December 8, 1904J 



NA TURE 



m 



amount of detail given concerning the careers of the notabili- 

 ties included, and something- might be done with advantage 

 to reduce the lengths of some of the biographies, and thus 

 to keep the volume of a convenient size. The " Who's 

 Who Yearbook " contains the tables which were formerly 

 included in " Who's Who " itself. " The Englishwoman's 

 Yearbook " will in its revised form continue to lighten the 

 labours of women sharing in the useful work of the world. 



OUR ASTRONOMICAL COLUMN. 



Re-discovery of Tempel's Second Comet. — A telegram 

 from the Kiel Centralstelle announces that Tempel's second 

 comet was re-discovered by M. Gavelle at Nice on 

 November 30, and that the observation showed the daily 

 ephemeris published in No. 3971 of the Asironomisclie 

 Nachrichtcn to be nearly correct. 



The following is an e.xtract from the above named 

 ephemeris, which was published by M. J. Coniel : — 

 12;;. M.T. Paris. 



Parall.ax OF A Low Meteor. — Whilst exposing on the 

 Andromeda nebula with two Voigtlander objectives on 

 August 12 Herr P. Gotz, of Heidelberg, photographed on 

 each plate the trail of a remarkably low Perseid. From 

 measurements of the trail on the two plates it was possible 

 to determine the parallax of the meteor at definite points 

 in its flight where the trail was considerably strengthened. 

 The result showed a mean parallax of 28"- 12, whilst for 

 six distinct points on the trail the following parallaxes were 

 determined : — 



2S"-26, 37"'3i, 2y"-yS, 25"-2o, i7"-i4, io"-o. 



The base of the triangle Meteor — Voigtlander I. — \'oigt- 

 lander II. measured 68 cm., and it therefore follows that 

 the distance of the meteor at each of these points was 

 498, 378, 505, 5-57, 8-27, 1403 kilometres respectively, 

 the coordinates of the meteor at each point being re- 

 spectively : — 

 a = oh. 28 -201., oh. 22m., oh. i9-2m., oh. l6-Sm., oh. io-7m., 



oh. 7-7m. 

 5= -1-43° 13', +42" i', -1-41° 28', -f40°58', -1-39° 47', 



+ 38° 59'- 



The path of the meteor was apparently rectilinear, but 

 the observations indicated 'that it described a sharp curve 

 in the third dimension with the convex side towards the 

 observer. 



The path of the meteor extended from a = oh. 33-6m., 

 5= -1-44° 17' to a = 23h. 52.2m., 8= +35° 28' (Astronomische 

 Nachrichten, No. 3975). 



Date of the Most Recent Sun-spot Minimum. — From a 

 discussion of the observations of solar phenomena made at 

 the Roman College Observatory during the period 

 November 25, 1900, to January 4, 1902, Signer E. Tringali 

 deduces the date of the latest sun-spot minimum to have 

 been June 15, 1901, or 1901-45. 



In Table i. of the communication the relative daily fre- 

 quencies of spots, &c., are given for the years 1878-9 and 

 1888-1903, and it is seen that the frequency of days without 

 spots during 1901 was greater than obtained during the 

 previous minimum {1S89), but less than in the 1878 

 minimum. The numbers given for 1878 and 1901 are 0.76 

 and 073 respectively {Memorie della Societa degli Spettro- 

 scopisti Italiani, No. 8, vol. xxxiii.). 



Observations of Perseids, 1904. — In No. 9, vol. xxxiii., 

 of the Memorie della Societa degli Spettroscopisti Italiani, 

 Prof. S. Zammarchi, director of the meteorological observ- 

 atory at Brescia, gives in tabular form the results of the 

 observations of Perseids made at that observatory during the 

 nights of August 9-14. 



NO. 1832, VOL. 71] 



531 Perseids were seen, and the observations are recorded 

 in the order of the appearance of the objects, the time, the 

 points of appearance and disappearance, and the general 

 characteristics of each meteor being given. 



The Orbit of Sirius. — In No. 3981 of the Astronomische 

 Nachrichten Prof. Doberck gives the results of a discussion 

 of the observations of Sirius and its faint companion, and 

 includes a set of elements," an ephemeris for the period 

 1903-2-1917 2, and a table showing the differences between 

 the observed and calculated values of position angle and 

 distance. Owing to the great difference between the magni- 

 tudes of the two components, the systematic errors of 

 observation are unusually large. 



The following are the elements determined from the dis- 

 cussion : — 



jj=225°49' P- 49 49 years 



\ = 29° 54' T= 1894-28 



y = 43° 20' o=7"-5i3 



e =0-5871 



The orbit is referred to the equinox of 1900. The motion 

 is retrograde, and the anomalies are considered as positive 

 before and negative after periastron. 



The consideration of the errors of observation shows 

 that they are inversely proportional to the aperture of the 

 object glass employed. 



Harvard Observ.itions of Variable Stars. — Part ii., 

 vol. xlvi., of the Harvard College Observatory Annals is 

 devoted to the observations, chiefly of variable stars, made 

 by Prof. E. C. Pickering with the meridian photometer 

 during the years 1892-8. 



The first chapter gives the results of the observations of 

 short-period variables, and then discusses the phases of the 

 light-variations and the corrections to their ephemerides. 

 Chapter ii. deals similarly with the observations of variables 

 of the Algol type, chapter iii. collates the observations of 

 various miscellaneous objects, and the fourth chapter gives, 

 and discusses, the observations of planets and asteroids. 

 The early observations of variable stars, at Harvard, are 

 collected into tables in the fifth chapter, whilst the last 

 chapter discusses the observations of long-period variables, 

 and describes the eight light-curves given on the two plates 

 at the end of the volume. 



Correction of the Longer Term in the Polar Motion. 

 — In a previous communication to the Astronomische Nach- 

 richten Mr. Kimura, of the Mizusawa International Lati- 

 tude Station, showed that the cycle of the polar motion 

 might be approximately represented by two principal terms 

 of 365 and 438 days. 



In No. 3981 of the same journal, however, he discusses 

 the latter term more fully, from observations made during 

 the period 1890-1904, and finds that it is probably a day 

 or two too long. Taking the two periods 1890-1896 and 

 1896— 1902, he derived the value 437- 1 days, whilst from the 

 periods 1892-1898 and 1898-1904 the value 436-6 days was 

 obtained. The latter value, Mr. Kimura thinks, is likely 

 to be the more correct, and consequently the cycle is not 

 exactly six years as was indicated by the former discussion. 



The values given in the paper show that for the years 

 1890 and 1891 the radius of the circular motion was 

 especially large, but from 1892 to last year it remained 

 nearly constant. 



Arc Spectra of the Alkali Metals. — In No. 9, vol. xl., 

 of the Proceedings of the American Academy of Arts and 

 Sciences Mr. F. A. Saunders, of Syracuse University, gives 

 the results of a series of researches on the arc spectra of 

 lithium, sodium, potassium, rubidium, and ca;sium. 



The salts were vaporised on nearly pure carbon poles, and 

 the spectra were taken with a grating camera, special 

 arrangements being made to photograph the spectra well 

 up into the red. 



Several new lines, which fit into the respective series, 

 were discovered, and in the lithium spectrum Mr. Saunders 

 believes that the dual character of the lines is real and not 

 simply due to reversals as has been supposed by Hagenbach 

 and other spectroscopists. 



A comparison of the arc spectra with spark spectra of 

 the same substances showed no relative enhancement of 

 any of the lines in passing from the conditions of the arc 

 to those of the spark. 



