19 



in the letter, D.D., C.C, (^), («), B.C., (E.), 522, 558, 640, 

 337, 383, 415, (7), (a), &c., &c. There are many other stars in 

 my copy of 1870 that are not laid down in plate 4, pricked 

 off from Lieutenant Herschel's drawing. 



The other question of note refers to my " having placed 

 within 11^ (on the scale of my drawing of (v) five stars of 

 magnitude at least equal to -n, that is, the 7th magnitude, 

 while in Sir J. Herschel's monograph only one star of that 

 magnitude (marked C.) occurs within that distance ;" and con- 

 tinues, " can you give any elucidation of the cause of the dis- 

 crepancy ?" also "if you would furnish some instrumental 

 determination of the difference of E.A., and P.D., between 17 

 and other stars of equal magnitudes." 



In my acknowledgment of this letter to Mr. William 

 Huggins, F.E.S., &c., I mentioned that it was not my inten- 

 tion or desire to dispute either Sir John's or Lieutenant 

 Herschel's configurations, but to call the attention of the as- 

 tronomical world to the altered features of both the star 

 and the nebula, with a view of obtaining a solution of the 

 changes seen in this most remarkable object. I further stated 

 that the above question was of a physical nature, and could 

 only be answered as such. 



On reference to my former papers it will be seen that 

 mention is made, more than once, of the fact that the in- 

 crease of stars of the same magnitude as v render it difficult 

 to know that star from others, but by its position, and a 

 marked difference in the li^ht. The present drawing will show 

 a still greater and more remarkable number of stars of a 

 similar magnitude. 



It is to this cause I have so frequently referred the in- 

 crease of light, which I think is now clearly confirmed by a 

 comparison of Lieutenant Herschel's description with that of 

 Sir John. At one of the monthly meetings of the Society, Sir 

 John Herschel considered the increase of light in the object, 

 as recorded, very strange, and remarked " when I was at the 

 Cape the nebula could not be seen at all with the naked eye.'* 

 Lieutenant Herschel, when at Bangalore, compared the in- 

 creased light, when the object was only 15 *^ above the horizon, 

 to that of Pleiades in Taurus. 



Mr. Le Sueur, in his report on the Melbourne reflector, 

 says " the nebula around v Argus has changed largely in shape 

 since Sir J. Herschel was at the Cape. The star shines with 

 the light of burning hydrogen," and in his opinion " has con- 

 sumed the nebula." 



At the monthly meeting of the Eoyal Society of Victoria, 

 held on the 13th March, 1871, Mr. Fairie McGeorge, who has 

 now charge of the reflecting telescope at the Melbourne Obser- 



C 



