ASTRONOMICAL PROGRESS IN 1898. 



51 



among themselves. Since attention is called to their 

 existence, and drawings of their appearance have 

 been widely distributed among astronomers, it is 

 amazing that our best observers, with powerful tel- 

 escopes of marvelous perfection, see nothing that 

 others claim to see with small apertures and low 

 powers. Prof. A. E. Douglas, of the Lowell Ob- 

 servatory, at Flagstaff, Arizona, who, with Percival 

 Lowell, is the champion of the theory that the 

 markings have a real existence, and may possibly 

 be canals, says : " I decided long since that in plan- 

 etary work the greatest efficiency is obtained with 

 the smallest aperture that supplies the required 

 illumination. An inch-and-a-half lens shows the 

 markings on Venus nicely, but they are not so well 

 defined as in a lens of three inches." He further 

 says, in " Monthly Notices of the Royal Astronom- 

 ical Society" for May, 1898. that he ''has had at 

 his command various optical powers on telescopes 

 of 3, 6, 13, 18, and 24 inches aperture, using gen- 

 erally a magnifying power of 150 diameters, and 

 has spent many thousand hours on Venus alone, 

 using the telescope in both normal and reversed 

 positions, which shows that their object glasses and 

 eyepieces are free from fault." 



Mars. Capt. P. B. Molesworth, of Ceylon, has 

 forwarded to the Mars section of the British 

 Astronomical Association a memoir, accompanied 

 by seven very detailed drawings and a map of Mars, 

 as seen by his 9-inch reflector. The results 

 arrived at are the most remarkable yet published. 

 He independently confirms the existence of the fog 

 that covered the north polar region to the extent 

 of 60, equal to 2,240 miles. He reports on observ- 

 ing 15 to 20 of the lakes seen by others. In addi- 

 tion to the lakes he gives a list of 31 canals he 

 had observed. 8 of which were seen double on 

 various occasions. Something like 50 canals have 

 been recorded as seen by others. As to the origin 

 of the network of the so-called canals, astronomers 

 are not agreed ; in fact, many deny their existence. 

 Astronomers are pretty generally agreed that the 

 supposed canals are not canals at all, but dikes 

 thrown up to control the spread of surface water. 



The extraordinary discrepancy in the results of 

 many astronomical determinations of the polar 

 compression of Mars is one of the most amazing in 

 the history of astronomical measurements. Sir 

 William Herschel made the compression -^ ; Kaizer, 

 r }-r; Main, ^-; Young, YI-T; Barnard, with the 36- 

 inch telescope at the Lick Observatory, T J^; Schur, 

 -4 1 7 ; Adams. ? |g-. Daws found none, and on one 

 occasion found an elongation. Arago, from obser- 

 vations of thirty-six years, got. the, enormous value 

 of B l (,-. The polar compression of the earth is ^y-, 

 equal to 26 miles. 



Asteroids. The most remarkable discovery in 

 astronomy since Barnard found the fifth satellite 

 of Jupiter has recently been cabled from Europe. 

 Mr. G. Hitt discovered, on Aug. 13, an asteroid 

 whose provisional number is DQ, having an extraor- 

 dinarily rapid motion. As computed from obser- 

 vations made on Aug. 14, 23. and 31, it was found 

 that at perihelion the little planet will be nearer 

 the sun than Mars; or, in other words, the perihelion 

 of its orbit lies between the Earth and Mars. This 

 is the only known instance of an asteroid orbit 

 whose eccentricity is>such that its perihelion point 

 lies inside that of Mars. This discovery raises anew 

 the question whether the almost microscopic satel- 

 lites of Mars were not originally asteroids, and also 

 whether, in the coming ages, he may not obtain 

 another. The field of imagination here is wide, and 

 asks if the little fifth satellite of Jupiter may not also 

 have been originally an asteroid, the eccentricity of 

 whose orbit was so great as to cause its aphelion to 

 extend to or beyond Jupiter's orbit. 



The follow ing elements of this remarkable member 

 of the asteroidal group have been computed for it: 



Epoch 1898, Aug. 31.5 Berlin mean time. Mean 

 anomaly. 220 14' 3.7" ; node to perihelion, 178 28' 

 20.2"; longitude of node, 303 48' 53"; inclination, 

 11 6' 57.1"; angle of eccentricity, 13 13' 3.8"; 

 eceenirie.ity, 0.22865; 2,010.131"; mean daily mo- 

 tion, semi-axis major, 1.4G057 ; period, 644.7 days. 



At perihelion it approaches within 14,000,OCO 

 miles of the Earth. At a favorable opposition, 

 therefore, this asteroid will afford the best opportu- 

 nity known for determining the Sun's parallax, and 

 therefore the dimensions of the solar system and the 

 diameter of every planet. At this opposition the 

 planet was of about the eleventh magnitude, but 

 when its perihelion and opposition occur simulta- 

 neously it will be of the sixth magnitude and visible 

 to the naked eye. 



Since the last report, nine asteroids have been 

 discovered, as follow : 



Jupiter's Satellites. Prof. A. E. Douglas, in 

 " Astronomische Nachrichten," has given a descrip- 

 tion, accompanied bv an illustrated sheet of the 

 markings on Jupiter's third satellite, made at the 

 Lowell Observatory, at Mexico, and Flagstaff with 

 the 24-inch Clark refractor. They much resemble 

 those alleged to be visible on Mercury, Venus, and 

 Mars. From these markings he calculates the rota- 

 tion period to be nearly one week, being about the 

 same as the period of its revolution around Jupiter. 



After a reduction of the observations on the fourth 

 satellite was begun he met with this curious fact: that 

 either the satellite rotates in one half of its period of 

 revolution, or the detail is symmetrical with respect 

 to its axis. From the motion exhibited from day 

 to day by the more conspicuous points of its detail, 

 he judged the latter to be the case. He also made 

 prolonged observations of all the satellites except 

 the fifth. From observations of the first satellite, 

 he concludes that the rotation period is 12 h 28 m 48. 

 Its axis is assumed to be perpendicular to the plane 

 of its orbit. His micrometer measurements give a 

 very elliptical form to the first satellite, which would 

 indicate a period of rotation much shorter than that 

 given above. 



Saturn. The following is a brief resume of dis- 

 coveries made on this interesting planet, notably at 

 the Juvisy Observatory, France, in 1897 and 1898, 

 by MM. Flammarion and Antoniadi : The belt 

 north of the equator is always seen double by them. 

 The dark spots discovered on the belt in 1891 by 

 Stanley Williams were frequently seen at Juvisy in 

 1896, 1897, and 1898 by both observers and by per- 

 sons who knew nothing of their existence. Few 

 a'stronomers, however, have been able to see them. 

 No trace of Encke's division of the outer ring (A) 

 was seen by them, though assiduously searched for ; 

 but Cassini's division was easily seen all round the 

 ring. Extensive observations were made on the 

 middle ring (B), but little detail was observed save 

 the convincing evidence that its inner edge is not a 

 real edge toward the inner ring (C) or the gauze 

 ring. The planet has lately been better situated for 

 observation than for the past fifteen years, and the 

 ring system is open the widest possible to our line 

 of sight. The observers at Juvisy declare that the 



