20 



NATURE 



[November 2, 191 1 



II. I3h. om. Ceres in conjunction with the Moon (Ceres 



0^48' S.). 

 16. 6h, 58m. Venus in conjunction with the Moon 



(Venus 1° 13' S.)- 

 18. 4h. om. Jupiter in conjunction with the Sun. 

 21. 2oh. 24m. Mercury in conjunction with the Moon 



(Mercury i° 28' N.). 



24. lyh. om. Mars at opposition to the Sun. 



25. 5h. 4ini. Uranus in conjunction with the Moon 



(Uranus 4° 44' N.)'. 

 ,, 2oh. om. Venus at greatest elongation W. of the Sun. 



Observations of Comets. — It appears from a note by 

 Mr. Knox Shaw, in No. 4531 of tlie AsXronomischc Nach- 

 richten, that the discovery of Borrelly's comet, 1911c 

 (1905 II.), was made with the Reynolds reflector, but was 

 a visual observation, photographs being secured later; the 

 comet's magnitude on September 19 was 130 to 13-5, and 

 there was no marked nucleus. 



Messrs. Innes and Wood describe the Johannesburg 

 observations of comets 19x16 (Kiess) and 191 id (Encke) 

 during August and September, and Mr. Innes compares 

 the reduced places of Encke 's comet with the positions 

 given in Dr. Backlund's ephemeris. The smoothed O-C 

 difference in R..'\. increases from 28-3s. on September 3 

 to +47-35. on September 14, the corresponding figures for 



Brooks's Comet (igiit), October 27, 4h. 45111. a.m. 



declination being —47' and -6-2' respectively. The 

 magnitude of the comet early in September was 9-5, and 

 the photographs were taken by Mr. Wood, with the 

 Franklin-Adams star camera, in exceedingly difficult 

 circumstances. Kiess's comet was of about fifth magni- 

 ture, and showed no tail on August 17, and then rapidly 

 faded to mag. 11-5 on September 17. 



Brooks's comet, 1911c, has been quite a conspicuous 

 feature of our early morning skies during the past week. 

 A naked-eye observation by Mr. Rolston at Gunnersbury 

 on October 27 showed a straight tail some 15° long, at 

 times seen to extend to 93 Leonis. The head was a little 

 less conspicuous than 5, but brighter than 6, Leonis ; thus 

 its magnitude would be about 3-0. As is shown in the 

 accompanying illustration, the comet, at 4h. 45m. a.m., 

 formed a striking triangle with j3 Leonis and the verv 

 brilliant Venus. At 5 a.m. on October 31 a tail some 12° 

 long was seen, and at times a further extension was 

 suspected. The head, seen through opera-glasses of low 

 power, had the appearance of a fairly bright homogeneous 

 disc ; to the naked eye it was no less conspicuous than 

 7 Virginis (mag. 2-8). 



NO. 2192, VOL. 88] 



Changes on Mars. — M. Jarry-Desloges, in a commu 

 cation to the Astronomische Nachrichten, No. 4531, st;i 

 that there is a bright area on the Mare Tyrrhenum simi. 

 to that already noted on Libya, and that the region? 

 Hesperia and .'Vusonia are completely modified si 

 October 12. This message is dated October 15 from 

 new observatory at S6tif, North Africa. In the s.i 

 journal there is a paragraph stating that observations h: 

 been carried on at this station since the end of Septemb 

 its position is long. =3° 4' 21' E. of Paris, lat.=36° 11' ; 

 N., and it is situated at 11 13 m. (3650 feet). At such 

 altitude the air is quite clear and suitable for astronom; 

 observations, and M. Jarry-Desloges hopes to be permit 

 to confirm observations of the Martian surface mad' 

 other observatories. To this end he asks for early 

 brief communication of the detection of any remark.i 

 phenomena ; the address for letters is : .^stronome 

 Service k I'Observatoire Jarry-Desloges, S^tif, Alger 

 and for telegrams : Observatoire S6tif, Algeria. 



Colour Photographs of Saturn. — Having secured : 

 colour photographs of Mars recently described in th 

 columns (October 19), M. Tikhoff turned his attention 

 a similar study of Saturn. It had been remarked, s« 

 years ago, by M. Belopolsky that the spectrum of the r'u 

 of Saturn appeared to extend further into the ultra-vi< 

 than did the spectrum of the disc, and this suggested 

 use of colour screens. With screens prepared by 

 Tikhoff, M. Belopolsky therefore employed the 30-i; 

 refractor in 1909 and during the earlier months of 

 present year to secure colour photographs of the plar 

 Two parts of the spectrum were used, the " indigo-viol' 

 (390-450 fifi) and the " yellow-green " (495-620 fifi). 

 Tikhoff examined the plates, and arrived at the follow 

 general conclusions. Passing from red to violet, the ditt 

 ence in intensity of the edges and centre of the ! 

 diminishes, and finally disappears ; the equatorial band 

 most brilliant in the red and darkest in the violet. J i ■ 

 behaviour of the rings is directly opposite to that of th^^ 

 ball, but the edges of the disc and the contiguous parts of 

 the rings are equally intense in all radiations. Observa- 

 tions of the spectra of the various parts confirm these con- 

 clusions, which may be explained by the presence of an 

 atmosphere about the disc and none about the rings. It 

 would also appear, from their similarity of transmission, 

 that the particles forming the rings and those forming th" 

 atmosphere about the disc are of similar magnitude ; that 

 is to say, the pulverulent particles of which the rings af^ 

 built up have diameters which, in the mean, are less than 

 wave-lengths of light. 



Aurora in Middle Latitudes. — Referring to Sir Lau 

 Brunton's letter describing a pseudo-aurora seen at " 

 Beatenburg, Switzerland, Dr. Krebs sends us a card ? 

 ing that he too saw flashes of light in the north, as s> 

 from Grossflotbek, at gh. lom. (G.M.T.) on August 21. 

 The sky was then nearly three-parts covered with cloud, 

 and thunderstorms prevailed about that period. A? - 

 possible explanation of the phenomenon he refers us to 

 article by himself in Urania, No. 9 (Februarv 26, 19 1 

 where he describes a light which he saw off Nantucket 

 May 15, 1909. which was seen from Blue Hill at 

 corresponding time. As seen by him it was in the N.F 

 N.W. region, but seen from Blue Hill it was south of ' 

 E.-W. line ; thus it lay between the two stations, betw- 

 lat. 405 N. and 42° N. Perturbations of the comp 

 accompanied the apparition, and it is suggested that 

 charged cloud capable of giving these and emitting : 

 flashes of light passed somewhere between the two static 



The Minor Planet 191 i M.T. — Dr. Palisa's descript: 

 of how he found the new and important minor pla 

 1911 M.T. is given in No. 4530 of the Asirotwmis 

 Nachrichten. He first drew it on his chart on S 

 tember 29, but found its position empty on October 

 When seen on this date the object appeared to presen: 

 nebulous appearance, suggesting the possibility of its bf : 

 a comet, but a further observation on October 4 negativ 

 this. 



