March 17, 1892] 



NATURE 



473 



OUR ASTRONOMICAL COLUMN. 



Solar Investigations. — Astronomy ami Astro-Physics for 

 February contains a short note by Prof. Hale, to the effect that 

 photographs have been taken at Kenwood Observatory, showing 

 the H and K lines reversed in regions widely distributed over 

 the sun's disk. These regions closely resemble faculse in 

 appearance. 



At the meeting of the Paris Academy on March 7, Prof. 

 Tacchini communicated a paper on the distribution in latitude 

 of the solar phenomena observed at the Royal Observatory of 

 the Roman College during the second half of last year. Pro- j 

 minences have been more frequent in the northern hemisphere I 

 than in the southern, although in the preceding half-year, and | 

 in 1889 and 1890, they were more frequently observed in the | 

 southern solar hemisphere. The zones of maximum frequency 1 

 occurred between latitudes 40° and 60°. Faculae also have been | 

 most numerous north of the equator, and the zone of maximum ; 

 frequency of these phenomena appears to be between latitudes 1 

 10° and 30°. Spots have been most abundant north of the ! 

 equator, with a maximum frequency in the same zones as ' 

 faculae. 



In the Comptes rendus containing Prof. Tacchini's results, 

 occurs also a note by J. Fenyi, on a remarkable prominence 

 observed at Kalocsa, on February 19, as the recent large spot- ; 

 group was passing over the sun's limb. \ 



New Double Star, 26 Auriga. — In a communication to , 

 the Astronomical Jotirnal, No. 256, Mr. S. W. Burnham re- 

 cords the discovery that 26 Aurigae is a close double star, made 

 up of two nearly equal components. His measures of position- 

 angle and distance for i892"0 are 344°'4 and o"*i5 ; and of 

 magnitudes, 56 and 60. The distance very probably never 

 exceeds a quarter of a second, or the duplicity of the star would 

 have been noticed by many observers of the distant companion 

 discovered by Herschel in 1 783. 



Rotation of Jupiter. — Writing in the March number of , 

 the Observatory, Mr. Denning notes that his observations of one 

 of the chief dark spots in Jupiter's north temperate belt, for the 

 period from August 21 to November 3 (i8o rotations), gave the 

 mean period of rotation 9h. 49m. 36 •9s. Observations of the 

 red spot, from August 7 to February 2 (432 rotations), indicate 

 a mean period of 9h. 55m. 42 '25. The value obtained during 

 the opposition of 1890 was gh. 5Sm. 40"2s., so that the motion 

 of rotation of the red spot would appear to have slackened by 

 two seconds. Since the period of rotation derived from this 

 spot is now 6m. 5s. longer than that given by the dark spots on 

 the north temperate belt, the latter revolves around Jupiter, 

 relatively to the former, in 40^ days. 



The New Star in Auriga.— In No. 3078 of the Astrono- 

 miscAe Nac/tric/ttcn are recordedihree communications relative i 

 to this Nova, two of which refer to its position, while the third 

 deals with its spectrum. The observations of the last-named 

 were made at the Astro-physical Observatory in Hereny, Ungarn, 

 by Herrn Eugen and Gothard, previous to February 15. On 

 the loth and 13th of the same month the following lines were 

 observed : — 



In the first series of observations, the authors give suggestions 

 for some of the lines, and for comparison's sake we have added 

 Mr. Lockyer's also, both of which are included in the following 

 table :— 



IV. .. 



V. . 



VI. .. 



The Lick 



In the second series comparisons were made with Geissler's 

 tubes, and the following measurements were made : — 

 Geiss!er Tubes. Nova. 



5006 501-9 



492-6 492-3 



486-2 486-2 



Spectroscope. — The February number of 

 Astronomy and Astro Physics contains an excellent plate, 

 taken from a photograph by Mr. Barnard, of the spectro- 

 scope on the great 36-inch refractor of the Lick Observatory. 

 In the description of the instrument it is stated that the spectro- 

 scope itself is no less than 130 pounds in weight, while the two 

 brass rods which connect it to the telescope form an extra 

 addition of 75 to 80 pounds. Accompanying the plate, which 

 shows the general arrangement of its parts, is a plan of the 

 instrument which is completely described in the text. Many 

 ingenious ideas have been displayed io the completion of the 

 instrument as regards accessories, such as that of the lighting up 

 of the pointers and production of the comparison-spark. Owing 

 to the great focal length of the telescope, only I '06 inch of the 

 full aperture of the spectroscope can be used, but when it is dis- 

 mounted, it rests on a truck, and its full aperture, 1-50 inch, 

 is then available for laboratory work. 



A Bright Comet. — A circular from the Royal Observatory, 

 Edinburgh, communicated by Dr. Ralph Copeland, and dated 

 March II, contains the following information of the appearance 

 of a bright comet : — 



Dr. L. Swift discovered a bright comet at Rochester, N.Y., 

 at i6h. 5o-im. local mean time, on March 6, its place then 

 being R.A. i8h. 59m., South Declination. 31° 20'. It was 

 moving eastwards. 



The exact place of the comet was observed at the Royal Ob- 

 servatory, Cape of Good Hope, on the 8th inst. to be : — 



Cape of Good Hope Mean Time ... i6h. 58m. 36s. 



Right Ascension I9h. 2m. 27-83. 



South Declination 30° 2' 54" 



Astronomische Naclirichten, No. 3079, also contains some in- 

 formation with regard to this comet. A telegram from Boston 

 contained the following : "Comet Swift was observed by Bar- 

 nard, March 8 0399 G.M.T. ; R.A. app. = 285^51' 20", Polar 

 Distance = 120° 32' 53". Comet is visible to the naked eye." 



Another telegram from Capetown read : " Comet was ob- 

 served March 9-6024 G.M.T. ; Right Ascension — 287° 45' 50", 

 P.D. app. = 119° 16' 12". R.A. March 8 read, 286° 36' 57" 

 Instead of 285° 36' 57"." 



Prof. H. Kreutz in the same number gives the following 

 elements and ephemeris : — 



Elements. 

 T = 1892 March 26-8545 Berlin M.T, 



A' 



CALCULA TION OF TRAJECTORIES OF 

 ELONGATED PROJECTILES. 



S the correct determination of the law of resistance cf the 

 air to the motion of elongated projectiles is a matter of 

 considerable national importance, I hope you will allow me to 

 offer a few concluding remarks explanatory of the present stale 

 of the case. Some results of my first systematic experiments 

 were published in 1868, and General Mayevski, after applying 

 a few tests of his own, adopted my results in his " Traite de 

 Balistique Exterieure," 1872. Siacci made use of these results in 



