ASTRONOMICAL PROGRESS IN 1899. 



57 



.curate elements of its orbit: Time of perihelion 

 passage, 1898, Nov. 23.14, Greenwich mean time; 

 from node to perihelion, 123 22'; longitude of 

 node, 96 10'; inclination, 140 19'; perihelion 

 distance, 0.7564. 



Comet 1898 J (Chase) .This extremely faint 

 comet was discovered by photography by Mr. 

 F. L. Chase, an assistant at Yale College Observa- 

 tory, who on Nov. 14 photographed the radiant 

 of the November meteoric shower in the sickle 

 of Leo. When the plate was developed nothing 

 indicating a new point of light or a trail by a 

 moving object was seen. But two weeks after- 

 ward the director, inspecting the negative, saw 

 a minute speck slightly elongated. He requested 

 astronomers at other observatories to inspect 

 their plates, and the speck was found at the 

 same place. When the region was examined 

 with one of our great telescopes the mysterious 

 object was identified as a comet. The shortness 

 of the trail was accounted for by the slow mo- 

 tion of the comet and the short exposure, com- 

 bined with its extreme faintness. From obser- 

 vations made on Nov. 14, 23, and 25, and Dec. 

 5, Prof. Moller has computed the following or- 

 bital elements: Time of perihelion passage, 1898, 

 Sept. 19.65, Berlin mean time; node to perihelion, 

 4 23' 9.2"; longitude of node, 95 47' 0.2"; in- 

 clination of orbit, 22 28' 25.2"; longitude of peri- 

 helion distance = q. 0.357918. These elements in- 

 dicate that the orbit is a parabola. 



Comet A 1899 (Swift) was discovered by Dr. 

 Lewis Swift, director of the Lowe Observatory, 

 Echo Mountain, California, on the evening of 

 March 3. It was the brightest and most inter- 

 esting comet that has appeared since the great 

 comet of 1882. It had an interesting history 

 while under observation, which was nearly four 

 months. For full particulars the reader is re- 

 ferred to the Astronomical Journal, No. 404, 

 where a double 'head and double nucleus are rep- 

 resented and fitful variations of brilliance are 

 described. This variation in brilliance was a new 

 feature in cometary astronomy. The discoverer 

 from its subsequent behavior has reason to be- 

 lieve that a sudden outburst occurred just prior 

 to its discovery, rendering it visible to the naked 

 eye. At this time a phenomenon was seen which 

 could not be seen the next evening nor at any 

 subsequent evening, and which never has been 

 seen appended to any comet. The bright coma 

 visible to the naked eye was centrally super- 

 imposed on another very much the larger and of 

 unimagined faintness, the marginal demarcation 

 of the two being sharply defined. The following 

 parabolic elements have been computed: Time 

 of perihelion passage, April 13.0148; node to peri- 

 helion, 8 48' 52": longitude of node, 25 0' 55"; 

 inclination, 146 15' 48"; logarithm of perihelion 

 distance, 9.51311. 



Comet B 1899 = Turtle's of 1858 = MecJiain's 

 Comet of 1790. This interesting periodic comet 

 was rediscovered by Dr. Wolf on March 5, 1899. 

 It has a period of 13.7 years. It remained unob- 

 served from 1790 to 1858. Its period is the 

 longest of all the short-period comets. 



Comet C 1899 (Holmes) = Comet III 1893 

 This was rediscovered, June 10, by Perrine at the 

 Lick Observatory with the 36-inch telescope, in 

 which it appeared not brighter than a star of the 

 sixteenth magnitude. This is its first return 

 since its first discovery by Holmes in 1893. 



Comet D 1899 ( Tcmpcl's ) = Comet II 1873. 

 This short-period comet of six years was also re- 

 discovered by Perrine on May 7, almost exactly 

 at the place computed for it by Prof. Schulhof, 

 the error being only 2' of arc. 



The elements of Comet E 1898 (Perrine) resem- 

 ble those of the Comets of 1684, 1785 I, Cornet B 

 1898, and Pons's comet of 1812 = Comet Pons- 

 Brooks of 1884. These facts strongly indicate 

 that they all belong to the same family, although 

 only the latter is periodic. The elements of the 

 bright comet discovered by Prof. Brooks, as 

 stated above, bear a strong resemblance to that 

 of 1881 IV, although Dr. Stechert has computed 

 for it a period of not less than one hundred thou- 

 sand years. For comparison the elements of 

 both are subjoined: 



Comet Brooks. Comet 1881 IV. 



Node to perihelion 123 33' 48" 122 7' 19" 



Longitude of node 96 20' 1" 97 2' 37" 



Inclination 140 21' 4" 140 13' 54" 



Log. of perihelion distance. 9.887852 9.80178 



Comet E 1899 (Giacobini) was discovered at 

 Nice, France, on Sept. 29, in right ascension 16^ 

 26m 3.2s, declination south 5 10'. The following 

 elements have been computed from observations 

 of Oct. 3, 6, and 9: 



TIME = 1899, SEPT. 18.3115 BERLIN MEAN TIME. 



Node to perihelion 12 47' 26" ) 



Longitude of node 272 4' 48" > 1899.0. 



Inclination 76 33' 17" ) 



Logarithm of q = 0.25273. 



Variable Stars. For three hundred years it 

 has been known that Beta Persei (Algol or 

 Demon star) varied periodically through nearly 

 two magnitudes; also that Omicron Ceti (Mira 

 the Wonderful) varied from the third magnitude 

 to invisibility, going through all its changes in 

 about eleven months. Many others, as now 

 known, are at their maxima visible to the un- 

 assisted eye, but at their minima are beyond the 

 reach of ordinary telescopes. Many theories have 

 been advanced to account for their variability. 

 The number of these now known amounts to 

 more than a thousand. As amateurs can engage 

 profitably in the work, no telescope being re- 

 quired, the list is increasing rapidly. In several 

 particulars Algol is the most interesting, as the 

 theory to account for its behavior is recognized 

 by all astronomers as correct viz., that it has 

 a dark companion revolving round it, the plane 

 of whose orbit is coincident with our line of 

 sight, which periodically eclipses it. If this the- 

 ory be true, then the bright component must al- 

 ternately approach and recede from our solar sys- 

 tem. The spectroscope has settled that question 

 in the affirmative, giving the following data: 

 Diameter of Algol, 1,000,000 miles; diameter of 

 companion, 800,000 miles; distance between them, 

 3,000,000 miles; velocity of companion, 55 miles 

 a second. 



The shortest known* variable is U Pegasi, 

 changing in 5 h 35 m . Nova Auriga, when discov- 

 ered, appeared as an ordinary star of the fifth 

 magnitude, but soon began to decline rapidly in 

 brightness, until it reached about the seventeenth 

 magnitude, being a difficult object in the great 

 Lick telescope. It has a remarkable spectrum, 

 showing many bright narrow lines and broad 

 dark bands. Later it increased to the tenth mag- 

 nitude, and is now a nebulous star. Examining 

 the Draper memorial photographs, Mrs. Fleming, 

 of Harvard College Observatory, discovered a 

 new star in Sagittarius, which was first of the 

 fifth magnitude, and therefore easily visible to 

 the naked eye, but by March, 1899, it had de- 

 clined to the tenth. The spectrum resembles 

 those of many other variables, many of the bright 

 lines being due to hydrogen. 



No so great advance in astronomy has been 

 made as in the discovery and classification of 



