NATURE 



[July 28, 1904 



OVR ASTRONOMICAL COLUMN. 



Astronomical Occurrences in August :— 

 Aug. 7. Juno in opposition to the Sun (Juno, mag. 87). 

 10. 7h. Saturn in opposition to the Sun. 

 10-12. Epoch of the August meteors (Perseids, Radiant 



45' + 57°)- 



14. iih. 20m. Minimum of Algol (B Persei). 



15. Venus. Illuminated portion of disc = o-983, of Mars = 



0-986. 

 17. Saturn. Outer major axis of outer ring = 43" '43. Outer 



minor axis of outer ring = 1 1 '37. 

 19. r6h. Mercury at greatest elongation (27° 24' E.). 



23. ilh. 6m. to I2h. 33m. Transit of Jupiter's Sat. III. 



(Ganymede). 



24. 8h. Moon in conjunction with Saturn (Saturn 4° 4' 



S-)- c , 



30. 8h. Moon in conjunction with Jupiter (Jupiter 2 7 



N.). 

 „ I4h. 44m. to i6h. Sm. Transit of Jupiter's Sat. III. 



(Ganymede). 

 , I4h. 51m. to l6h. 13m. Moon occults |' Ceti (Mag. 

 4-5)- 

 The Centenary of DorPLER. — We have received from Dr. 

 Karl Haas a copy of the address that he read on the occasion 

 of the celebration of the centenary of the birth of Christian 

 Doppler. It is strange to reflect that Doppler, in 1842, 

 years before Kirchhoff and Bunsen had demonstrated the 

 ipossibilities of the spectroscope, first announced the principle 

 bearing his name which has since become so famous and 

 so fruitful of application. He himself was not happy in 

 his original suggestion, for he sought to employ the 

 " principle " as a means of explaining the colour of double 

 stars, and it may be that some of the controversy that at 

 one time raged round this question originated in its faulty 

 application, rather than in the generic principle underlying 

 the suggestion. So far as acoustical waves were concerned 

 the matter could be, and was, settled by experiment, and 

 Dr. Haas not only referred to the various tests that had 

 been made to prove the validity of the "principle," but 

 exhibited some of the apparatus that had been employed, 

 and repeated the experiments. Dr. Haas briefly referred to 

 Doppler's strenuous life and work in other departments of 

 natural science, showing that the enunciation of the 

 principle was not a matter of accident, but that it was led 

 up to by philosophical study, and put before the audience 

 the grounds on which Doppler was entitled to their respect. 

 But the valuable work that had been accomplished in the 

 realm of spectroscopy naturally made him linger on this 

 part of the subject, and he gave a useful summary of what 

 has been effected by those who saw how the principle could 

 be applied in special directions ; as, for example, Sir William 

 Huggins in the measurement of the motion of stars in the 

 line of sight, Sir Norman Lockyer in the matter of sun- 

 spots and prominences, Dr. Langley and others in the 

 determination of the time of rotation of sun and planets, 

 Prof. Keeler in the spectroscopic observations of the ring 

 of Saturn, and by Dr. Vogel in the department of spectro- 

 scopic binaries. M. Belopolsky's scheme for showing ex- 

 perimentally the validity of the principle when applied to 

 light waves was mentioned, while in the depaitment of 

 theoretical physics one was reminded how the application 

 of the same principle was rendering most efficient service. 

 If the centenary served no other purpose, it at least had 

 the effect of tracing the connection between the original 

 thought and its manifold applications. 



S.^turn's Ninth S.atellite (Phcebe). — The next volume of 

 the " Harvard Annals " is to contain a discussion of Prof. 

 W. H. Pickering's recent observatons of the satellite 

 Phoebe from the photographs obtained at Arequipa. 



Meanwhile, in order that other workers may be able to 

 observe this satellite. Prof. E. C. Pickering publishes the 

 following position angles and distances from Saturn on the 

 dates named : — 



July 14 .. 

 July 24 .. 

 August 3 



Positic 



nsle 



Dis 



- 77-4 i7'-8 



••• 79°S i4'.3 



... 84''o lo's 



(Circular No. 67, Kiel Centralstelle.) 



