March 13, 1913] 



NATURE 



41 



OUR ASTRONOMICAL COLUMN. 



The Use of a Plane Grating in Stellar Spectro- 

 scopy. — In No. 5, vol. vi., of the Journal of the Royal 

 Astronomical Society (Canada) there is an interesting 

 note describing some preliminary tests, made at the 

 Dominion Observatory, Ottawa, of a plane grating 

 used as the dispersion piece of a stellar spectrograph. 

 The grating used is one ruled by Dr. J. A. Anderson, 

 who is now regularly ruling excellent gratings at the 

 Johns Hopkins University, and has a ruled surface 

 of 2f x 35 in., with 15,000 lines to the inch. It was 

 employed in the Littrow form of spectrograph, giving 

 a linear dispersion of 17-5 Angstroms per millimetre, 

 and gave excellent definition over a nearly fiat field 

 extending from A4800 to A3500. The photographs 

 secured show a much more uniform intensity over 

 a wide range than do those taken with a three-prism 

 spectrograph, and for this reason will be especially 

 useful. In the red, where the prismatic spectrum is 

 so compressed, and in the violet and ultra-violet, 

 where it suffers considerable absorption, the grating - 

 spectrograph will prove very advantageous, and the 

 results of the further experiments to be made will be 

 awaited with interest. 



Observations of the Zodiacal Light. — The 

 February number of L' Astronomic contains two strik- 

 ing drawings of the zodiacal light as seen by Lieut. - 

 Col. Pachine at Essentouki (Caucasus) on January 28, 

 191 1. This observer has seen the phenomena many 

 times, and in various countries, but had never before 

 seen it so brisdit. At 6h. 30m. p.m., the base of the 

 luminosity extended along the western horizon for a 

 distance of some 30 from a Piscis Austr. towards 

 Aquila, and the cone reached upwards to a point a 

 little to the south of a Arietis, the brightness from 

 the base to 7 Pegasi being more than twice that of the 

 Milky Way in its brightest parts. Many curious fluc- 

 tuations took place, and at gh. 40m. the apex of the 

 cone enveloped the Pleiades. The colour of the light 

 generallv was from a pale-yellow to a bluish-grey. 



Astronomical Time-installations. — A brochure 

 published by the Royal Observatory of Belgium con- 

 tains a very detailed and well-illustrated account of the 

 installations employed for the time-service in that 

 observatory, written by MM. Philippot and Delporte. 

 The various means employed to secure the necessary- 

 constancy of pressure and temperature in the under- 

 ground chamber containing the installation are very 

 interesting, as are also the various devices for auto- 

 matic regulation and registration, and it would appear 

 that the Belgian authorities have established an ideal 

 installation for their time-service. 



Amateur astronomers will find a useful note, by 

 M. Jonckheere, in the January number of L'Astro- 

 nomie, describing a device he employs for keeping his 

 sidereal clock at constant temperature. The clock is 

 placed in a double case, and should a change of tem- 

 perature occur, a current is sent automatically through 

 a heating circuit (an incandescent lamp bulb) until 

 equilibrium is restored. With this apparatus M. 

 Jonckheer keeps the temperature constant within 

 0-2S C. 



ORNITHOLOGICAL NOTES. 



TN the fifth part (vol. i.) of The Austral Avian Record 

 *■ the editor executes a complete volte fare in the 

 matter of the classification of Australian birds. 

 Hitherto he has used generic terms in a wide and 

 comprehensive sense; he now employs them in a 

 much more restricted signification, and accordingly 



no. 2263, VOL - 9 1 ] 



proposes no fewer than forty-eight new genera in this 

 issue. Whether such changes be expedient or not 

 Inhere is no right or wrong in the matter), they have 

 the great disadvantage of rendering standard works, 

 like Sharpe's "Hand-list of Birds," more or less 

 obsolete. 



In The Zoologist for December, iyi2, Mr. F. J. 

 Stubbs gives reasons for regarding migration as a 

 cosmical function, which plays an important part in 

 regulating the present balance of life on the globe. 

 The prevalence of continuous sunlight during the 

 Arctic summer and its absence in winter is regarded 

 as the primary controlling factor of the phenomenon. 



Bird-migration in Lindisfarne forms the subject of 

 an editorial article in British Birds for December, 

 1912. Rather more than a hundred kinds of birds 

 were observed on the island, of which not more than 

 thirty seemed to be resident. Although no great 

 inrush of birds was noticed, migration was going on 

 during twenty-six out of the forty days of the visit. 

 Bird-life in the south-west of Ireland and the recovery 

 of birds marked in 1912 form two of the chief items 

 in the January issue of the same journal. 



Bird-marking in the Netherlands forms the subject 

 of an article by Dr. E. D. Van Oort in Notes Leyden 

 Mus., vol. xxxiv., p. 243. The number of birds 

 marked in 1912 was considerably greater than in the 

 preceding year. The record includes such birds of 

 both years as have been recovered up to date, but the 

 returns from correspondents were not complete when 

 the article was written. 



In the course of a narrative of a trip through South 

 America, including a visit to Tierra del Fuego, which 

 deals chiefly with ornithology, Mr. F. W. Blaauw 

 (Notes Leyden Mus., vol. xxxv., No. 1) describes the 

 nestling plumage of the so-called Coscoroba swan 

 (Coscoroba Candida), and its bearing on the affinities 

 of the genus. The colour-pattern is intermediate 

 between those of sheldrake and tree-duck chicks, the 

 head-markings approximating to, and the body-mark- 

 ings being almost identical with, those of the latter. 

 This tends in some degree to confirm the author's 

 view that Coscorobas arc practically overgrown tree- 

 ducks. 



It is satisfactory to learn, from a report by Mr. G. 

 Bolam on the natural history of Hornsea Mere, pub- 

 lished in the January number of The Naturalist, that 

 the local birds are most efficiently protected by the 

 keeper, who has occupied his post for thirty-two years. 

 It may be noted that in 191 1 fourteen bearded tits 

 were introduced, some of which have nested and 

 reared young. 



In a long article on the " Hand-list of British 

 Birds," by Dr. Hartert and others, published by 

 Messrs. Witherby, The Field of March 8 strongly 

 condemns the great changes in familiar nomenclature 

 which form one of the most striking features in that 

 work, referring especially to the inconvenience caused 

 by transferring names long associated with well- 

 known species to others. At the conclusion of the 

 article it is suggested that those "who mav be in 

 doubt whether to accept or reject the list now under 

 consideration will do well to await the appearance of 

 a new edition of the B.O.L. List, which, we under- 

 stand, is in active preparation. The simplest way 

 out of the difficulty, as it seems to us, is to ignore 

 the new list." 



Last year schedules were distributed throughout the 

 country with the object of obtaining data with 

 regard to the alleged decrease during the last few- 

 years in the numbers of certain migratory species 

 which regularly visit the British Islands. Although 

 the returns are not so full or so numerous as is 

 j desirable, they afford a considerable amount of in- 



