(48 



NATURE 



[January 12, 191 i 



OVR ASTRONOMICAL COLUMN. 



The January Meteors. — Mr. W. F. Denning writes : — 

 " The night when the shower of Quadranlids or Bootids 

 was expected proved very clear at Bristol and many other 

 places. The display of meteors was not a very abundant 

 •one, but what the event lacked in numbers was amply 

 ■compensated for by the brilliancy of the objects observed. 



" Not only were the meteors generally very conspicuous, 

 but they traversed long tracks of the heavens, and their 

 flights were readily traced back to the visual radiant. 

 This year I made the centre at 227° + 54° from about 

 •eight paths, and there seemed another well-defined shower 

 of similar meteors from 250° + 47° in Draco. 



" The meteors were of moderate speed and accompanied 

 by trains. They were also well observed bv Miss Helen 

 M. Metcalfe, of Kildare, Mr. W. H. Steavenson, of 

 ■Cheltenham, and others. No doubt some of the larger 

 members of the shower were recorded at several stations, 

 and it is hoped that observers will send in their notes so 

 that the heights and velocities may be computed. January 

 is a good month for large meteoric fireballs, and it re- 

 mains to be seen whether the last half of the present 

 month will provide the usual number seen in preceding 

 years." 



Nova Lacert^. — The weather conditions, in London at 

 any rate, have not been favourable for observations of the 

 new star discovered by the Rev. T. E. Espin on December 

 30, J910. 



According to observations recorded in the Times, Mr. 



Chart showing position of Nova Lacertae. 



Hinks examined the nova on January i and 2, and found 

 it fainter on the second, night ; a bright line in the red, 

 the C line of hydrogen, was apparently the strongest in 

 the spectrum, and three other bright lines were observed. 



Mr. Espin, writing to the Observatory (January, No. 

 431), states that a further examination, on January i, 

 confirmed his previous observation of the spectrum ; it is 

 neither type iii. nor iv. Two bright lines are conspicuous, 

 the stronger one probably F, and a yellow line, which he 

 suggests is D3. Three bands appear between F and D, 

 and on the more refrangible side of F there is a band so 

 strong as to make the spectrum appear discontinuous ; 

 beyond that there is a bright band. The spectrum re- 

 minds Mr. Espin of that of R Cygni, with the details 

 more pronounced. He suggests that the star may turn 

 out to be a variable, although, if so, it is curious that it 

 has not been discovered, as have several others in the 

 neighbourhood, at the Harvard Observatory. 



A Daily Mail report states that no spectrum observa- 

 tions have been possible at Greenwich, owing to the bad 

 weather, but photographs, which show the nova to be 

 decreasing in brightness, have been secured. The 

 Astronomer Royal expresses the opinion that the object is 

 reallj' a nova, not merely a previously undiscovered 

 variable star. 



NO. 2150, VOL. 85] 



The nova is conspicuous among the stars near by bv 



reason of its distinctly red colour. We append a chart 



showing its position relative to the bright stars of 

 Cassiopeia, Cepheus, and Lacerta. 



Comets Due to Return in 191 i. — Mr. Lynn's annual 

 note of the periodical comets due to return this year 

 appears in No. 431 of the Observatory . He includes 

 Brooks's 1889 comet, as it was due at perihelion on 

 January 8, but suggests that no further observations of it 

 at this return are likely ; it was nearest the earth on 

 August 9, 1910. 



Faye|s comet, in accordance with Prof. Stromgren's 

 conclusion as to the acceleration of its perihelion passage, 

 returned in 1910, and observations have been recorded in 

 these columns. 



Encke's comet is due in the coming summer, but Mr. 

 Lynn, considering its faintness in 1908, fears that we ar< 

 losing this well-known object, first observed in 1786. 



Wolf's comet, of 1884, is not due until early in 1912, 

 but observations may be secured about the end of th 

 present year. 



Preliminary Results derived from Radial-velocity 

 Determinations. — At the Boston meeting of the Astro- 

 nomical and Astrophysical Society of America Prof. 

 Campbell read a paper in which he gave the preliminarv 

 results derived from the study of 1073 radial-velocity 

 values. 



The position of the solar apex comes out as A = 272-0° + 

 2-5°, D=: -I- 27-5° ±3-0°, and the corresponding velocity o 

 the solar motion was found to b- 

 17-8 km. This latter value is lower 

 than those previously found, bui 

 the available data will yield nr. 

 higher .value. Apparently there i- 

 a difference depending upon th' 

 spectral type of the stars considered 

 for, taking 330 stars of types O-F.,. 

 V was found to be 17-7 km., whilst 

 704 stars of types F^-G, K and M 

 yielded i8-o km. 



Further, the radial velocities of 

 stars freed from the solar motion 

 component do not appear to be r. 

 function of the visual magnitude;?. 

 Stars of the later spectral types — as 

 divided above — appear to have radial 

 velocities nearly 50 per cent, greater 

 than those of the earlier types ; th' 

 increase is progressive. The mean 

 velocity for thirteen nebulae con- 

 sidered is 23-4 km. The results also 

 confirm Kapteyn's theory of a 

 systematic drift. 



In making the observed radial 

 velocities and the proper motions to 

 correspond, it was indicated (i) that 

 the stars of different magnitudes are less differentiated ir 

 distance than has hitherto been supposed ; (2) all th 

 brighter stars down to the fifth magnitude are further 

 away than indicated by the formulae for mean parallaxes ; 

 (3) the parallax stars which have been used as sample stars 

 are not representative of the stars in general. Some c> 

 these results may be modified by the proposed solution, 

 using Boss's proper motions now available. 



Other results accruing from the systematic study of 

 radial velocities indicate that, in general, the periods of 

 revolution are shorter for the early than for the late: 

 types ; the orbits also show less eccentricity. Sevent\ 

 orbits, now known with reasonable certainty, are in accord 

 with the theoretical conclusions of Darwin, Poincar^, and 

 See regarding the origin and development of binary stellar 

 systems (Journal R.A.S. Canada, vol. iv., No. 5). 



Stell..\r Magnitudes. — A popular and very interesting 

 paper on stellar magnitudes is published by Mr. J. E. 

 Maybee in No. 5, vol. iv., of the Journal of the Roya! 

 Astronomical Society (Canada). Mr. Maybee explains th' 

 system of magnitudes, tells how they are determined, ann 

 discusses some of the interesting facts which have accrued 

 from photometrical studies of the stars. 



.A.stronomical students and amateurs will probably find 

 a great deal of useful information in the paper. 



