ASTRONOMICAL PROG I J Ess IX 1896. 



47 



it at the same rate a< that of the orbital motion of 

 the Moon. This was somewhat ditlicult, because 

 no small, brilliant point could be found on her sur- 

 face for a guide, lie. however, succeeded admira- 

 bly, his beautiful pit-lures showing many details, 

 ami the Moon standing out as a globe instead of a 

 disk: but neither he nor any one else was disap- 

 pointed that no satellite was revealed. His expo- 

 sures were from o m to 6 m in duration. These experi- 

 ments prove that if the Moon has a satellite it is not 

 brighter than a star of the eleventh magnitude. 



( >n the evening of July 21, 1896, Prof. Brooks, of 

 Smith Observatory, Geneva, N. Y., while observing 

 the Moon with the 10-inch telescope, saw a dark, 

 round object pass slowly across the Moon from east 

 to west. He thinks it was a meteor too far beyond 

 our atmosphere to become luminous by friction 

 with it. This assumption, if at the same time it 

 was within the Earth's shadow, would account for 

 its lack of luminosity. It could not have been an 

 ordinary shooting star, which is very small. Its 

 flight across the Moon occupied between 3* and 4 s , 

 which slowness of motion indicates both great dis- 

 tance from the Earth and great magnitude. 



Mars. Dr. Barnard, from an extended series of 

 observations of this planet with the 36-inch tele- 

 scope of the Lick Observatory during the last oppo- 

 sition, found that the so-called "seas," though par- 

 ticularly rich in markings, bore no resemblance to 

 seas, but looked like a mountainous country as 

 seen from a high elevation. The continental shad- 

 ings were observed, but no straight, sharp lines 

 were visible to him. On the other hand, Prof. 

 Percival Lowell, at Flagstaff. Arizona, with a much 

 smaller telescope, claims to have seen several lines 

 of this character. The reputed observations of this 

 planet are so diverse and antagonistic that it is not 

 easy to arrive at conclusions. At the coming oppo- 

 sition some definite knowledge may be attained. 

 The mysterious white spot seen at the last three 

 oppositions on the terminator of Mars, which 

 elicited so much discussion, has reappeared, and 

 wa- seen at the Lick Observatory on Aug. 27, 1896, 

 by Prof. W. J. Hussey. The inference is that it is 

 an illuminated mountain peak, and therefore a 

 prominent and permanent object, and not at all a 

 signaling device to the Earth by the Martian in- 

 habitants, as has been popularly proclaimed. 



Asteroids. Fewer of these tiny worlds were 

 discovered during the year than in any year since 

 1891. Curiously, too, not one has been found visu- 

 ally, but. rather, by the trails on the photographic 

 plates, caused by their orbital motion while the tele- 

 scope is steadfastly and accurately held for hours 

 upon a star. All since the last report are the find- 

 ings of MM. Wolf and Charlois. Palisa, who claims 

 81, seems to have abandoned the quest for these 

 bodies, as his last record is Xo. 226 (Tamara), found 

 in February. 1802. Charlois. with his list of 87, 

 has distanced all competitors. It is highly im- 

 probable that all these planetoids have a magni- 

 tude sufficient to be seen by our telescopes, and it 

 is very likely that they may number many thou- 

 sands. To keep the record of so great a number 

 is laborious indeed, and it is not surprising that 

 astronomers frown upon their further quest. To 

 re-find lost ones is as hard a task as to find comets. 

 A systematic search for the lost -F,thra (132) during 

 the past two years has proved unavailing. Some 

 of these worlds, in their orbital journeys, must pass 

 each other at saluting nearness, if, indeed, they do 

 not occasionally collide. The period of Ottilia (401) 

 is almost exactly half that of Jupiter, rendering the 

 theory of its elements interesting. 



Mr. B. M. Roszel has recently computed the total 

 mass of the first 311 members of the group, assum- 

 ing for them the same albedo as Vesta and the 



mean density of Mars. His conclusion is that it 

 equals 0'003 that of Mars. The throe smallest nn-an 

 distances are : (330) = 2'09 ; Brucia (323) = 2- 16 : 

 and (14!) Mt-dusa = 2' 17. The three greatest are: 

 Thule = 4-26 : (361) = 3-H6 : and (153) Hilda = 

 3 - 96. The greatest density of the group is at dis- 

 tance 2 - 80, precisely that indicated by node's law. 

 The following is the record of discoveries since the 

 last report : 



The following have received names : 



Saturn's Kings. Thelast "Annual Cyclopaedia" 

 gave a brief description of the process used by Prof. 

 Keeler in the determination of his theory that 

 countless millions of discrete particles make up the 

 rings of Saturn. Prof. Campbell, of the Lick Ob- 

 servatory, who has constructed a new spectrograph 

 for the express purpose of testing the validity of 

 the conclusion arrived at by Prof. Keeler, has 

 secured photographs entirely confirmatory, and the 

 scale of the negatives is sufficiently large to show 

 the excess of velocity of the inner edge of the ring 

 over that of its outer edge. As illustrative of the 

 accuracy of Mr. Campbell's photographs, the sub- 

 joined means of three measures may be cited : 

 Velocity due to the planet's rotation = 9 - 77 kilo- 

 metres, differing by 0'52 kilometres from the com- 

 puted value: velocity of the middle of the ring 

 system = 17 - 37 kilometres, differing by 1-41 from 

 the computed value ; and excess of velocity for the 

 inner edge of the ring=3'13 kilometres, differing 

 by 0'74 kilometres from computation. These 

 confirmatory studies would warrant belief in the 

 meteoric composition of the rings : and that the 

 innermost of the three principal rings is translu- 

 cent, allowing the planet to be seen through it, 

 also corroborates its truth. Lately the astronomical 

 journals have discussed the reported observation on 

 April 18, 1896, by M. Antoniadi. a French astron- 

 omer, of three new divisions on Saturn's middle 

 ring. One or two other astronomers claim to have 

 seen, at a later date, something similar. As the 

 outer ring is frequently seen thus divided, and if, 

 as Prof. Keeler has shown, the rings are made up 

 of disjunct components. Antoniadi's observation 

 may be correct, yet the question arises, why have 

 not the users of greater telescopes observed this 

 same phenomen 



Ellipticity of Uranus. By an elaborate series 

 of measures of the equatorial and polar diameters 

 of Uranus, Dr. Barnard has fully proved that the 

 two are unequal, and that, consequently, this planet, 



