Saturn's Ring. — Double Stars. — Occultations. 435 



Hindis New Star in 1848, which broke out at no great distance 

 from the place of that in 1604, barely surpassed the 5th mag.; 

 but as an equally, if not more conspicuous star blazed forth in 

 Cassiopea in 1572, and there are obscure relations, especially 

 in the Qhinese records, of similar events in earlier ages, we 

 are warranted in not despairing of witnessing such a glorious 

 sight again, and possibly of getting some approximate idea of 

 its distance and magnitude. Thus far only we can see at pre- 

 sent that both must be immensely great, as such phenomena 

 undoubtedly lie far beyond the planetary system, and in the 

 true region of the stars. Imagination shrinks from the con- 

 templation of the impenetrable mystery of their nature, not 

 without some appreciation of the astounding magnitude of the 

 change indicated by so sudden an evolution of most vivid light, 

 and probably corresponding heat also. Whether the new star 

 in the 2nd century B.C., which we are told induced Hipparchus 

 to form the first catalogue, was of this character, seems doubt- 

 ful. It is strange that among all the authorities whom I have 

 consulted, not one, excepting Humboldt, alludes to the curious 

 fact that Pliny, from whom we have the story, expressly ascribes 

 ■motion to the new object;* Humboldt, who was aware of it, 

 has not much confidence in Pliny's "rhetorical style;" but the 

 expressions of the latter seem as explicit as could in reason be 

 expected. 



Having now reviewed the principal double stars near the S. 

 horizon, we will proceed to a constellation — Bootes — which will 

 be in sight some time, but part of which we had better take at 

 once, since work will crowd upon us as the days decline. And 

 here Arcturus (a Bootis) shall be our guide. Every observer 

 will easily recognize him at a considerable height in the S.W. 

 sky, as one of the most conspicuous ornaments of our summer 

 evenings. ■ Wega, further E., and near the zenith, alone rivals, 

 with its lovely sapphire beam, this glowing topaz. Observers 

 have differed as to their precedency. In 1806, Sir W. Herschel 

 gave the preference to Arcturus; and his son has done the 

 same in the proportion of 718 to 510; Seidel, on the contrary, 

 in 1846, with SteinheiPs photometer, gives Wega 100, Arcturus 

 84. Photometry, however, is confessedly in an imperfect state ; 

 and it is not only possible, as Smyth remarks, that ee colour 

 may interfere with our exact perception of size," but it has 

 been shown by Argelander and Pogson that in the case of red 

 and white stars there is a considerable difference in the estimates 

 of different eyes and telescopes. Fletcher has also found that 

 the light of Arcturus is slightly variable. On the whole, how- 



* JSToyam stellam et aliani in sere- suo genitam deprehendit : ejusque niotu, 

 qua die fulsit, ad dubitationem est adductus anne hoc srepius fieret, moverentur- 

 que et eee, quas putamus affixas.— Sistoria Mundi, ii. 26. 



