Augtcst 9, 1877] 



NA TURE 



287 



The shower at 290° + 43° is appaiently new for the first half of 

 July, and corroborates one 1 deduced fiom the Italian meteor 

 catalogue (1S72) at 291° + 45° for June 26 to July 1 1 from eight 

 meteors. This position falls near an August shower (seen on the 

 loth in 1871 at 293 + 42), and it is very likely to be nothing 

 but an early indication of that system. The radiants in Perseus 

 at 47° + 45° and 36^ + 47" are too far removed from any pre- 

 viously known centres to be included with them. They weie 

 very swift, white mete6rs, rather bright, leaving streaks, and I 

 mistook them at first for early P^rseiJs of the true August 

 system. The positions agree singularly well with two of Prof. 

 Herschel's cometary radiants and dates (British Association 

 report on luminous meteors, 1S75, ?• ^33) as follows : — 



R.A. Dec. Date. 



Comets radiant (1764 B) ... 49° + 45°"S ... July 25. 



Meteor radiant, 1877 47+45 ... July 12-20. 



Comets radiant (770 tJ) ... 39 -I- 45 ... July 8. 



Meteor radiant, 1877 36 \ 47 ... July. 



I saw several meteors from these radiants in July last year, and 

 on examining the shooting-star catalogues of Zezioli, Schiaparelli, 

 Denza, and others, 1S67-72, have found a few additional paths 

 clearly confirming the existence of these new meteor orbits. 

 From twenty-eight shooting stars (including my own observa- 

 tions) the two showers are apparently well marked and fall 

 sufficiently near the cometary positions to afford an inference of 

 connection. 



The most active shower of the month was from Andromeda 

 (4° -)- 35°). Twenty-one swift white meteors were noted from 

 this place, but the radiant was a little diffuse and not nearly so 

 sharply centred as another strong system at 6 -^ 53, which 

 supplied very similar meteors. They are both already well- 

 known showers. On the early morning of the 29th a few swift 

 meteors with streaks, observed in Auriga, indicated the com- 

 mencement of the August Pcrseids with radiant near tj Persei. 



Bristol, July 31 W. F. Denning 



OUR ASTRONOMICAL COLUMN 

 The Total Eclipse of the Moon, August 23. — 

 Though lunar eclipses have lost the degree of astronomical 

 interest and utility formerly attached to them, the general 

 observer may still be expected to find the same amount 

 of attraction as in past times in watching the physical 

 features of a total eclipse of our satellite, well visible at a 

 convenient hour of a summer's night. On Thursday even- 

 ing, August 23, with favourable weather such a pheno- 

 menon may be witnessed, throughout its continuance, in 

 this country as in other parts of Europe. The first contact 

 with the penumbra takes place at Sh. 37m. Greenwich 

 mean time, and that with the dark shadow at gh. 137m., 

 about 59° from the northernmost point of the moon's 

 limb towards the east ; the total phase begins at 

 loh. 19'im., and ends at 37m. after midnight ; the last 

 contact with the shadow occurs at ih. 9'im. a.m. (August 

 24), about 112° from the northernmost point towards the 

 west, and that with the penumbra at 2h. ig'im. With 

 respect to the earth's true shadow the eclipse, therefore, 

 continues 3h.45m., and the moon is totally immersed in it 

 for ih. 45m., the middle of the eclipse at iih. iim. p.m. 

 When she first encounters the earth's dark shadow her 

 altitude at Greenwich is 18°. 



