V 



for tlie Advancement of Science. 263 



The continuation of the observations on a Centauri at the Cape of 

 Good Hope has fully confirmed the result first obtained, — namely, 

 that the parallax of that star exceeds nine-tenths of a second, or that 

 its distance from the sun is about twenty billions of miles. So far 

 as we have the means of judging, this star is our nearest neighbor 

 in the sidereal spaces. The attention of foreign astronomers is siill 

 directed to the irregularities in the proper motions of stars, and the 

 opinion seems to be gaining ground that many of them are accompanied 

 by non-luminous companions. In our own solar system, the most re- 

 markable discovery is that (made independently, though on different 

 days, in America and In England) of a dusky ring interior to the well- 

 known rings of Saturn. It now appears that it had been seen several 

 years before ; but it then attracted no attention. How such a ring is 

 composed, and how sustained, are questions upon which perhaps the 

 physical astronomer may long employ himself. 



■But the discovery for which the year will be most frequently cited is 

 that of three additional planets, included in the same planetary space 

 belvveen Mars and Jupiter — In which eleven others had been previously 

 found. The last of these (Irene) discovered by Mr. Hind, observer in 

 the private observatory of Mr. Bishop, forms the fourth of his list, — and 

 makes his number llie greatest that any one man has ever discovered. 



Some time since, a grant was made by the British government for the 

 perfection of the Lunar Theory and Lunar Tables on which Prof. Han- 

 sen, of Gotha, had been engaged, but whose progress was slopped by the 

 interruption of funds in consequence of the unhappy Schleswig-Holstein 

 war. I understand that with the aid of this grant, equally honorable to 

 the British government and to the foreign philosopher, the svork is now 

 rapidly advancing. I have reason to believe that the theories of Ura- 

 nus and Neptune are now undergoing careful revision ; and I trust that 

 one of the elements most urgently required, namely, the mass of Nep- 

 tune, will be supplied from observations of Neptune's satellite made 

 with the large telescopes to which I have alluded. 



At the Edinburgh meeting, the attention of the Mathematical and 

 Physical Section was called by M. O. Struve (there present) to the 

 total eclipse of the sun which is to occur on the 28th day of the pres- 

 ent month; and the General Committee appointed a committee of 

 niembers of the Association to draw up suggestions for the observation 

 of the eclipse. These suggestions have been extensively distributed 

 both at home and abroad : and I am happy to announce one of the 

 results. After consideration of the singular appearances observed in 

 tne eclipse of 1842, it was determined by the committee to recommend 

 (among other things) that observing stations should be selected, if pos- 

 5^ible, in triplets: the three stations of each triplet having relation to 

 the north boundary, the centre, and the south boundary of the shadow. 

 The Russian government has fully adopted this suggestion; and has 

 actually equipped six triplets, including in all eighteen stations, with 

 observers and instruments for the observation of the eclipse. Russian 

 ^fficers in the Sea of Azov and the Black Sea will also observe it. 

 Since the issue of the suggestions, the observations made last year on 

 an eclipse visible at HonoTulu in the Sandwich Islands have been re- 



^^ived ; and they make us, if possible, still more desirous that the spirit 



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