April 14, 1910] 



NA TURE 



201 



OVR ASTRONOMICAL COLUMN. 



April Shooting Stars. — Mr. Denning writes : — " The 

 jibbous moon will be present in the sky during the ensuing 

 eturn of the April Lyrids, so that a conspicuously visible 

 iisplay can hardly be expected. The night of April 21 

 .vill probably be the time of maximum, but nothing can 

 )e definitely predicted as to the strength of the coming 

 diower. It seems to vary from year to year in an 

 rregular manner, and has seldom presented a rich display 

 :omparable with that of the August Perseids. 



' In 1909 there were few of the April Lyrids visible, 

 though the skies were very clear on the important nights 

 Df April 20 and 21. 



" The shower is, however, a very brief one, and often 

 vades English observers by occurring in the daytime or 

 at a period of cloudy weather or bright moonlight. It is 

 a system which certainly requires much further observa- 

 tion, though it seldom provides us with a spectacle of 

 abundant and attractive character ; but it may return at 

 any time and present a repetition of the splendid shower 

 witnessed in 1803, so that it should be carefully watched 

 every year." 



H alley's Comet. — The Cape Town correspondent of the 

 Daily Mail announces that Halley's comet was observed, 

 after its conjunction with the sun, at the Cape Observatory 

 at 5h. 50m. a.m. on April 8. The comet was visible for 

 ten minutes before becoming lost in the increasing day- 

 light, and is reported as being brighter than when seen in 

 February. The comet was observed at the Vienna Uni- 

 versity Observatory- shortly before 5.0 a.m. on April 11, 

 and was seen also at the Perth Observatory, Western 

 Australia. 



In No. 421 of the Observatory (p. 182) it is suggested 

 that, as Dr. Wolf saw the comet as a naked-eye object 

 on February 11, the estimated magnitude (90) given for 

 the end of February must have been far too low ; on the 

 assumption that the brightness varies as i/r^A^, the 

 comet should be at least as bright as the first magnitude 

 when near the earth on May 20. 



The question of the comet's brightness during May is 

 also discussed by Dr. Ebell in No. 4400 of the Astro- 

 nomische Nachrichten (p. 140). Taking the recorded 

 magnitudes, at various intervals from perihelion, during 

 the apparition of 1835-6, and comparing them with those 

 already recorded for the present return. Dr. Ebell finds 

 that the apparent magnitude at the time of greatest bright- 

 ness. May 21, may be about — 1-7, or about equal to that 

 of comet 1910a at its perihelion. On this basis the present 

 magnitude is about 40, and the comet should remain a 

 naked-eye object until" about the end of July. 



A photograph of the comet taken at Juvisy on 

 February 12 is reproduced in the April number of the 

 Bulletin de la Societe astronomique de France ; at that 

 time the tail showed as a feeble, fine trace about ij° long. 

 Another photograph was taken on March 7 with nineteen 

 minutes' exposure, but only a feeble image of the head was 

 obtained. A drawing by M. Baldet, made on March 5, 

 when the magnitude was estimated as 60, shows a 

 V-shaped appendage, the angle between the two tails being. 

 70°. and the southern tail being the faintest and shortest. 



Reports from various countries emphasise the necessity 

 for spreading sound knowledge concerning the comet. 

 The suicide of a Hungarian farmer " on account of 

 Halley's comet " is followed by a report from Odessa that 

 in southern Russia there is a veritable popular terror, 

 which is being exploited by unscrupulous persons for the 

 purpose of obtaining money, for special prayers, &c.. from 

 the ignorant natives. We welcome, therefore, a brochure 

 received from the Manila Weather Bureau, in which Father 

 Z.vack carefully analyses the alleged sources of catastrophe, 

 and shows how utterly puerile they are. Such brochures. 

 !l printed in the vernacular, would do a great deal towards 

 allaying excitement, which otherwise may lead to serious 

 trouble. 



Comet 1910a. — A number of observations- of, and an 

 ephemeris for, comet 1910a are published in No. 4400 of 

 the Astronomische Xachrichten. Among the former are 

 some, made near the end of January, by the late M. 

