May 7, 1896J 



NA TURE 



subject-matter to any other mathematical jnurnal in the United 

 Kingdom. 



Messrs. Dui.au axd Co. have just issued a catalogue (No. 

 XV.) of works on geographical botany, containing more than 

 four thousand titles, offered for sale by them. 



The Appendix of " Quain's Elements of Anatomy " (Long- 

 mans, Green, and Co.), which completes the tenth edition of the 

 work, has now been published. The subject, " Superficial and 

 .Surgical Anatomy," is treated by Profs. C. D. Thane and R. J. 

 Godlec. 



We learn from the current (and final) number of the Anuricaii 

 Meteorological Journal, that the New England Meteorological 

 Society has been dissolved. It was formed in Boston, in June 

 1884, to jiromote the study of atmospheric phenomena in the 

 New England States, and to establish systematic observation. 

 It has done much useful work, especially relating to rainfall, 

 thunderstorms and range of temperature, the results of which 

 have from time to time been published in the above-named 

 journal. The system of regular meteorological observations 

 and the publication of a monthly bulletin were transferred to 

 the New England Weather Service, in connection with the 

 Washington Weather Bureau, several years ago. 



The Rebman Publishing Company have issued the first 

 number of the Archives of Clinical Skiagraphy, by Mr. Sydney 

 Rowland, being the commencement of a series of collotype illus- 

 trations, with descriptive text, illustrating applications of the 

 new photography to medicine and surgery. In an introduction 

 Mr. Rowland gives a brief account of Rontgen's discovery, and 

 describes the great advantages obtained by the use of the form 

 of Crookes' tube known as the focus tube, devised by Mr. 

 Herbert Jackson. The excellent results obtained by British 

 investigators working with X-rays are almost entirely due to the 

 introduction of this form of tube. As to the constitution of 

 fluorescent screens, Mr. Rowland agrees with the conclusion 

 arrived at by Mr. Jackson after a systematic examination of 

 numerous substances, viz; that the best salt to use is platino- 

 cyanide of potassium. The plates included in the present 

 number of the Archives show the skeleton of a full-grown child, 

 aged three months (exposure fourteen minutes), a needle em- 

 bedded in a finger (exposure two minutes), knee-joint, from a 

 case of multiple exostosis (exposure nine minutes), and hand of 

 same case (exposure three minutes), wrist and forearm showing 

 syphilitic disease of radius (exposure six minutes). The illus- 

 trations may be taken as an indication of how the Riintgen 

 photography is able to supplement diagnosis in all cases of bony 

 disease. It is really astonishing to think that, though Prof. 

 Rontgen's discovery is but a few months old. it has already 

 taken its ])lace among the approved and accepted aids to dia- 

 gnosis, and a publication has been started to deal with its 

 developments in medicine and surgery. 



The additions to the Zoological Society's Gardens during the 

 past week include a Rhesus Monkey {Macaciis rhesus, i ) from 

 India, presented by Mr. E. Turnham ; a P'ennec Fox (Canis 

 cerdo) from Egypt, presented by Mr. J. d. Mackie ; a Mexican 

 Skunk (Mephitis inacrtira) from Mexico, presented by Mr. 

 Henry Heath Cochrane; a Brahminy Kite {Haliastur Indus) 

 from India, presented by Mr. A. Kemniis-Betty ; an African 

 Tantalus (Tantalus ibis), a Leopard Tortoise (Testudo pardalis) 

 from East .\frica, presented by Captain Dugmore ; a Canary 

 Finch (Serinus canarius) from Madeira, presented by Mr. H. 

 B. Hewetson ; a Great Wallaroo (Macropus robustus, 9 ), a 

 Gould's Mf)nitor ( Varanus gouldi), a Black and Yellow Cyclodus 

 (Cyclodus nigroluteus) from Australia, a \ellow-headed Conure 

 (Conurus jendaya), iwo Brazilian Tortoises (Testudo tabulata) 

 from Brazil, five Meyer's Parrots (Pirucophalus ineyeri), two 

 NO. 1384, VOL. 54] 



.\lario Sparrows ( Passer alario) from South Africa, a Brown- 

 throated Conure (Conurus aruginosus) from South America, 

 deposited ; a Chimpanzee (Anthropopithecus troglodytes, 9 ) 

 from West Africa, a Red-naped Fruit-Bat (Pteropus funereus), 



Bandicoot (Pcramclcs ) from Australia, two Spotted 



Tinamous (Nothura maculosa) from Buenos Ayres, purchased. 



