24 



7tli magnitncle, that -q Argns cannot now be more than a 7th 

 magnitude star. In the catalogue there are two stars of the 

 6th and nine of the 7th magnitude, the remainder being all 

 of low magnitude. In the drawing the two 6th magnitude 

 stars are out of the field, and the nine of the 7th magnitude 

 in the field, are by careful comparison exactly the same mag- 

 nitude as V, which is left among tbem not marked. The 

 magnitudes of these stars are given by Sir J. Herschel, and 

 may be considered correct. 



Measures of these stars have recently been recorded ashaving 

 been made by small transit means ; but from my own experience 

 in such observations, I believe it all but impossible to measure 

 correctly such a cluster of small zenith stars by these means. 

 Two years ago I disxuounted a 24 inch transit by Varley in order 

 to re-place it with a 3 > inch by Dallmayer, made with a deep 

 diagonal eye-piece for the purpose of reaching small zenith 

 stars up to the 7th mag., as agreed upon for correcting any 

 error in longitude between Hobart Town and Melbourne. Mr. 

 Ellery selected 49 such stars, which were to be used at both 

 places, reversing the instiuments for each observation so as 

 to eliminate any errors. With these means, and for this pur- 

 pose, I find it difficult, and only under very favourable cir- 

 cumstances possible, to reach zenith stars of the 7th mag. My 

 reason for not attempting measures with the equatorial is in 

 consequence of a long experienced difficulty arising from the 

 want of clock movement, which I consider indispensable for 

 the accurate measurement of distances. I have therefore 

 preferred an eye and hand drawing when the object has been 

 inaconvenient position — approximately 75° from the meridian 

 towards the East, and 35° from the zenith. 



A very singular circumstance in connection with the extra- 

 ordinary object under consideration is, that although it has 

 within the last few years undergone such rapid changes, causing 

 great excitement amongst astronomers in Europe, and laying 

 a foundation for new theories— yet, apart from the Melbourne 

 Observatory, scarcely any one in the Australian colonies appears 

 to know it, notwithstanding that on every fine night through 

 the year it is to be seen above the horizon at Hobart Town, 

 and particularly well situated for examination, when near the 

 meridian. The only person who occasionally studied this object 

 with myself was a member of this Society — the late Joseph 

 Facy — who on suitable occasions would devote a few hours to 

 an inspection through the telescope of some of the principal 

 objects in the great Creator's workshop. He would, in his 

 pious zeal, apart from theological theories, frequently comment 

 upon the mode of manipulating, mechanical, geometrical, and 