 Charlois at the Nice Observatory-, and an interesting set 

 communicated by Dr. Ristenpart from the Santiago! 1 Communicated by permission of the Tmstees of the British Museum 



NO. 2 III, VOL. 83] 



Observatory. At Santiago they picked up the comet about 

 three-quarters of an hour before noon on January 19. 

 (23h. 15m., January 18), and followed it until after 6 p.m. ; 

 at the time of the first observation it was only 7° east 

 and 3^° north of the sun. Herr Castro, who made the 

 position settings during the afternoon, noted a striking 

 falling ofif in the apparent brightness of the comet during 

 the 2^ hours he had it under observation. 



The Galactic System, its Structvre and Origi.v. — 



An interesting discussion of the galactic system, its struc- 

 ture, origin, and relations in space, is published — in 

 English — by Dr. Karl Bohlin in No. 10, vol. xliii., of 

 the Kungl. Svenska Vetenskapsakademiens Handlingar. 

 Having observed a large number of nebulae and clusters, 

 and, in a previous paper, discussed the measures of the 

 globular cluster M. 92, Dr. Bohlin was induced to take 

 up the study of the distribution of the various classes of 

 the heavenly bodies, and commenced with that of globular 

 clusters. From this point of view he has studied the dis- 

 tribution of a large number of these objects, and concludes 

 therefrom that their system is situated in the centre of the 

 galactic system, for only on this assumption can their 

 apparent clustering on one side of the galactic circle be 

 explained. Extending the study to various other classes of 

 celestial objects, the author evolves a systematic evolution 

 of them which accounts for their apparent distribution and 

 various forms. In this hypothesis planetary nebulae 

 originallv consist of rotating luminous shells filled with 

 verv tenuous matter. These shells, breaking down at their 

 poles, form apparent " ring " nebulae with distinguishable 

 nuclei. The galactic system is supposed to have been such 

 a planetarv nebula, having reached at present an advanced 

 form of ring nebula, of which the system of globular clusters 

 forms the nucleus ; the spiral nebulae, clustered near the 

 poles, parts of the broken shell : and the Milky Way. the 

 equatorial belt. Diagrams illustrating these distributions, 

 and twenty-seven reproductions from photographs of 

 various nebulas, are shown on the six plates accompanying 

 the paper. 



Saturn's Satellites and Rings. — In No. 610 of the 



revived Astronomical Journal, now edited by Prof. Lewis 

 Boss, Prof. Barnard records some measures of the eclipses 

 of Saturn's satellites, made by him during 1906-8. The 

 measures are given in detail, and some interesting notes 

 on the dimming of the satellites Rhea and Dione, immedi- 

 ately before the final disappearance, are appended. In the 

 case of the former the loss of light amounted to as much 

 as 20 to 2-5 magnitudes. Measures of the relative 

 distances of the satellites and of the position-angles of the 

 rings during the same period are also given. 



The System of e Herculis. — From the investigation of 

 a large number of plates taken at the Dominion Observa- 

 tory, Ottawa, Mr. Harper has re-determined the orbit of 

 the spectroscopic binary € Herculis. and finds several 

 departures from the elements determined from the 1Q07-S 

 spectrograms. The period, according to this later deter- 

 mination, is 402^5 davs, and is a varying quantity (the 

 Journal of the Royal Astronomical Society of Canada, 

 No. 5, vol. iii.). 



M 



THE GAZELLES OF SEISTAN.' 



AJOR R. L. KENNION, British Consul at Seistan, 

 has had the good fortune to bring to light what 

 are practically two new species of gazelle from the Kain 

 and Seistan districts of eastern Persia, specimens of both 

 of these, presented bv Major Kennion, being exhibited m 

 the Natural Historv Museum. Of the first of these species, 

 t\-pified bv the mounted head of a buck from Kain, two 

 notices bv myself appeared in the Field newspaper for 1908 

 (vol. cxi.', pp. 70 and 499). In the earlier of these it was 

 compared to the Atlas or edmi gazelle {Gazella cuvieri) and 

 Merrill's gazelle (G. merrilli) of Palestine, with the former 

 of which, and probably also with the latter, it agrees in 

 the presence of horns in the female. Compared with the 

 tvpe-skull of Merrill's gazelle figured by Mr. O. Thomas 

 in the Proceedings of the Zoological Society for 1904, voL 



