February 22, 1912] 



NATURE 



565 



OVR ASTRONOMICAL COLUMN. 



The Nova, or Variable, 87.1911 Persei. — Photographs 

 of the region surrounding the questionable object recently 

 announced by Herr D'Esterre as a possible nova were 

 secured by Herren Miethe and Seegert, of Charlottenburg 

 photographic observatory, between January 12 and 16, and 

 are discussed in No. 4555 of the Astronomische Nach- 

 richten. Six photographs, showing images of fifteenth- 

 magnitude stars, exhibit no certain trace of the object, but 

 on two particularly good plates there appears, in the posi- 

 tion of D'Esterre's object, the trace of a nebulous, indefinite 

 image, which is probably connected with it. Further 

 observations are to be made. 



Observations of Jupiter. — Vol. iv. of the Recherches 

 astronomiques de I'Observatoire d' Utrecht is devoted to 

 the publication and discussion of the observations and draw- 

 ings of Jupiter made by Prof. Nijland during the period 

 1895-1906. In the first part, Prof. Nijland discusses 156 

 of the drawings in detail, giving a tabulated statement of 

 the conditions under which they were severally made, and 

 then directs attention to some of the general features re- 

 marked. Changes of colour of the several bands, spots, 

 and streaks were noted from time to time, and although 

 the material does not confirm the suggestion of periodicity 

 made by Mr. Stanley Williams, it does not contradict it. 



Part ii. deals with the spots, taking the observations 

 seriatim, and there are some interesting notes concerning 

 the variability of appearance — e.g. the white spots occasion- 

 ally seen on the Red Spot area — of these peculiar features. 

 In part iii. the Red Spot and its mutability are treated 

 specially, and the volume concludes with fine reproductions 

 of the 156 drawings of the planet. 



Photometric Observations of the Asteroids. — The 

 importance of determining the light of the asteroids, which 

 in several instances shows strange and puzzling variations, 

 is emphasised by Prof. E. C. Pickering in Circular 169 of 

 the Harvard College Observatory. 



To clarify matters, Prof. Pickering tabulates the photo- 

 metric measures made by different observers in seven series 

 of forty-three asteroids, and then discusses the differences 

 of the means from the calculated values given for the 

 magnitudes at mean opposition in the Berliner Jahrbttch. 

 He finds that the term o-2(«i„ — 9-0) gives the relation 

 between w„ (the Jahrbuch magnitude) and the mean of the 

 residuals obtained by subtracting the mean observed magni- 

 tudes from the computed magnitudes. The photometric 

 magnitudes corresponding to the values of m„ given in the 

 Jahrbuch, 7-0, 8-o, 9-0, lo-o, ii-o, 12-0, and 13-0, are shown 

 to be 6-6, 7-8, 9-0, 10-2, 11-4, 12-6, and 13-8, respectively. 



Prof. Pickering remarks on the convenience for photo- 

 metric observations of the ephemerides for the first four 

 asteroids given in the British Nautical Almanac, and 

 wishes that they should be extended to Eros and several 

 other special objects, also that they should include the 

 values of the phase angle. 



Observations of Comets. — Observations of several of 

 the comets of 1911 are reported in Nos. 4555-56 of the 

 Astronomische Nachrichtcn from Bothkamp, Vienna, 

 Utrecht, and Warsaw. 



Dr. Schiller gives positions and describes the appear- 

 ance of 19116, 1911C, 1911/, and igiJg, and shows in a 

 table of reduced magnitudes the probable oscillation of the 

 intrinsic brightness of comet 1911c (Brooks). Prof. 

 Holetschek gives measures of the brightness and the 

 diameters of comets 1911c, 1911/, and 1911^, while Herr 

 Tscherny gives places for, and describes the appearance of, 

 comets 1911C, 1911/, and 1911^^. On September 20, 1911, 

 an eleventh-magnitude star was easily visible through the 

 head of 1911c. 



Occultations of Mars and the Question of the 

 Existence of a Lunar Atmosphere. — During the occulta- 

 tion of Mars on December 4, 191 1, Prof. W. Luther, 

 observing with the refractor of the Dusseldorf Observatory, 

 saw the half of the planet's disc which was nearest to the 

 moon's limb become green, as though overcast by a 

 shadow, while the outer half was as bright as usual ; this 

 was at about i7h. 7m. 22s. (Dusseldorf M.T.). Looking 

 through his old observations, he found a note of a similar 

 phenomenon taking place on October i6, 1902, and suggests 

 that these observations indicate that there exists some 



material, extending to about 100 km. or more above the 

 moon's surface, which is capable of modifying, or absorb- 

 ing, light given out by a body passing behind it (.istro- 

 nomische Nachrichten, No. 4556). 



