472 



NATURE 



[October 13, 191*0 



the old conditions to deliver the water in an unliltorcd 

 state from the open service reservoirs to the town. '1 he 

 raw water is normally excellent, owing doubtless to the 

 underground chalk through which it passes, but discolora- 

 tion occasionally occurs during wet weather following a 

 period of drought. Ferro-concrete on the Hennebique 

 svstem has been employed largely on the new construc- 

 tional worlc. 



In this month's Aeronauiics appears an announcement 

 to the effect that, recognising the importance of flying 

 from a military point of view, that journal offers to 

 present a complete aeroplane to the first suitable officer 

 of the army who applies for it and is willing to try his 

 best to become proficient with it. 



In the article on " Mathematics in .Austria," in N.murk 

 of Septriiilii 1 j'l. Ill' niii.n w.i-; made of arithmetic papers 

 set by till' Civil Srrvitr Cunuiiisvioners and other examin- 

 ing bodies. The writer asks us to say that his allusion 

 to the Civil Service Commissioners was due to his belief 

 that they regulated the .^r'my Qualifying as well as the 

 Army Competitive examination. He has since found that 

 the former is.conducted by the " .^rmy Qualifying Board." 

 His reference, therefore, to the Civil .Service Commissioners 

 was incorrect. 



.\ TRANSLATION into German by Prof. Julius Ruska of 

 Prof. W. H. Hobbs's book on " Earthquakes " has been 

 published by .Messrs. Quelle and Meyer, of Leipzig, k 

 review of the original volume was published in the issue 

 of Nature for- March- 26, igdS .(vol. Ixxvii., p. 4.S1). The 

 price of the German work is 6.60 marks. 



' OVR ASTRONOMICAL COLUMN. 



.Announcement, of a Nova. — .\ circular received fro.n 

 the KielCentralstelle states that in a telegram from Cam- 

 bridge, Mass., received on October 5, it is announced 

 that a new star in Sagittarius has been discovered by 

 Mrs. Fleming on a plate taken on May 31-831 (G.M.T.). 

 This object, Nova Sagittarii No. 2, was then bright 

 enough to be- visible in a small telescope, and its position 

 is a=iyh. 52m. 15s., 5 = 27°- 32-2' south, about 7m. west 

 and 3° north of the, third-magnitude star 7 Sagittarii ; like 

 most other objects of ' its class, this nova lies in, or very 

 near to, the Milky Way. , ■ 



It is interesting to i-ecair that -Nova Sagittarii No. i 

 was also discovered -by- Mrs. -Fleming on, a photograph 

 taken at Arequipa on March- 8, 1898, but. was not, detected 

 until March, 1899. 



Time of the Solar Transit of Halley's Comet. — The 

 examination of various solar photographs for traces of 

 Halley's comet during its transit of the aplar disc on 

 Mav 18 has hitherto been somewhat indefinite, because 

 the' exact times of ingress and egress were not certainly 

 known. Figures which should permit of more definitive 

 examinations are now given in No. 616 of the .lstrono»in-at 

 Journal ; they are as follows : — 



n.M.T. 

 h. m. 



Ingress 15 4° ■•■ Angle 279° _^ 



Least distance between centres . 16 9 ... Comet 3' 15" N. 

 Egress 1639 ■■• Angle 76° 



Observ.^tions of Comet loioa. — In a Bulletin of the 

 Catania .Academy of Natural Science, just received, Prof. 

 Ricco discusses the observations of comet iqioa, visual, 

 photographic, and spectroscopic, made at the Catania 

 Observatory during January and February. After describ- 

 ing the visual and spectroscopic results. Prof. Ricc6 

 directs special attention to the greater similarity of the 

 visual and photographic images in this comet than in 

 s -veral which immediatelv preceded it, due to the greater 

 proportion of vellow radiations. He also suggests that 

 the appearance of the three " hydrocarbon " and one yellow 

 band, when the comet was near perihelion, is in accord- 



ance wi,!i Hassellberg's experiment with a (jeis-,-;ler tube 

 containing hydrocarbon and sodium vapours. With the 

 tube cool, only the hydrocarbon bands showed in the 

 spectrum, but when it was heated the sodium band was 

 seen to be relatively strong. 



