66 



ASTRONOMICAL PHENOMENA AND PROGRESS. 



at the same time, and passed through it in par- 

 allel lines. They continued visible about forty 

 seconds. A meteorite composed in part of 

 iron, nickel, and sulphur, fell in Turkey on the 

 20th of May. 



The Zodiacal Light. Prof. Arthur W. 

 Wright, of Yale College, communicates to the 

 American Journal of Science and Arts (May 

 .and July, 1874) some interesting researches in 

 regard to the nature of the zodiacal light. 

 The results of the investigation are briefly 

 stated as follows : 



1. The zodiacal light is polarized in a plane pass- 

 ing through the sun. 



2. The amount of polarization is, with a high de- 

 gree of probability, as mueh as 15 per cent., but can 

 hardly be as much as 20 per cent. 



3. The spectrum of the light is not perceptibly 

 different from that of sunlight, except in intensity. 



4. The light is derived from the sun, and is re- 

 flected from solid matter. 



5. This solid matter consists of small bodies (me- 

 teoroids) revolving about the sun in orbits crowded 

 together toward the ecliptic. 



The theory that the zodiacal light is pro- 

 duced by the reflection of the sun's rays from 

 innumerable asteroids interior to the earth's 

 orbit, and too small to be separately observed, 

 was proposed by Oassini two hundred years 

 since. Its demonstration, however, was first 

 announced in the memoirs above quoted. Prof. 

 Wright, in a third paper, which was read be- 

 fore the American Association for the Ad- 

 vancement of Science, in August, 1874, gives 

 reasons for regarding the orbits of the reflect- 

 ing bodies as very eccentric. 



The Inner Satellites of Uranus. The ques- 

 tion of priority in the discovery of the inner 

 satellites of Uranus has been recently exam- 

 ined by Prof. Edward S. Holden, of the Wash- 

 ington Observatory. After discussing the 

 original observations, together with those of 

 Lamont, Struve, and Lassell, Mr. Holden con- 

 cludes that not only Titania and Oberon, but 

 also the . inner satellites, Ariel and Umbriel, 

 were really discovered by Sir William Her- 

 schel, and that the observations of Lassell in 

 1847 were but rediscoveries of the same bod- 

 ies. The justice of this conclusion is called in 

 question by Mr. Lassell, who ably vindicates 

 his own exclusive claim to the original dis- 

 covery. " From a less distinguished author- 

 ity," he remarks, "than that of an astronomer 

 writing from the Washington Observatory, 

 the assertion might have passed unnoticed, 

 from a conviction that it would not obtain 

 credence; but Prof. Holden's conclusions will 

 probably be held to have an importance or 

 prestige,, which compels me at some length to 

 prove how perfectly erroneous they are. I 

 myself claim to T)e t'he original and only dis- 

 coverer of these inner satellites, Ariel and 

 Umbriel, single-handed and unassisted, with- 

 out coadjutor, rival, or competitor." 



Among the reasons assigned by Mr. Lassell 

 for concluding that none of the stars noticed 

 by Sir William Herschel in the vicinity of Ura- 

 nus could have been Ariel and Umbriel, is the 



fact that the means at his disposal "did not 

 suffice to reveal to him the existence of these 

 most minute bodies." 



Stellar Parallaxes. Dr. Brunnow, the As- 

 tronomer Royal for Ireland, has devoted special 

 attention for several years to the determina- 

 tion of the parallaxes of certain fixed stars. 

 The star known as No. 1,830 of Groombridge's 

 catalogue was supposed, from the fact of its 

 having a large proper motion, to be compara- 

 tively near us. The observations of Prof. 

 Brunnow, however, have shown its annual 

 parallax to be only nine-hundredths of a sec- 

 ond a parallax which corresponds to a dis- 

 tance ten times greater than that of Alpha 

 Oentauri. From a series of observations on 

 Sigma Draconis, the same distinguished as- 

 tronomer obtains a parallax of one-fourth of a 

 second ; for No. 3,077 of Bradley's catalogue, 

 seven-hundredths of a second; and for the 

 double star No. 68, Pegasi, five-hundredths of 

 a second. The distance corresponding to the 

 last would not be traveled by light in less than 

 sixty years. 



Periods of Binary Stars. M. Flammarion, 

 of Paris, has redetermined the periods of the 

 folio wing' double stars: 



Zeta Hercnlis 34.57 years. 



Eta Coronae Borealis 40.17 " 



Xi Ursse Majoris 60.00 " 



Gamma Virginia 175.00 " 



The first of these periods, it will be observed, 

 is somewhat greater than that of Saturn, 

 while the last is a little greater than the period 

 of Neptune. M. Flammarion remarks that 

 the large number of observations used in the 

 calculation renders his conclusions entirely 

 trustworthy. 



Distribution of the Bright Fixed Stars. A 

 paper on "The Number and Distribution of 

 the Bright Fixed Stars " was read before the 

 American Association for the Advancement 

 of Science, in August, 1874, by Dr. B. A. 

 Gould, Director of the Cordoba Observatory. 

 In this memoir the existence of a zone or great 

 circle of very bright stars, intersecting the 

 Milky-Way at an angle about equal to that be- 

 tween the equator and the ecliptic, is, for the 

 first time, distinctly recognized. Dr. Gould re- 

 marks : 



It has been generally assumed that the number 

 of visible stars of any given magnitude, whether 

 brighter or fainter, diminishes as their distance from 

 the Milky- Way increases. In the elevated position 

 and pure atmosphere of Cordoba, this nebulous cir- 

 cle is seen with a vividness far surpassing that to 

 which we are accustomed here ; and, moreover, most 

 of that portion which lies in the Southern Hemi- 

 sphere is intrinsically brighter than the northern 

 half; so that its position is far more clearly defined 

 than I have ever seen it elsewhere. And few celes- 

 tial phenomena are more palpable there than the ex- 

 istence of a stream or belt of bright stars, including 

 Canopus. Sirius, and Aldebaran, together with the 

 most brilliant ones in Oarina, Puppis, Columba, Canis 

 Major, Orion, etc., and skirting the Milky- Way on 

 its preceding side. When the opposite half of .the 

 Galaxy came into view, it was equally manifest that 

 the same is true there also, the bright stars likewise 

 fringing it on the preceding side, and forming a 