OUR ASTRONOMICAL COLUMN. 



Thk Planet Mercury. — An unusually good opportunity of 

 observing the planet Mercury with the naked eye, or with an 

 opera-glass, will be afforded about the middle of the present 

 month. The planet will be at its greatest eastern elongation on 

 May 16, when it will be 22° from the sun, and will remain above 

 the horizon for two hours and a quarter after sunset. At this 

 time the apparent diameter of the planet will be S", and about 

 o"4 of the disc will be illuminated. On May 14, at 6 p.m., the 

 planet will be in conjunction with the moon. Mercury being 

 2° 24' to the south ; at 9 p.m. on the same evening, the crescent 

 of the two days' moon will be about 3" N.N. E. of the planet. 



Comet Swift 1896. — The following continued ephemeris 

 for the new comet is from revised elements computed by Dr. 

 Schorr for Berlin midnight : — 



R.A. Decl. Brightness. 



Ii. m. s. . , 



May 8 ... 2 12 41 ... 4-62 58-1 



K) ... I 58 52 ... 64 46'! ... 0'35 



12 ... I 44 41 ... 66 1 7 '4 



14 ... I 30 19 ... +67 33-9 ... 0-26 

 The unit of brightness is that on April 16. The comet was 



easily visible in a three-inch telescope on April 30, when the 

 computed brightness was o"7- 



New Divisions of Saturn's Rings. — In the current num- 

 ber of the Comptcs rendiis, M. Flammarion gives particulars 

 of some very interesting observations of Saturn's rings which 

 have been made at his observatory by M. Antoniadi during the 

 last month. Between the Cassini division and the Crape ring, 

 three new divisions of the ring have been noted. The darkest 

 of these, which is easily visible when the air is transparent, 

 nearly bisects the inner bright ring ; the fainter divisions, one 

 on each side, are only observed with difficulty. The inner 

 bright ring is thus divided into four zones, gradually darkening 

 towards the planet. 



This is by no means' the first time that divisions of this kind 

 have been recognised. Herschel, De Vico, Bond,t Hall, and 

 others, have in turn observed or suspected them, but Cassini's 

 division is the only one which seems to be certainly permanent. 

 M. Flammarion concludes that the fainter divisions observed on 

 the rings are variable, and po.ssibly dependent upon the varying 

 attractions of the eight satellites upon the meteoritic particles of 

 which the rings are composed. 



Determination of the General Brightness of the 

 Corona. — In the current number (vol. vi. No. 6) oi\ht Journal 

 of the British Astronomical Association, Mr. Joseph Lunt 

 suggests a method by which a numerical value could be obtained 

 for the general photographic intensity of the light of the corona 

 during a total solar eclipse. 



The method consists in photographing a " sensitometer 

 window," consisting of twenty-five numbered squares of 

 graduated opacities (like a Warnerke's sensitometer, but with 

 difterent values). The opacities are .so adjusted that an exposure 

 of ninety seconds to full moon-light, which appro.ximates 10 the 

 coronal light, should yield a negative showing the figure 12. 

 The negative could be obtained either by direct contact with the 

 "sensitometer window" (as in lantern-slide making), or by 

 forming an image of the " window '' on the plate by means of a 

 lens. The plates could be standardised by exposure to any 

 standard artificial light or to full moon-light, according to 

 Mr. Maunders' suggestion, in order to reproduce the precise 

 illumination of the sensitometer window given by the corona. 

 The conditions of development of the negatives for comparison 

 should be identical, and the plates used should all be of identical 

 sensitiveness. 



The apparatus required is very simple, consisting of a box of 

 square section, about three feet long, closed at one end by a 

 i-plate dark slide, and at the other by the J-plate sensitometer, 