Though we are accustomed to speak of a total eclipse 

 of the moon, .-xs is well known, it rarely happens that she 

 disappears while in the earth's shadow. The physical 

 features of interest to which allusion is made above con- 

 sist chietly in the variations of the coppery and other 

 tints which spread over her surface, and in the great 

 majority of eclipses render her more or less conspicuously 

 visible, during her passage through the shadow ; and as 

 these variable features depend upon the state of the atmo- 

 sphere at the time round the edge of the earth's disc as 

 seen from the moon, with respect to transparency or more 

 or less prevalence of cloud therein — the aspect which a 

 particular eclipse is likely to present does not admit of 

 prediction. In the eclipse of June 15, 1620, Kepler states 

 that the moon wholly disappeared, while stars of the fifth 

 magnitude were visible in the neighbourhood, and He- 



velius failed to see her;;;even [with a telescope during the 

 eclipse of Aprii;i4, 1642 (not April 25, as stated in many 

 astronomical treatises). But perhaps one of the most 

 s'riking instances of the kind is afforded by the eclipse 

 of May 18, 1761, observed by the Swedish astronomer 

 Wargentin at Stockholm ; eleven minutes after the 

 total immersion he could not perceive the slightest trace 

 of the moon either with the naked eye or with the tele- 

 scope, yet the night was very clear and the stars shining 

 in her vicinity ; but about forty minutes later, with a two- 

 foot telescope, he discovered our satellite by a taint light 

 on the border of the disc. As an instance of the contrary 

 nature, where the moon has been so strongly illuminated 

 during her presence in the shadow, as to admit of the 

 various markings upon her surface being seen with dis- 

 tinctness, and even to lead persons to doubt her being 

 eclipsed, mention may be made of the eclipse on the 

 morning of December 23, 1703, which was observed by 

 various astronomers in the south of France. At Avignon, 

 during the whole duration of the passage through the 

 earth's shadow, " the moon appeared extraordinarily 

 illuminated, and of a very bright red, so that it might 

 have been supposed that she was transparent, and that 

 the sun was behind her globe, and that his rays passed 

 tlirough in the same manner that they are seen to traverse 

 certain stones, which are slightly diaphanous." It is 

 singular, however, that while this was the aspect of the 

 phenomenon at Avignon, different features should have 

 been noted at Montpellier, particularly the total disap- 

 pearance of the moon, rather quickly towards 6h. 30m. 

 A.^L, though the night was as transparent as could have 

 been wished ; it is mentioned that the twilight was already 

 very sensible, but that the invisibility of the moon could 

 not be wholly attributed to this cause, since many stars 

 were shining in the same quarter of the sky. A later 

 instance of the same kind occurred on March 19. 1S4S, 

 recorded by observers in England, Ireland, and Belgium, 

 when the moon's disc was intensely bright, coppery red. 

 The uninitiated were doubtful of there being any eclipse. 

 It is worthy of mention that conspicuous aurora borealis 

 was present during the night. 



The Variable Star x Cygni.— Prof. Schonfeld's 

 ephemeris fixes the next minimum of this star to 

 September 15, the magnitude according to his last cata- 

 logue of elements being then 12-8 ; but the variation has 

 been subject to considerable irregularity of late years, and 

 observations will be required for some time before and 

 after any dates now predicted to determine the epochs of 

 maxima and minima satisfactorily. The error of Arge- 

 lander's formula, with one perturbation, appears to have 

 attained a maximum of about three months, in 1S70, and 

 to have been since diminishing ; as compared with the 

 maximum of 1874, the error was little over two months. 



This star is properly designated x Cygni, Bayer's letter 

 undoubtedly applying to it. x °f Flamsteed must then 

 take the number he attaches to it, 17. When the British 

 astronomer looked for Bayer's star it would be, as 

 Argelander has pointed out, invisible ; and hence his 

 mistake in connecting another star with Bayer's letter ; 

 there is no necessity, however, to perpetuate the obvious 

 error. 



New Minor Planet.— No. 1 73 of the group of small 

 planets was discovered by M. Borrelly at the observatory 

 of Marseilles on the evening of the 2nd inst. At gh. om. 

 m.t., its position was in R.A. 22h. 40m. 30s., N.P.D. 

 97' 34'-8 ; diurnal motion in R.A. 26s., in N.P.D. , -\- 8', a 

 tenth magnitude. Though several small planets detected 

 within the last ten years are adrift, it does not appear that 

 the present body can be identical with any one of them. 

 Ephemerides for 1S77 of a number discovered since 152 

 are unavoidably omitted in the Berliner Jahrbuch for 

 1879, for want of the necessary elements. Dike, which 

 was found by M. Borrelly as far back as May, 1868, has 

 not been observed since. 



