460 



NATURE 



[October 5, 191 1 



OUR ASTRONOMICAL COLUMN. 



Discovery of a Third-magnitude Comet (191 ig). — Yet 

 another object is added to the list of recently discovered 

 comets. On September 28 M. Beljawsky, at the Simeis 

 Observatory, saw a third-magnitude comet, of which the 

 position at 17b. 8m. (Simeis M.T.) was 



R.A. ioh. 43m., dec. 8° 15' N. 



This position lies in Leo, about half-way between x and 

 p Leonis, and rises just before dawn. 



A further observation, secured by Dr. Stromgren at 

 Copenhagen on September 29. iyh. 127m. (Copenhagen 

 M.T.), gave the position of the new comet as 



R.A. = ioh. 52m., 59-8s., dec. =8° 57' 49" N. 



According to telegrams published in The Daily Mail, this 

 object was observed at the Greenwich Observatory at 

 ibh. 30m. on Monday morning ; it has a very bright tail, 

 which shows up well on the photographs. At the same 

 hour on Sunday morning it was seen at the Royal Observa- 

 tory, Edinburgh, and its magnitude, soon after rising, was 

 estimated as 3.0. The observers there describe the tail as 

 curved and fan-shaped, and state that it could be traced 

 for a distance of 2°. 



Beljawsky 's comet is the seventh comet to be discovered 

 this year, and so will take the designation 191 1£. 



Brooks's Comet, 1911c. — Brooks's comet is now an 

 object of general interest, and in a clear atmosphere shows 

 a tail even to the naked eye ; on Sunday last, at Gunners- 

 bury, with a pair of ordinary opera-glasses, there was no 

 difficulty in seeing a filmy appendage, which stretched for 

 some 2 or 3 in a north-easterly direction. 



Writing from Malta on September 20, Mr. C. Leach said 

 the comet had been visible to the naked eye for some time, 

 but no tail was seen until September 16 ; on the two 

 succeeding nights he saw, without optical aid, some 3° or 

 4 of tail quite easily, and concluded that its brightness was 

 increasing. 



A number of observations are recorded in No. 4526 of 

 the Astronomische Nachrichten. Prof. Nijland publishes 

 some measures of magnitudes which suggest an oscillation 

 in the brightness of the comet, and M. Esclangon records 

 the phenomena observed during the occultation of a 

 105-magnitude star by the comet on August 17. From 

 ioh. im. os. to ioh. im. 12s. (Bordeaux M.T.) he was 

 unable to separate the star from the well-defined but slightly 

 fainter stellar nucleus of the comet. Although he could 

 detect no change of brightness while the star was passing 

 through the nebulosity forming the coma, he noticed a 

 distinct diminution of the star's light as it passed behind 

 the nucleus. 



Quenisset's Comet, 1911/- — Several observations of 

 comet 1911/ appear in No. 4526 of the Astronomische 

 Nachrichten, where the discoverer and M. Baldet describe 

 the object as being of magnitude 7-5, round in form, 

 having a nucleus, and showing the hydrocarbon-cyanogen 

 spectrum. 



In the Comptes rendus for September 25 they give 

 further details of the discovery, and briefly describe their 

 photographs. Short exposures (34 mins.) on September 23 

 showi d a round head and traces of a tail, while the spectro- 

 grams showed the blue band of the " Swan" spectrum 

 and the cyanogen band at A 388. On September 24 

 exposures of 2h. 9m. were possible, and a tail 1° long, in 

 position angle 322 , was clearly visible on the direct photo- 

 graphs ; the comet was sensibly brighter, and was suspei ti 'I 

 to be visible to the naked eye, its estimated magnitude 

 then being 6-5. The spectrum was much denser, and in 

 addition to the bands showed a fairly strong continuous 

 radiation. 



A set of elements and an ephemeris, based on observa- 

 tions made on September 24, 25, and 26, are published 

 by Dr. Ebell in a supplement to No. 4527 of the Astro- 

 nomische Nachrichten. The elements give November 12 

 as the time of perihelion passage, and the following is 

 taken from the ephemeris: — 



NO. 2l88, VOL. 87] 



Ephemeris 12/1. [M.T. Berlin). 



. (irue) 



8 (true) 



log. 



