ASTRONOMY, PROGRESS OP, IN 1894. 



51 



That its brightness has exhibited strange fluctu- 

 ations is admitted by all, but that it has as- 

 sumed the character of a nebula is disputed. 

 At Lick Observatory it presented to Dr. Barnard 

 the appearance of a small bright nebula con- 

 sisting of a nucleus surrounded by a pretty 

 bright but dense nebulosity 3" in diameter. On 

 the contrary, Mr. Newall, observing with a 25- 

 inch refractor, found the Nova to be truly stel- 

 lar. At Pulkowa it was seen as a nebula. At 

 Upper Tulse Hill, with an 18-inch refractor, it 

 appeared as truly stellar as a star near it. Prof. 

 Vogel has suggested that a possible explanation 

 of the nebulous appearance observed at Lick, 

 Pulkowa, and other observatories, may be found 

 in the chromatic corrections of the " telescopes 

 there employed, the greater part of their light 

 having been near wave length 5,000, if the tele- 

 scopes had been focused on a neighboring star. 

 Prof. Campbell has compared the spectrum, both 

 visual and photographic, with those of 5 nebu- 

 lae, and regards 19 lines thereof, including the 

 lines of hydrogen, which are common alike to 

 nebulae and stars, as probably identical with lines 

 in the spectra of the nebulas. 



Elements of Alpha Centaur!. The orbit 

 of this double star our nearest stellar neighbor 

 which has hitherto been held as uncertain, the 

 estimated periods ranging from seventy-seven to 

 eighty-eight years, is now among the best deter- 

 mined of the known double star. Dr. See finds 

 from the parallax of Gill and Elkin (0'75") that 

 the semimajor axis of the orbit is 23*592 astro- 

 nomical units ; so that the companion moves in 

 an orbit that is about a mean between those 

 of the planets Uranus and Neptune, but the ec- 

 centricity is so great that in periastron the dis- 

 tance (11 '3) but little surpasses that of Saturn, 

 while in apastron it considerably exceeds the 

 distance of Neptune from the sun, becoming 36 

 astronomical units. He makes the time of peri- 

 astron A. D. 1876-62; period, 81'07 years; eccen- 

 tricity, 0-52 ; length of major axis, 32'5" ; length 

 of minor axis, 6'16" ; distance of star from cen- 

 ter, 5-94". . 



Bright-Line Stellar Spectra. Prof. Camp- 

 bell has observed that the 9'3 magnitude star, 

 Durchmusterung + 30 3639, is surrounded by an 

 extensive hydrogen envelope. The star is of the 

 Wolf-Ragot type, and its spectrum is very rich 

 in bright lines, about 30 having been observed 

 between wave lengths 656 and 426. Visually, 

 the most striking features are the continuous 

 spectrum, the bright line at wave length 5,694, 

 the bright-blue band at wave length 4.652, and 

 the very bright hydrogen H. line. This lat- 

 ter line, when observed with a narrow slit, is a 

 long streak extending a very appreciable dis- 

 tance on either side of the continuous spectrum, 

 but seen with an open slit it is a large circular 

 disk about 5" in diameter. This appearance has 

 not been observed in the spectra of any other 

 stars of this type. 



No. 3200 of the " Astronomische Nachrichten " 

 contains a catalogue of 99 stars of remarkable 

 spectra, by Rev. T. E. Espin, of Wolsingham 

 Observatory, Darlington, England. His opin- 

 ion is that the more banded the spectrum the 

 greater is the difference between the visual 

 and the photometric magnitude. Of T Corona 

 he says : " The nebular spectrum has entirely 



disappeared. The region from declination north 

 51 to 56, bounded by 10 h 40 m to ll h 8 m in right 

 ascension, is remarkable for the number of 

 strongly colored stars. Out of 108 stars, as 

 counted on the charts, 17 are orange red, show- 

 ing plainly a grouping of tinted stars in this part 

 of the heavens." 



Comets. The years 1893-'94 were unusually 

 barren of cometary apparitions, but three hav- 

 ing been seen, and two of these Tern pel's and 

 Encke's were expected. The former, Tempel's 

 (periodic) comet II of July 3, 1873, with a period of 

 about five and a quarter years, was observed by 

 Mr. Finlay, of the Cape of Good Hope Observa- 

 tory, on the night of May 8, 1873. Its brightness 

 scarcely equaled that of a star of the eleventh 

 magnitude. It was seen at its next apparition 

 in 1878, but escaped detection in 1883 and in 

 1889. 



Comet a 1894 \yas discovered by Denning, of 

 England, on the evening of March 26. It had a 

 daily motion of about 1 in a southeasterly di- 

 rection. It was at all times very faint. The fol- 

 lowing elliptical elements for this comet are by 

 . Hind: 



J. R. 



Epoch, 1894, March 27'5, Greenwich mean time. 



Longitude of perihelion 



Longitude of node 



Inclination 



Motion 



Period . . . 



21' 22-6" 

 85 2' 38-0" 

 52,749-1 

 525-17108" 

 6 756 years 



The comet announced as having been discov- 

 ered by Edwin Holmes, of London, England, on 

 April 9, proves on investigation to have been a 

 nebula, No. 6503 of Dreyer's New General Cata- 

 logue of Nebulas. 



Comet b 1894 (Gale). This comet, detected on 

 April 1, became visible to the naked eye on the 

 7th of that month, and on the 25th had attained 

 to the fourth magnitude. The tail, though not 

 at any time visible to the naked eye, was on the 

 12th 2 in length and 1 broad, but on the 15th 

 had entirely disappeared. The diameter of the 

 coma was 12', which was constantly maintained. 

 Dr. Kreutz has computed for it the subjoined 

 elements : 



Epoch, 1894. April 13-5576, Berlin mean time. 



Node to perihelion 324 17' 57'8" 



Longitude of node 206 21' 13-5" 



Inclination 87 3' 30-6" 



Log. of perihelion distance 9-992746 



On the photographic negative plates of the 

 total solar eclipse of April 16, 1893, appears a 

 nebulous object which can not be other than a 

 comet. It is present on 12 of Prof. Schaeberle's 

 plates from Guiana, on 3 Harvard College Ob- 

 servatory plates, on 2 British plates taken in Bra- 

 zil, and on 3 British plates in Africa. Study of 

 these negatives shows that the object had a pro- 

 gressive motion, and that unquestionably it was 

 a comet and ought to receive the designation of 

 comet I, 1893. which cognomen Dr. Krueger has 

 given it. 



Encke's comet was discovered on Nov. 1, 1894, 

 by Cerulli, of Italy. 



Comet V 1889 (Brooks). A thorough dis- 

 cussion of this comet has recently been made by 

 Mr. C. Lane Poor, with a view of determining 

 or disproving its identity with the celebrated 

 Lexel's comet of 1770. He finds that comet 

 Brooks, though originally moving in an orbit of 



