June 9, 1910J 



NATURE 



439 



Messrs. Hari'er and Brothers announce for publica- 

 tion during June " The Science of Happiness," Dr. Henry 

 S. Williams ; " The Elements : Speculations as to their 

 Nature and Origin," Sir William A. Tilden, F.R.S. ; 

 " Religion and Art in Ancient Greece," Prof. E. A. 

 Gardner; "Electric Trains," H. M. Hobart ; and "Con- 

 tinuous Current Machine Design," W. Cramp. 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences in June : — 

 fune 9. 5h. 3ni. Neptune in conjunction with the Moon 

 (Neptune 4'' 40' S.). 

 ,, i6h. i6m. Mais in conjunction with the Moon (Mars 



r 6' S.;. 



15. ih. 56m. Jupiter in conjunction with the Moon 



(Jupiter 3' 9' S.). 

 17. 2h. om. Mais at greatest heliocentric latitude N. 

 19. ih. om. Venus at greatest heliocentric latitude S. 

 , , I4h. om. Mercury ac greatest elongation (22" 43' W. ). 

 21. I9h. 49m. Sun enters sign of Cancer. 

 24. 3h. 5Sm. Uranus in conjunction with the Moon 



(Uranus 3" 50' N.). 

 27. I7h. om. Jupiter at quadrature to the Sun. 



Hallev's Comet. — With clear intervals between clouds 

 ing the past week, Halley's comet has not been a 

 _, —.cult naked-eye object for anyone who knew its posi- 

 tion approximately. 



Mr. Langton Cole reports that it was well seen at 

 Sutton, Surrey, on May 22 and 31, and on the former 

 occasion a short tail was visible to the naked eye ; he 

 estimates that on May 31 the comet was about as bright 

 as a star of the third magnitude. At Gunnersbury on 

 June I a naked-eye obser\'ation revealed the comet as 

 early as 9-15 p.m., when it was apparently fainter than 

 ij Leonis (mag. 3-6). 



A number of interesting notes on observations of the 

 comet at various European observatories appears in Nos. 

 4413 and 4414 of the Astronomische Xachrichten. In the 

 earlier number Dr. Franz records that on May 13, at the 

 Breslau Observator}, the comet did not appear to be so 

 bright as on earlier days ; a variability' of brightness is 

 suggested, and it will be interesting to see if this is con- 

 firmed by other observers. 



In No. 4414 many observers record that no trace of the 

 comet could be detected on the solar disc during the time 

 of transit. Dr. Wolf directs attention to the Bishop's 

 rings surrounding the sun and moon on May 19, and 

 suggests that they were more intense than if due solely to 

 atmospheric effects. Meteors and aurorae were looked for 

 at the Konigstuhl Observator}-, but were not seen. 



Polariscope observations at several observatories gave 

 similarly negative results. Prof. Franz records that on 

 May 19 two bright arcs of light were seen in the north- 

 west at Breslau, and may have been due to the comet. 

 According to a telegram from Prof. Sykora, the projection 

 of the comet on the sun was observed at Tashkent at 

 2ih. on May iS. An increased intensitj,- of the twilight at 

 Odessa on Slay 18 is ascribed by Prof. Donitch as possibly 

 due to cometary matter. Herr .\rchenhold reports a second 

 comet-like object 1° south of Halley's comet at gh. 30m. 

 (Berlin M.T.) on May 22, but the observation is not con- 

 firmed by special reports from Bergedorf and Heidelberg. 

 At Sonnwendstein, w^here, at an altitude of 1523 metres, 

 sev£ial German observers had gathered for observations of 

 the comet, the tail was observed from May 12 to 19. 

 During this period its apparent length increased from 32° 

 to 140° ; its apparent position was the same on May 19 

 as on May iS. Dr. Hartmann, who was one of the party 

 at Sonnwendstein, submits a special report dealing with 

 the various aspects of the tail, and directs attention to the 

 yellowish colour of the nucleus on May 20. 



A number of notes dealing with observations of the comet 

 were read at the meeting of the Paris Academy of Sciences 

 on May 30. and appear in No. 22 of the Comptes rendus. 



M. E. Marchand reports that observations made on the 

 Pic du Midi and at Bagneres-de-Bigorre were badly inter- 

 rupred by clouds. No striking special phenomena were 

 witnessed on May 18 and 19. but it was noted that the 

 dawn was especially bright and the sky tinted, as though 



NO. 2 119, VOL. 83] 



there were an exceptional amount of dust in the atmo- 

 sphere ; the appearance is likened to that which was 

 observed in 1902 and 1903 after the Martinique eruption. 