It is stated in the Observatory (No. 4271 that whilst 

 the object observed by M. Sykora (Nature. September 8, 

 p. 322) was in the right position-angle, it was considerably 

 too far from the centre of the disc. 



.Arabian Astronomical Instruments. — Vol. xli. (1009) of 

 the Siizungsberichte der Physikalisch-Mcdizinischcn Hozieldt 

 in Erlangen contains No. iS of Prof. E. Wiedemann's con- 

 tributions to the history of science, which deals with some 

 of the astronomical instruments of the .Arabs (53 pp.). 

 Chapter i. gives descriptions of the astrolabe and the quad- 

 rant, founded on two writings by .Al Biruni in the Royal 

 Library of Berlin. Chanter ii. gives a review of the trig- 

 onometry of the Arabs and its application to problems arising 

 from the use of the gnomon (" determin.ation of the shadow "). 

 Chapter iii. contains an account (chiefly from Al Biruni) 

 of the use of the astrolabe in surveying. The paper is of 

 special interest on account of the many extracts it gives 

 from unpublished manuscripts, and makes us hope that some 

 further details may yet be brought to light about the in- 

 struments used in the great observatories at Cairo, Mcragha 

 and elsewhere, as to which our knowledge is very im- 

 perfect. 



New Ephemerides for Saturn, Uranus, and Neptune. 

 — For some time it has been a known fact that the 

 observed positions of the three outermost planets showed 

 considerable discordance with Leverrier's tables. In 

 No. 427 of the Observatory Dr. Downing directs attention 

 to the advance made by the compilers of the Connaissance 

 des Temps in publishing, for 1912, ephemerides based on 

 (iaillot's " Tables Rectifi^es " instead of Leverrier's tables. 

 .A comparison of the respective corrections shows that an 

 important step in advance, in the calculation of accurate 

 ephemerides of the major planets, has been made. 



Irregularities in the Motion of .Algol's Satellite. — 

 In the October number of the Bulletin de la Society 

 astronnmique de France M. Enzo Mora shows that, 

 according to observations made in iqo8, iqoq, and iqio, 

 the relative motion of the satellite of .Algol has been sub- 

 iect to an extraordinary perturbation. Comparisons made 

 between the brightness of .Algol and that of € Persei, 

 within about 40 minutes of the minimum of the former, 

 indicate departures from the normal of the time of mini- 

 mum ranging from to 26 minutes. The latter figure is 

 somewhat uncertain and unique, but the difference cannot be 

 traced to observ.ntional error; nrior to iqoo the departure 

 from normal had never exceeded 6 minutes. The pertur- 

 bative action of other satellites is suggested as a possible 

 cause of these irregularities. 



The Cambridge Observatory. — The annual report of 

 the work done at the Cambridge Observatory during the 

 Year ended Mav i.S is divided into two sections, in the 

 former of which Sir Robert Ball gives an account of the 

 general observations. From this we learn that the results 

 of the investigations into the constant of aberration and 

 the variation of latitude, made by Mr. Cookson during 

 iqo:;-7, are being prepared for press by Mr. Stratton, 

 while the manuscript pfiotographic catalogue of 6000 stars, 

 observed at eleven observatories during the Eros campaign, 

 has now been completed by Mr. Hinks. 



In the second part Prof. Newall describes the work done 

 in the astrophysical department. The radial velocities of 

 certain red stars, of which manv show" fluctuations of 

 brightness with long periods of variation, are being investi- 

 gated by Mr. Stratton. It is with regret that \ye_ note 

 that some difficulty is being experienced in obtaining a 

 perfect 12-inch objective, of (10 feet focal length, for use 

 in the solar observations. 



Obsf.rv;\tions of Neptune's Satellite. — The observa- 

 tions of Neptune's satellite, made by Prof. Barnard with 

 the 40-inch refractor durin.« iqoo-io. are published in 

 No. 617 of the Astronomiral Journal. .A magnifying power 

 of 700 was usually employed, but the satellite was fre- 

 quently found to be an extremely difficult object ; the 

 recorded magnitudes range from 13-0 to 14-5. 



NO. 2137, VOL. 84] 



