ASTRONOMICAL PHENOMENA AND PROGRESS. 



51 



from time to time. Observers have sometimes 

 described the outer ring as broken up into a 

 number of concentric rings, thus giving rise to 

 the theory that this ring was sometimes con- 

 tinuous, and sometimes divided up. A some- 

 what ill-defined shaded line, known as the 

 Encke division, is always seen under favorable 

 circumstances near the outer edge of the outer 

 ring, and this appearance may have given rise 

 to the impression of one or more divisions. 

 Nor has any separation ever been seen between 

 the dusky ring and the inner edge of the bright 

 ring. In fact, the latter seems to fade into the 

 former by insensible gradations of shade. On 

 the other hand, Mr. Trouvelot, who was for- 

 merly attached to the Harvard College Ob- 

 servatory, but who has returned to Mendon, 

 France, expresses himself very decidedly in 

 favor of the supposed changes. These changes 

 he claims to consist 



1. In variations of the brilliancy and color 

 of the surface of the rings. 



2. In changes, sometimes slow and some- 

 times quite rapid, in the form of the shadow 

 cast by the globe of the planet upon the 

 rings. 



3. In variations which affect the ring 

 throughout its entire thickness. At the last 

 opposition he found that the Encke division 

 had entirely disappeared, and that its place 

 was taken by a new division, more marked and 

 nearer to the old and well-known one of Cas- 

 sini. He also noticed that the narrow belt be- 

 tween this new division and the old one was 

 more brilliant than he had ever before seen it, 

 and was subject to fluctuations. The question 

 of variability must still be an open one which 

 can be decided only by comparing simultaneous 

 observations made by observers at distant sta- 

 tions. Until this is clone it will be safest to 

 attribute the supposed changes to variations in 

 the state of the atmosphere and the eye of the 

 observer. 



The physical features of the ball of the 

 planet have been investigated by a number of 

 English investigators. At the January meet- 

 ing of the Royal Astronomical Society, Mr. 

 Green said that the outline of the ball could 

 be traced on either side for some little dis- 

 tance through the dusky ring. This coincides 

 with the observations made some years ago 

 by Mr. Trouvelot with the great Washington 

 telescope, and, if correct, show conclusively 

 that the dusky ring is transparent, at least 

 near its inner edge. The studies made by 

 Mr. Green and Mr. Pratt indicate a remark- 

 able resemblance between the balls and other 

 markings on Saturn and those on Jupiter, the 

 principal difference being that the former are 

 very much fainter, and can therefore be made 

 out only under favorable conditions. Around 

 the equatorial region extends a zone of a creamy 

 yellow tint, which is usually free from mark- 

 ings. At about latitude 10 there is a strongly 

 marked narrow belt, sometimes gathered into 

 wispy notches and curved markings, as on Jupi- 



ter. The color of this belt is a Vandyke brown. 

 Several alternate 'belts, ranging from a creamy 

 tint to a very pale rose madder, are seen in mid- 

 dle latitudes, and terminate with the bluish- 

 white polar cap. 



The Zone of Asteroids. The discoveries of small 

 planets, which fell off so remarkably during 

 the years 1882 and 1883, were recommenced 

 with their old vigor in 1884, nine being dis- 

 covered during the latter year. This carries 

 the whole number now known up to 244. 

 The following table -shows the discoveries of 

 the year : 



LIST OF SMALL PLANETS DISCOVERED IN 1884. 



Cometary Discoveries in 1884. The first comet 

 discovered in 1884 is catalogued properly with 

 the comets of the preceding year, as it passed 

 perihelion on Dec. 25, 1883. It was discovered 

 by Ross, an amateur observer at Esternwick, 

 near Melbourne, Australia, on Jan. 7, 1884, a 

 "faint nebulous object with an ill-defined, tail- 

 like projection." By January 18th, the tail had 

 reached a length of a degree and a half. The 

 comet was invisible in the northern hemisphere,- 

 and was under observation at the southern ob- 

 servatories for only about a month. 



The first comet of 1884, in order of perihe- 

 lion passage, was that discovered by Brooks 

 at Phelps, N. Y., on Sept. 1, 1883 (comet C, 

 1883). As soon as sufficient observations were 

 obtained to determine approximately the orbit, 

 it became evident that this was a return of the 

 comet originally discovered by Pons at Mar- 

 seilles on July 20, 1812, one of a group of 

 which Halley's comet is another member, hav- 

 ing a period of about seventy-five years, and an 

 aphelion a little beyond the orbit of Neptune. 

 As the second comet of this group to return to 

 perihelion, the comet was looked for with con- 

 siderable interest, and this interest was subse- 

 quently increased when observations showed 

 the rapid change* suffered by the head in ap- 

 proaching the sun, and the curious fluctuations 

 in the brightness of the nucleus. From a star 

 of the eleventh or twelfth magnitude at the 

 time of discovery, it increased gradually in 

 brightness to the 7-J- magnitude on September 

 23, and then suddenly decreased to the ninth 

 magnitude on September 29. A gradual in- 

 crease again took place till October 6, when it 

 was a second time noted as 7 magnitude, and 

 then, after another short period of decrease, a 

 final steady increase in brightness began about 

 the first of November, and continued until a 

 maximum of the second magnitude was reached, 



