in 1863. 



