NATURE 



[August 23, 1900 



Little Cormorant {Phalacrocorax javanicus), a Green-winged 

 Dove {Chakophaps indica) from India, received in exchange ; a 

 Japanese Deer {Cervits sika), five Rosy-billed Ducks {Metopiana 

 peposaca), bred in the Gardens. 



OUR ASTRONOMICAL COLUMN 



Velocities of Meteors.— At the second annual meeting of 

 the Astronomical and Astrophysical Society of America, recently 

 held at Columbia University, New York, Dr. W. L. Elkin 

 described the apparatus and results of photographs obtained at 

 the Yale Observatory for the determination of the velocity of 

 meteors (Science, vol. xii. pp. 125-6). The idea of using photo- 

 graphy for this purpose appears to have been first suggested by 

 J. H. Lane in i860, but it was not until 1885 that Zenker made 

 the next practical attempt in Berlin, and attention has again 

 been recently called to the matter by Prof Fitzgerald. The 

 Yale apparatus consists of a bicycle wheel fitted with twelve 

 radial opaque screens, fixed so that, while rotating, the screens 

 are brought intermittently in front of the cameras. The wheel 

 as at present worked makes about 50-60 revolutions per minute, 

 but it would be better to increase this speed in future apparatus. A 

 check on the velocity is afforded by records made each revolution 

 on a chronograph. The length of interruption of the meteor 

 trail and the consequent velocity are then determinable if a 

 second observation of the meteor from a distant station has been 

 obtained. In November and December 1899, five such duplicate 

 trails were secured. The apparent velocities of the.se are given 

 as50'4, 12-2, 50'3, 20'2, 36-5 kilometres per sec; their altitudes 

 varying from 45 to 100 kilometres. Correcting the apparent 

 velocities for the attraction of the earth and the diurnal rotation 

 by Schiaparelli's formula;, the true velocities with respect to 

 the sun are 34 '4, 32 'o, 32-4, 39"8, 34'o kilometres per sec. 



Comparing these velocities with those calculated on assumption 

 of parabolic or elliptic orbits, the real velocities are in all cases 

 smaller, indicating that the atmospheric retardation has amounted 

 to 8-15 kilometres per sec. The elements deduced for one 

 meteor, an Andromedid, agree remarkably closely with those of 

 Biela's comet, showing the method to be capable of considerable 

 accuracy. 



Standards for Faint Stellar Magnitudes.— Prof 

 E. C. Pickering announced at the above-mentioned conference 

 that a grant of 500 dollars had been made from the Romford 

 Fund for the purpose of carrying out an investigation on the 

 brightness of faint stars by the co-operation of several observ- 

 atories possessing large telescopes. The point immediately 

 desirable is the accurate measurement of a few stars which shall 

 serve as standards for future work on a larger scale. Five 

 photometers have been constructed, each having a photographic 

 wedge which may be interposed between the eye and the star 

 as seen by the telescope. Thirty-six regions have been care- 

 fully selected in different parts of the sky, and twenty stars 

 (five of each of magnitudes 12, 15. 16, 17) are to be chosen in 

 each region, the faintest to be selected and measured with the 

 Lick and Yerkes telescopes. The stars of the i6th magnitude 

 will be measured with the 26-inch of the University of Virginia, 

 and perhaps also with the 23-inch Princeton refractor ; those 

 of the 15th magnitude will be measured by the 15-inch Harvard 

 telescope. All of these are to be then compared with stars of 

 the I2th magnitude, whose absohite magnitudes will finally be 

 determined with the 12-inch Harvard meridian photometer. 

 After the work is properly got in hand, it is hoped that it may 

 be reduced to a simple routine without sacrificing the quality 

 of the results. 



The Total Solar Eclipse, May 28, 1900.— As more 

 detailed reports of the results obtained by the American ob- 

 servers during the recent total eclipse come vo hand, it is interest- 

 ing to note the increased use which has been made of large 

 diffraction gratings, both concave and plane. In Science (vol. 

 xii. pp. 174-184), Mr. L. E. Jewell describes the work at Pine- 

 hurst, N.C., and Griffin, Georgia, of the two parties organised 

 by the physical department of the Johns Hopkins University. 