NO. 1813, VOL. 70] 



PRiNcip.'iL Planes of the Stars. — In the first of a series 

 of papers entitled " Contributions to Stellar Statistics " 

 (published by the Carnegie Institution), Prof. Newcomb dis- 

 cusses " the position of the galactic and other planes 

 toward which the stars tend to crowd." 



After demonstrating in extenso the formation of the 

 general equation determining the planes, he considers 

 several special cases, and arrives at the following important 

 results, giving the positions of the poles of the respective 

 planes determined : — 



R.A. Dec. 



Galactic plane (omitting branch) ... 



,, ,, (including ,, ) ... 



Gould's belt (as determined from 36 



stars, of small proper motion, 



near it) 



Plane of all stars to magnitude 2-5. 



3-5- 



Plane of fifth-type (Wolf-Rayci) 



stars 



192S 

 igi'i 



179-6 

 181-2 

 i8o-o 



190-9 



+ 27-2 

 + 26-8 



+ 26-4 

 + 17'4 

 + 21-5 



-1-26-7 



A determination of the mean latitude of 42 points in the 

 main stream of the galaxy shows that this stream is not, 

 on the whole, a great circle, for the mean latitude obtained 

 is — i''-74, showing a small but well marked displacement 

 of our system from the central plane towards Coma 

 Berenices, where the north galactic pole is situated. 



Gould's values for the poles of his belt were R..\. = i7i°-2, 

 dec. = -1-30°; the value given in the above table reduces his 

 value for the inclination of the belt to the galactic plane 

 by nearly one half. 



The above position of the plane containing the Wolf- 

 Ravet stars was determined from the positions of seventy-one 

 such stars (excluding those found in the Magellanic Clouds) 

 communicated by Prof. Pickering, and deviates by only 15' 

 from the position obtained for the galaxy. 



Prof. Newcomb has also investigated the law of " star- 

 richness " of the galactic regions, and among other interest- 

 ing results records the following numbers as the richness 

 per square degree as determined from the Bonn and Cordoba 

 Durchmusterungs : — 



Bonn DM. Cordoba DM. 



Near galactic pole S d ... 29-9 



In rifts of the galaxy ... 19 S ... 45-7 



In the galaxy generally ... 246 ... 041 



This result shows that, neglecting the agglomerations, the 

 galactic density is more than double the other in the northern 

 hemisphere, whilst in the southern it is not more than 

 50 per cent, greater. The general result indicates that, 

 even neglecting the condensation of the Milky Way, the 

 richness increases considerably from the galactic poles 

 towards the equator. 



The Persimmon Creek Meteorite. — No. 1380, vo!. 

 .xxvii., of the Proceedings of the U.S. National Museum 

 contains an illustrated description of the physical and 

 chemical characteristics of the meteorite found at Persimmon 

 Creek, North Carolina, in the spring of 1S93. The weight 

 of the main mass of this meteorite was 9 lb. 6 oz., but a 

 fragment weighing i lb. 13 oz. had been previously de- 

 tached. The date of the fall is unknown, but the general 

 appearance when found indicated that it had lain in the 

 soil for a considerable period, whilst the inspection of a 

 polished surface afforded evidence of its meteoritic origin, 

 and showed that it was composed of a more or less con- 

 tinuous matrix of iron containing troilite, schreibersite, and 

 carbon. Separate analyses of the various constituents were 

 made, and the results are given in the paper. 



Enhanced Lines of Titanium, Iron, and Nickel. — la 

 No. 5, vol. .xix., of the Astrophysical Journal, Mr. Herbert 

 .M. Reese, of Yerkes Observatory, gives a list of wave- 

 lengths in the Ti, Fe, and Ni spark and arc spectra re- 

 spectively, indicating a fair number of new enhanced lines. 



The majority of these, however, are only very slightly en- 

 hanced, and will require further confirmator\' evidence 

 before being finally accepted. 



Further Ephemeris for Comet 1904 a. — .-\ supplement 

 to No. 3961 of the Asironomische Nachrichtoi contains a 

 continuation of the ephemeris published by Prof. Nijland 

 in No. 3051 of that journal. This ephemeris gives the 

 positions of the comet for every alternate day from July i.'! 