1. . 



Oct. 4 ... 15 207 ... +52 30-5 ... 0-0304 ... 99839 ... 67 



,, s ... 15 22S ... +50 35-6 



„ 6 ... 15 247 ... ^4S 429 



,, 7 ... 15 264 ... +46 52-6 



,, S ... 15 28 ... +45 4-8 ... 0-0103 ... 0'0026 ... 67 



,, 9 ... 15 294 ... +43 19-6 



,, 10 ... 15 307 ... +41 369 



,, 11 ... 15 320 ... +39 56-8 



„ 12 ... 15 331 ... +38 19-3 ... 9-9903 ... 00252 ... 67 



,, 13 ... 15 342 . +36 44-4 



Calcium Vapour in hie Sol.ik Atmosphere. — Continuing 

 his discussion of Mount Wilson observations of the move- 

 ments and condition of calcium vapour over sun-spots and 

 other special regions of the solar surface, Mr. C E. St. 

 John arrives at some valuable conclusions regarding the 

 conditions obtaining in the solar atmosphere, in No. 2, 

 vol. xxxiv., of The Astrophysical Journal ; only a very 

 brief summary of the principal results can be given here. 

 In most sun-spots the calcium vapour is descending at from 

 o-68 to 2-2 km. per second, but over the penumbra? that 

 vapour which produces the bright K„ line appears to be in 

 vertical equilibrium. Over flocculi a very doubtful upward 

 motion of this emitting vapour is suggested, but in both 

 cases the absorbing vapour descends as it does over the 

 general disc. Both absorbing and emitting vapours appear 

 to participate in the occasionally occurring rotary motion 

 around spot umbras, but the former have the greater 

 velocity ; this is also true for the inward radial motion of 

 vapour across the penumbras, and the combinations of the 

 two produce the vortical motions converging on the umbra. 

 Large masses of relatively cool calcium vapour high above 

 the chromosphere, that is to say, projected promin* 1 

 held responsible for the abnormal absorption line sometimes 

 splitting or bordering the K, bright lines. In addition to 

 the general circulation, there appear to be local systems in 

 which emitting vapour rises around the flocculi, and, flow- 

 ing across the penumbra, descends into the umbra of the 

 spot. The apparent changes of intensity in the bright Rl 

 line, at the sun's centre and limb, is shown to be probably 

 no more than a contrast effect. The differences and 

 changes in the intensities of the K,, K„, and K, lines, and 

 hence the different results obtained for various levels in the 

 sun's atmosphere, find a possible explanation in the modifi- 

 cations of the radiation coefficients by several agencies. 



Elements and Designations for Recently Discovered 

 Minor Planets. — The usual list of elements and numbers 

 for minor planets recently discovered is published by Dr. 

 Cohn, of the Berlin Astronomisches Rechen-Institut. in No. 

 4521 of the Astronomische Nachrichten. It includes 

 twenty-three asteroids discovered in 1909, 1910, and 1011 at 

 the Konigstuhl, Taunton, Vienna, and Teramo Observa- 

 tories, and the final number given is 714. 



The Masses of Spectroscopic Binaries. — An interesting 

 paper in which Dr. Ludendorff discusses generally the 

 masses of different classes of spectroscopic binary stars 

 appears in No. 4520 of the Astronomische Nachrichten. 

 Inter alia, he shows, from the study of twenty-five binaries 

 of the spectral classes Oe5 to BS, that they ha 

 bined masses two or three times as great as have the 

 twenty-six systems of classes A to K stars which he con- 

 sidered. 



Publications of the U.S. Naval Observatory. — A 

 number of works recently received from the U.S. Naval 

 Observatory includes the following : — Vol. vi. of the 

 Publications describes the equatorial observations of the 

 satellites of the major planets, made during the period 

 1893-1907. It also contains a number of miscellaneous 

 observations, an account of the transit of Mercury observa- 

 tions in 1S94, and a list of the Naval Observatory publica- 

 tions. In the introduction to the part dealing with the 

 equatorial observations there are some excellent plate 

 illustrations of the various instruments employed. Vol. 

 vii. is a catalogue of 23,521 stars in the Washington zones 

 for which the observations were made in 1846-52, and are 

 redui e'd 10 epoch 1850. 