 At each station there were installed two spectro.scopes, one having 

 a plane diffraction grating, surface 3x5 inches, 15,006 lines to 

 the inch, used in conjunction with a quartz lens to photograph 

 the spectrum of the first order ; the other having a concave 

 grating of 10 feet radius and 15,000 lines to the inch, mounted 



NO. 1608, VOL. 62] 



in the usual Rowland form, with a large quartz lens to throw 

 an image of the sun on the slit-plate from a heliostat. The 

 photographs were very successful, and show the spectrum from 

 wave-lengths 3000 to 6000, even the exposures of only one 

 second giving good negatives. 



In the same number of Science Profs. E. B. Frost and E. E. 

 Barnard describe the apparatus they successfully used during 

 the same eclipse at Wadesboro, N.C. 



Report of the Cape Observatory.— In his report for 

 the year 1899 Sir David Gill, Her Majesty's Astronomer at the 

 Cape of Good Hope Observatory, makes special mention of the 

 completion of the new record room, providing storage for manu- 

 scripts, the safe preservation and orderly arrangement of the 

 precious astrographic plates, and also serving as the place where 

 the measurements of these plates are undertaken. 



The pier and foundations for the new transit circle are com- 

 pleted, but the delay in obtaining the sheet steel dome has kept 

 the work at a standstill. The observations with the transit 

 instrument have been mainly those of the standard stars for the 

 reduction of the Catalogue Astrographic plates.. When the new 

 transit circle arrives it will be entirely devoted to the systematic 

 meridian observations of the sun. Mercury, Venus and funda- 

 mental stars. With the heliometer, observations of all the 

 oppositions of major planets have been continued. 



The 24-inch object glass of the McClean equatorial was 

 returned to Sir Howard (irubb for refiguring, and this instru- 

 ment has hitherto only been used with a slit spectroscope for 

 stellar spectra. Since the photographic objective was dis- 

 mounted the 18-inch visual lens has been used for measurements 

 of twenty-one close double stars. The 7-inch equatorial has 

 been used in the revision of the Cape Photographic Durch- 

 musterung, in the observation of suspected variable stars, and ii> 

 the detection of double stars. 



The 6-inch instrument with a Zollner photometer has been 

 used for determining the visual magnitudes of stars in selected 

 areas of different galactic latitudes, the photographic magnitudes 

 of which are already determined. A comparison between the 

 visual and photographic magnitudes will subsequently be made. 

 With the astrographic equatorial 152 chart plates and 184 revision 

 cata/o^ue p]&tes have been passed. 103 plates, containing 38,785 

 stars, have been measured during the year, all observations 

 showing an error of o"-6 being repeated. 



Seventy-eight photographs ollris were taken during the period 

 July ii-December 31, with six exposures on each plate. In 

 conjunction with meridian observations of comparison stars, it is 

 intended to use the results of the measurements of these plates 

 for determining the mass of the moon. 



The geodetic survey of South Africa and Rhodesia has been 

 considerably advanced, but was interrupted by the outbreak of 

 the Transvaal war. The Anglo-German boundary survey has 

 been hindered by the waterless character of the Kalihari Desert, 

 but the work is now completed as far as Arahoab, from which an 

 offset chain will be carried to the 20th meridian. 



RousDON Observatory (Devon). — Sir C. E. Peek sends 

 a pamphlet of sixteen pages containing the sixth contribution of 

 systematic observations of variable stars made at his observatory 

 at Rousdon, Lyme Regis, Devonshire. The present report 

 furnishes the details of the variability of T Cassiopeins for the ten 

 years 1889- 1898, and of R Cassiopeise for the twelve years 

 1887-1898. The light curves of both stars are also plotted at 

 the end of the pamphlet. 



Independent Day Numbers for 1902. — A small pamphlet 

 has been issued from the Cape Observatory giving the indepen- 

 dent day numbers for correcting the places of stars given in the 

 Nautical Almanac for 1902. The values of the constants of 

 precession, aberration and nutation employed in these tables are 

 those recommended by the Paris International Conference of 

 1896. 



THE AUGUST PERSE IDS OF 1900. 

 QBSERVATIONS of this well-known annual display were 

 ^^^ much hindered by moonlight, though the weather was 

 generally clear at about the time of the maximum. Oilt 

 satellite was full on the evening of August 10, and obscured 

 all the smaller meteors. Apart, however, from this inter- 

 ference, the shower of 1900 seems to have been a somewhat 

 scanty one. It furnished a considerable number of large 



