September 6, 1900] 



NATURE 



459 



■ 



new edition — containing numerous alterations and additions, 

 while retaining the original form — has just been published, and 

 it should be possessed by every lover of country rambles or 

 teacher of earth-knowledge. 



A BULKY volume, containing "Agricultural Statistics of 

 British India for the years 1894-95 to 1898-99," has just been 

 distributed by the Department of Revenue and Agriculture of 

 the Government of India. The tables show (i) total average, 

 classification of areas, irrigation, fallow land, area under crops, 

 and stock ; (2) prices of produce ; (3) incidence of the land 

 revenue on area and population ; (4) varieties of tenure held 

 direct from Government ; (5) register of transfers of landed pro- 

 perty ; and (6) yields of principal crops. 



The additions to the Zoological Society's Gardens during the 

 past week include a Green Monkey {Cercopithectis callitrichtis, <J ) 

 from West Africa, presented by Mr. C. A. Gilbert ; two Bosch- 

 boks [Trage/aphus sylvaiicus) from South Africa, presented by 

 Dr. A. MacCarthy Morrough ; a Rufous-necked Wallaby 

 {Macropus rttficollis) from New South Wales, presented by Miss 

 Seymour ; a Germain's Peacock Pheasant {Polypkctron ger- 

 maini) from Cochin China, presented by Mr. Arthur Yates ; a 

 Common Boa {Boa constrictor) from South America, presented 

 by Mr. G. R. Fairbanks ; two Red-bellied Squirrels (Sciurus 

 variegatus) from South America, a Yellow- fronted Amazon 

 (Chrysotis ochrocephala) from Guiana, ten Roofed Terrapins 

 {Kcuhuga tecttiin) from India, deposited ; a Wapiti Deer (Cervtts 

 canadensis), two Collared Fruit Bats (Cynonycteris collaris), 

 born in the Gardens ; two White Ibises [Endocitiius albus), bred 

 in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Ephemeris for Observations of Eros. — In the last issue 

 of the Astronomische Nachrichten (Bd. 153, No. 3660), Signor 

 E. Millosevich gives a revised ephemeris of this asteroid for the 

 next few weeks : — 



Ephemeris for I ih. Berlin Mean Time. 



R.A. 



Decl. 



Sept. 



2 27 24-16 ... -t-35 29 537 



28 28-18 ... 35 52 13-0 



29 30-73 ... 36 14 36-1 



30 31-77 ... 36 37 2-8 



31 31-22 ... 36 59 33-0 



32 2903 ... 37 22 6 8 



33 25-13 ••• 37 44 43'9 

 2 34 19-43 ■•• +38 7 24-2 



Comet Swift (1894 lY). — Mr. F. H. Scares has calculated 

 the osculaiing elements, and from them computed a finding 

 ephemeris for this comet, which may possibly have some con- 

 nection with the lost comet of De Vico. As it is important, how- 

 ever, that the comet should again be observed before any further 

 attempt is made to establish such connection, he hopes that all 

 possessing the necessary optical power will prosecute the search 

 for it {Aslronomische Nachrichten, Bd. 153, No. 3656). 

 Osculating Elements. 

 Epoch and Osculation 1900 July 23 o Berlin Mean Time. 



M = 3i7 16 15-0 



•K -348 56 56-0'! 



J^ = 24 50 38-8 -1900-0 



i= 3 35 17 oj 

 .J) = 31 2 30-2 

 M=5.';4"-3823 



Ephemeris for Berlin Mean Midnight. 

 150C. R.A. Decl. 



9 ... 16 27 21 ... -2°5 21 9 



13 ... 32 57 ... 25 305 



17 ... 38 55 ... 25 391 



21 ... 45 15 • ■ 25 47-5 



25 .. 51 56 ... 25 55-6 



29 ... 16 58 57 ... -26 3-1 



NO. 161O. VOL. 62] 



Sept. 



The New SfECTROc.RAi'Hs for the Potsdam Great 

 Refractor. — In the Astrophysical Journal, vol, xi. pp. 393- 

 399, Prof. H. C. Vogel describes the two new spectrographs 

 which have recently been completed for the great Potsdam 

 refractor of 80 cm. aperture. 