South African Meteorites. — A preliminary note on the 

 meteorites in the Bloemfontein Museum is contributed to 

 part iii., vol. ii., of the Transactions of the Royal Society 

 of South Africa by Mr. W. A. Douglas Rudge. 



There are in the museum three specimens, two of thenx 

 portions of the same fall, which occurred at Kroonstadt on 

 November 11, 1877, and the third a single mass which, 

 fell at Winburg in 1881. 



The larger of the twin fragments is very hard, yet easily 

 friable, so that sections could not be cut ; but by grind- 

 ing, a surface was exposed showing masses of malleable 

 nickel-iron set in a matrix of hard stone. The specific 

 gravity was found to be 3-54, and that the mass was 

 porous was shown by the fact that the weight in water 

 increased from 989-5 to 991-4 grams after an hour's 

 immersion. Qualitative analysis revealed the presence of 

 iron, nickel, aluminium, calcium, silicon, sulphur, and 

 traces of manganese, but no carbonic acid. A preliminary 

 quantitative analysis gave : — insoluble matter 54-68, iron 

 30-38, and nickel 13-21 per cent. 



The Winburg meteorite is very peculiar in having veins- 

 of lustrous iron-nickel alloy running through its mass of 

 otherwise nearly pure iron. The general mass is very 

 soft, but the crystals are harder and much brighter. The 

 weight of the whole is about 50 kilograms, but there is 

 evidence that it is only a portion of a larger mass. The 

 preliminary analysis gives : — iron soluble in dilute H^SO^, 

 92-32 per cent. ; iron in crystals, 2-35 per cent. ; nickel in 

 crystals, 2-00 per cent. ; and carbon and earthy matter^ 

 0-3 per cent. It would thus appear that practically all the 

 nickel is concentrated in the bright crystalline material 

 forming the veins. 



ASTROPHYSICS IN CANADA^ 



'T*HE general report presented by the chief astronomer 



-^ of the Dominion of Canada, Mr. W. F. King, gives 



detailed reports of progress made in the departments of 



time service, astrophysics, and geophysics. 



Meridian Circle and Time Service. — The installation of 

 this instrument has been attended with many unusual 

 difticulties. Considerable trouble was experienced with the 

 foundations of the meridian circle room owing to the perco- 

 lation of surface water. A partial remedy was foimd by 

 constructing a reservoir of 1200 gallons capacity, but as 

 this was still insufficient during heavy rain, the pier foot- 

 ings becoming waterlogged, a system of drains surround- 

 ing the outside walls would seem to be necessary. Pro- 

 vision has been made in the collimator piers for under- 

 ground lenses as permanent marks, similar to the system 

 which has proved so satisfactory at the Cape Observatory. 



The observers appea- to have also had a most unusual 

 experience with the transit circle itself. The graduated 

 circles were not adjusted properly on their seatings ; the 

 axis pivots were found to be made of comparatively soft 

 metal, rendering it necessary to shrink on collars of 

 hardened steel and rework the surfaces with the lathe at 

 the Royal Mint workshop. 



Astrophysics. — The principal work in the astrophysical 

 division has been the spectroscopic observations of radial 

 velocities of binaries, determined from photographic spectra 

 taken with the prism spectrograph. Five orbits have been 

 thus investigated, »j Bootis, Aquilae, o Corona; Borealis, 

 e Herculis, /3 Orionis. In other systems variable veloci- 

 ties have been discovered. Detailed records are included" 

 of measures of the spectrograms of the above stars, with 

 the individual velocities from each plate. 



A new single-prism spectrograph fm r.ulial velocity 

 work has been designed and constructed with a strain-free 

 mounting similar to that at the Lick Observatory. The 

 body of the instrument is supported at two points, with a 

 balanced action on a third, and the system is so successful 

 that it is stated the flexure is inappreciable when the 

 spectrograph is turned through 180°. 



Considerable time has been spent in testing the various 



1 Report of the Chief Astronomer, Ottawa, for the year ending March 3:, 

 1909. Department of the Interior, Sessional Paper No. 25<i. (1910.) 



NO. 2208, VOL. 88] 



