36 



ASTRONOMICAL PHENOMENA AND PROGRESS. 



discovered in 1878, bringing the number up to 

 191. The dates and places of discovery, to- 

 gether with the names of the discoverers, are 

 given in the following table : 



The following minor planets, discovered in 

 1877, have been named since the issue of our 

 last volume: No. 171, Ophelia; 172, Baucis; 

 and 178, Belisana. 



The Mass of Saturn's Rings. In the 

 "Comptes Rendus," vol. Ixxxv., No. 16, M. 

 Tisserand has given a new determination of 

 the mass of Saturn's rings. Bessel's value of 

 the mass was found from its disturbing effect 

 on Titan, the largest satellite. M. Tisserand 

 includes in his discussion the motions of the 

 other satellites, and finds that the change in 

 the position of their orbits is not so much due 

 to the attraction of the ring as to that of the 

 protuberant matter about Saturn's equator, 

 M. Tisserand's value of the mass is -^ the 

 mass of Saturn being 1. This is less than one 

 fifth of the value obtained by Bessel. 



Comets. The first comet of 1878 was dis- 

 covered by Mr. Lewis Swift of Rochester, N. Y., 

 on the 7th of July. It had a perceptible cen- 

 tral condensation, but neither tail nor nucleus. 

 Its motion is direct ; its inclination. 78 degrees ; 

 and its perihelion distance was' 128,000,000 

 miles. 



The second comet of 1873 was detected on 

 its first, predicted return by M. Tempel of Ar- 

 cetri, near Florence, on the 19th of July, 1878. 

 It had the appearance of a nebula three or 

 four minutes in diameter, with several nuclei. 



With the aid of Dr. Von Asten's ephemeris 

 Mr. John Tebbut of Windsor, New South Wales, 

 detected Encke's cornet on the evening of Au- 

 gust 3d. This is the eighteenth perihelion pas- 

 sage since its periodicity was discovered by 

 Encke, and the comet has been observed at 

 each successive return. Its appearance in 1878 

 was that of an extremely faint nebulosity. Mr. 

 J. D. Hirst, writing from Sydney, New South 

 Wales, under date of August 21st, says: 



The comet is a very inconspicuous obiect, even 

 with alow power and the full aperture of the 11*- 

 1 1 1 ey r ? fractor - It appears as a circular neb- 

 ulous body, showing signs of condensation in the 



inter, but no distinct nucleus. On the evening ot 

 the 20th of August two tenth-magnitude stars were 

 observed m the field with the comet, the motion of 

 the latter rendering it apparent that it must pass 

 yervclose to, if not immediately over, one of them. 

 Phis actually took place just before the comet set, 

 the center of the comet passing directly over the 



star. It is interesting to record that this faint tenth- 

 magnitude star was not even dimmed, much less 

 obliterated, by the interposition of the densest part 

 of the comet ; it shone right through the center and 

 most condensed part as bright as it had before ap- 

 peared against the dark background of the sky. The 

 other star of the same magnitude in the field formed 

 an accurate standard of comparison by which to de- 

 termine any diminution of light in the former. 



The Origin of Comets. The "American 

 Journal of Science" for September, 1878, con- 

 tains an elaborate article on the origin of 

 comets, by Prof. H. A. Newton of Yale Col- 

 lege. In the theory of Kant comets as well as 

 planets were originally parts of the nebulous 

 mass from which the solar system was formed. 

 Laplace, on the other hand, regarded them as 

 of extraneous origin. Prof. Newton discusses 

 such cometary phenomena as have an obvious 

 bearing on this interesting question, and finds 

 a decided preponderance of evidence in favor 

 of a foreign origin. He grants, however, that 

 the group of comets with periods correspond- 

 ing with those of the minor planets may have 

 originated in the solar nebula. 



Meteoric Showers. The meteors of January 

 lst-3d called Quadrantids from the fact that 

 their radiant is in Quadrans were observed 

 in unusual numbers by Prof. Herschel at Hawk- 

 hurst, England, on the morning of January 2, 

 1878. In thirty minutes Prof. Herschel counted 

 twenty meteors, of which seventeen were Quad- 

 rantids. Two were as bright as Jupiter, five 

 equal to first-magnitude, six equal to second-, 

 and the rest about equal to third-magnitude 

 stars. 



The Meteors of April 19th -23d. The 

 "Monthly Notices" for May, 1878, give the 

 results of Mr. W. F. Denning's watch fcr 

 meteors of the April shower on the 20th, 21st, 

 and 22d of the month. Twelve meteors were 

 seen which belonged, undoubtedly, to the group 

 of Lyraids. The radiant, very exactly deter- 

 mined, was in R. A. 272, N. decl. 32. 



The Aiigust Meteors. The meteors of Au- 

 gust 8th-12th were observed in 1878 under 

 unfavorable circumstances; cloudy weather in 

 many places, as well as bright moonlight, in- 

 terfering with the observations. In " The Ob- 

 servatory" for September, Mr. H. Corder of 

 Chelmsford, England, gives the following re- 

 sults of his observations: During four hours 

 on the night of the 10th he counted 113 me- 

 teors, of which 97 were Perseids. Of these, 

 60 had visible streaks and 20 were colored. 

 The maximum was from 2 h - 15 m - to 3 h - 15 m -,- 

 during which hour he saw 44 meteors. The 

 radiant was in R. A. 43, N. decl. 56. One 

 meteor was seen absolutely stationary at R. A. 

 47, N. decl. 58. On the same night Mr. W. 

 F. Denning, watching at Bristol, England, saw 

 130 meteors in four hours and a half. During 

 the half hour ending at 3 o'clock, when the 

 moon had set, he counted 33. 



Meteoric Fire-balls. In " The Observatory " 

 for February and March, 1878, Capt. G. L. 

 Tupman discusses the observations of a great 