(a) Three-prism spectrograph. — This is designed so that the 

 combined deviations of the three prisms shall be nearly 180°, 

 thus bringing the collimator and camera almost parallel. These 

 are then mounted on a massive steel plate 78 cm. long, 41 cm. 

 broad, and 7 mm. thick, which in its turn is firmly attached to 

 the tail-piece of the telescope by an elliptical base plate 10 mm. 

 thick, lateral flexure being guarded against by several inter- 

 mediate metal ribs. The slit has only one movable jaw, and 

 the whole can be rotated round the telescope axis, and the posi- 

 tion angle recorded to i' of arc. For comparison spectra the arc 

 light has been found most convenient, the difficulty of spectral 

 displacement of comparison lines due to imperfect adjustment 

 of source having been overcome by interposing a translucent 

 diffusing screen between the light and slit. The collimator 

 lens (Steinheil)has an aperture of 3 2 cm. ; focal length, 48 cm. 

 One of the camera objectives is a Zeiss anastigmat of 56 cm. 

 focus ; the other a triple cemented lens by Steinheil of 4'i cm. 

 aperture ; focus, 41 cm. The prisms are of very white Jena 

 glass, and with the Zeiss camera lens a spectrum of uniform 

 focus from b to K is obtained. Delicate arrangements have been 

 made for .securing constant temperature conditions, &c. The 

 weight of the complete spectrograph is 31 kilog. 



{b) Single-prism spectrogragh: — In this instrument the colli- 

 mator lens is 3-5 cm. aperture, focus 53 cm. ; the camera lens, 

 4 cm. aperture, locus 72 cm., both being triple cemented objec- 

 tives by Steinheil. The prism is by Zeiss, and has a refracting 

 angle of 60°, with faces 61 mm. long and 45 mm. high. The 

 spectrum is uniformly sharp from D to N. The whole instru- 

 ment weighs 20 kilograms. 



Prof. Vogel gives the results of the application of tests insti- 

 tuted by Prof. W. W. Campbell for the Mills' spectrograph of 

 the Lick Observatory, showing that the performance of both 

 instruments is very trustworthy. Three plates are given showing 

 the instruments in position as attached to the telescope. 



Structure and Constitution of Two New Meteor- 

 ites. — Messrs. G. P. Merrill and H. N. Stokes recently 

 communicated a paper to the Washington Academy of Sciences 

 {Proceedings, vol. ii. pp. 41-68, July 1900), describing the 

 results of their examination of two fragments of newly-fallen 

 meteorites. One, a stony meteorite, fell on July 10, 1899, in 

 Allegan, Michigan, U.S.A., the largest fragment weighing 

 62.^ lbs. To the unaided eye this stone shows on the broken 

 surfaQp a quite even granular structure of grey colour, and, on 

 closer examination, numerous beautifully spherulitic chondrules, 

 averaging not more than one or two millimetres in diameter. 

 In some cases these chondrules have pitted surfaces. More 

 critical inspection indicates that they are composed of enstatite 

 and olivine. Numerous brilliant metallic points of a silver-white 

 colour indicate the presence of disseminated iron, so that the 

 stone may be said to be made up of the chondrules, iron and dark 

 grey silicate minerals, imbedded in a light ashy grey matrix. 

 This Allegan stone is exceedingly friable. Microscopically, the 

 ground mass of the stone is seen to be made up of a confused 

 agglomerate of olivine and enstatite particles with interspersed 

 metallic iron, iron sulphide and chromic iron. An important 

 feature is that in no cases do the silicates occur with perfect 

 crystallographic outlines, both olivine and enstatite being frag- 

 mental. The presence of alumina and alkalis suggested a 

 search for felspar, but it was decided that this mineral was not 

 present. A considerable proportion of the ground mass was 

 lound microscopically to be composed of a black glassy material. 

 Careful chemical analysis showed that 77 per cent, of the 

 meteorite was of non-metallic origin, the remainder being chiefly 

 iron and nickel. The second meteorite examined is known as 

 the Mart Iron, having been found early in 1898 near Mart, in 

 Texas, This originally weighed 153 lbs., from which a slice 

 weighing 456 grams was presented to the National Museum at 

 Washington. The etched surface shows the iron to belong to 

 the octahedral variety, and is of moderately coarse crystallisation. 

 Chemical analysis showed that 98-3 percent, of the meteorite was 

 composed of the metals iron, nickel, copper, cobalt, the remainder 

 being made up of schreibersite and a small quantity of troilite. 



Photographs of both meteorites in their present condition are 

 given, and numerous drawings indicating the microscopical 

 structure. 