 The unusual halos around the sun and moon support this 

 view, as do also the observations of solar radiation sub- 

 s<-quentlv made at the Pic du Midi station. Observations 

 of the sun and of terrestrial magnetic and electrical effects 

 revealed no abnormal condition attributable to the presence 

 of the comet. t. c c 



M. Popoff reports on the observations made at the boha 

 Observatory (Bulgaria), and could not detect the comet 

 projected on the sun's disc. • . u 



Further obsen'ations made at Athens are dealt with by 

 M. Eginitis, who describes the forms of the nucleus and 

 tail on May 18-20. No extraordinar>- atmospheric effects 

 were recorded, and onlv two meteors were seen during the 

 nif^ht of Mav 18. A splendid bolide was observed in 

 Thessalv at i3h. 15m. (M.T. Athens), but is not connected 

 with the comet. Between 7 p.m. and 8 p.m. on May 20 

 the comet's tail was seen with the equatorial, and was 

 still apparentlv directed towards the west. The curvature 

 was so great that the earth could not pass through the tail 

 before the night of Mav 20. 



MM. J. Baillaud and G. Demetresco describe photographs 

 taken at the Paris Obser\atory on May 23, 24, and 28. 

 Onlv verv short exposures (thirty seconds to five minutes) 

 wpre possible, and the tail is not shown. The nucleus is 

 shown as an ellipse, the axes being 18" and 14" long. On 

 May 23 this ellipse, otherwise uniformly dense, showed a 

 condensation of 6" diameter at its N.E. extremity, but this 

 had disappeared on May 24. The nebulosit>- surrounding 

 the nucleus showed changes from one day to another, and 

 on May 24 recalled that surrounding the Pleiades star 

 Maia. 



The Spectroscopic Bin.«i¥ 3 Aurig.^. — In No. 22. 

 vol. i., of the Publications of the Allegheny Observatory 

 Mr. R. H. Baker discusses at length the observations of 

 /3 Auriga; as a spectroscopic binarv". Since the duplex 

 character of this star was announced by Miss Maurv' in 

 1889, manv observations have been made at Harvard, 

 Potsdam, Pulkowa, and Allegheny in an endeavour to 

 remove certain apparent anomalies from the observed orbit. 

 Assuming that the period was 39838 days. Miss Maury 

 found, from the discussion of some 200 plates taken at 

 Harvard, that there was an apparent reciprocal variation 

 of intensitv between the two components, but Mr. Baker 

 now shows' that this is not so ; owing to the assumed period 

 being slightlv in error, the two components were alternately 

 misidentified'. The discussion of the Allegheny observations 

 with those previouslv published shows that the orbit is 

 practicallv circular (e = o-o± 0-0057), and that there is prob- 

 abiv a slight variation in the period, amounting to 00000 10 

 dav, or o-86s. per annum. The period now given is 

 3-960027 davs -1- 0-000010/ ±0-000004 days, the present 

 elements being referred to the epoch 1905 September 

 11-7324, G.M.T. 



An investigation of t-he secondary' oscillation found by 

 some observers is not confirmed, nor was Mr. Baker able 

 to find evidence for the dispersion of light during its passage 

 through space from 3 .\urigae to the earth. 



The Brightness of the Sky. — Commenting upon M. 

 Fabry's recent determination of the brightness of the sky, 

 Mr. 'Gavin Burns brings together, in No. 422 of the 

 Observatory, the results obtained by various obseri-ers ; they 

 are as follows, each value being the brightness of one 

 square degree of non-galactic sky expressed in terms of a 

 fifth-magnitude star : — Newcomb, 1-15 ; Burns, 2 ; Townley, 

 2; Yntema, 5-76; Fabrj", 1-46. Mr. Burns remarks that 

 if, as seems probable, the brightness is a variable quantity, 

 the results obtained by different observers are bound to vary 

 considerably inter se. 



The .Accuracy of Radhl-velocity Determin.\tioxs. — 

 In No. 4, vol. xxxi., of the Astrophysical Journal Prof. 

 Frost issues a timely warning against attributing too great 

 an accuracy to present-day determination of radial veloci- 

 ties. .\ tabulation of twelve values recently obtained by 

 various observers for Arcturus, a simple problem, shows 

 that they var>- between —3-7 km. and —6-6 km., whilst 

 the extreme range for any one observer varies from 1-2 km. 

 to 4-5 km. Prof. Frost questions if we know the radial 

 velocity of any star to the nearest kilometre. 



