134 Astronomical Notes. 



highest authorities in stellar astronomy, has recently directed 

 attention to the subject. Forty years back he undertook an 

 elaborate computation of its place from the measures of Tycho, 

 which were taken with a sextant from eight neighbouring stars 

 in Oassiopea. These, as compared with the observations of 

 Bradley, W. Struve, Bessel, and Piazzi, give an average error 

 of + lm. 26s. in R.A., and — 13" in Deck, an amount by no 

 means discreditable to an instrument of comparatively rude 

 construction, and employed only with the naked eye. Its place 

 thus deduced will be, for 1865, R.A. 4h. 19m. 57-7s.-D.Isr. 

 63° 23' 55"*4. Our own great computer Hind had found a 

 result 3m. 10s. less in H.A., and 50" less in Deck, a difference 

 the cause of which could not be ascertained by Argelander 

 without a fuller explanation of Hind's mode of procedure. 

 But assuming the place as calculated by himself, Argelander 

 remarks that D' Arrest has observed a star, numbered by him 

 129, so nearly in the right position (that is, R.A.4h. 19m. 30s., 

 D.1ST. 63° 22 /, 9), that the difference does not exceed the un- 

 certainty of the old observations. This, of course, would not 

 be surprising amid the richness of the starry heavens; but 

 what has struck Argelander has been the circumstance that he 

 had formerly, with the 8-foot transit-instrument at Abo, sought 

 in vain for a star near this place, as well as subsequently (pro- 

 bably in 1849) with the meridian instrument at Bonn; and the 

 question has arisen in his mind whether D'Arrest's star, esti- 

 mated by him as of lO'll magnitude, may possibly be that 

 most wonderful phenomenon in a slowly-increasing stage. He 

 therefore entreats astronomers, who may possess sufficiently 

 powerful means, to keep watch upon this little star. It may 

 be added that the sudden development of the phenomenon of 

 1572 (as well as of those of 1604 and 1848) furnishes no serious 

 argument against its periodical character, for a great dispro- 

 portion between the times of increase and decrease is not 

 unfrequently associated with variable light, and in those less 

 observant days the earlier stages of its visibility would naturally 

 escape notice, till it became too conspicuous to be any longer 

 overlooked. It is not impossible that the parallax and distance 

 of this wonderful star might have fallen within the grasp of 

 such instruments as we now possess ; and it might even have 

 exhibited a visible and measurable disc, though this is less 

 probable from what is recorded as to the intensity of its scin- 

 tillation. But should any recurrent or fresh development of 

 this kind take place during the present generation, we may be 

 sure that the spectroscope of Mr. Huggins will be tasked to 

 the uttermost to ascertain its real character. 



