50 



ASTRONOMICAL PROGRESS AND DISCOVERY. 



taken respectively at Washington, D. C. ; Ce- 

 dar Keys, Fla. ; San Antonio, Tex. ; Cerro 

 Roblero, N. M. ; Wellington, South Africa; 

 Santa Cruz, Patagonia ; Santiago, Chili ; Auck- 

 land, Ne\v Zealand ; Princeton, N. J. ; and the 

 Lick Observatory, Cal. : 



JT= 8-847" 0-012" 

 6 A = + 2' -'.'3 

 6D= + 1 254 



and the corresponding mean distance from the 

 earth to the sun is 92,385,000 miles, with a 

 probable error of only 125,000 miles. These 

 numbers are doubtless close approximations to 

 the results that will be obtained from the com- 

 plete discussion of all the photographs; but 

 they can not be regarded as final, for several 

 reasons, chief among which is the fact that the 

 reduction of the position-angles of Venus rel- 

 atively to the Sun's center is still unfinished. 

 When these angles are combined with the 

 distances, it is likely that the probable error 

 of the parallax will be somewhat reduced. 

 The photographs taken at Lick Observatory 

 seem to indicate that for altitudes 4,000 feet 

 above sea-level, the values of the refraction 

 given by the tables in general use are some- 

 what too large. Prof. L. Cruls has published 

 the results of the Brazilian observations of the 

 transit of Venus made at three stations, St. 

 Thomas (Antilles), Pernambuco, and Punta- 

 Arenas. The final result for parallax is IT = 

 8'808". This curiously coincides exactly with 

 the result of the English observations, taking 

 the lowest probable result. 



Eclipses of the Moon. Two interesting total 

 eclipses of the moon occurred in 1888. The first 

 on January 28, and the second at midnight, July 

 22. The moon rose eclipsed on January 28, 

 bat was beautifully visible on July 22. Ob- 

 servers of the eclipse of January 28 report a 

 remarkable contrast between the visibility of 

 the eclipsed moon on that occasion and in Oc- 

 tober, 1884. The moon at the latter date was 

 scarcely visible, while at the former it shone 

 with a light that was plainly visible. Prof. 

 Filopanti, of Bologna, thinks that the red color 

 during the total eclipse arose in part from a 

 phosphorescent quality of the exposed lunar 

 surface. To astronomers these two eclipses of 

 the moon were especially interesting as afford- 

 ing opportunity for the observation of the oc- 

 cultations of faint stars by the moon. Dr. 

 Dollen, of the Pulkowa Observatory, Russia, 

 prepared lists of stars to be occulted by the 

 moon, and sent these to many observatories in 

 Europe and the Dnited States, with the request 

 that the times of disappearance and reappear- 

 ance be noted and forwarded to him. He re- 

 ports that he has obtained in this way observa- 

 tions of 783 phenomena (396 disappearances 

 and 387 reappearances), made at fifty-five dif- 

 ferent places. The places of observation are 

 so favorably situated that he considers there is 

 ample material for calculating the place, the 

 diameter, and possibly the ellipticity and the 

 parallax of the moon. For the parallax and 



distance of the moon he has bases of 90 in 

 latitude and 150 in longitude. 



Asteroids. The small planet Istria (183) was 

 rediscovered by Palisa, April 7, 1888. Of the 

 first 250 of the planets, 238 have been observed 

 at second opposition. Only two of the excep- 

 tions are between numbers 200 and 250. Since 

 the article in the " Annual Cyclopaedia " for 

 1887 was written, No. 268 has been named 

 Adorea; 269 has not been named, and 270 

 has been styled Anahita. The opposition in 

 longitude of Sappho (80) occurred April 12, 

 1888. Observations were made by many as- 

 tronomers to determine the correction to the 

 elements of the planet's orbit. In August and 

 September, 1889, this planet will make a near 

 approach to the earth, on account of the ec- 

 centricity of its orbit and the commensura- 

 bility of its period with that of the earth. Ob- 

 servations of this planet will be taken in 1889 

 to determine the value of solar parallax. Prof. 

 C. H. F. Peters gives the following results of 

 Borne of his photometrical work on the small 



planets : Volume in millions 



of cable kilometre*. 



Vesta, 6-5 magnitude 32 2 



Cer.-s, 7 7 " 21 S 



Pallas, S-5 " 64 



Hygeia 4-:; 



Eunomia 4 -3 



Juno 8'7 



Hebe J I 



Iris 24 



Psyche 21 



Lutetia 1'J 



The total volume of the ten largest asteroids, 

 therefore, is 81 '5 millions of cubic kilometres; 

 that of the first seventy, Prof. Peters found to 

 be 127'74; and as the volume of the earth is 

 1,082,841 millions of cubic kilometres, the com- 

 bined volumes of the first seventy asteroids is 

 to that of the earth as 1 to 7,862. 



Prof. Daniel Kirk wood has published re- 

 cently an exceedingly interesting work of sixty 

 pages on " The Asteroids or Minor Planets 

 between Mars and Jupiter." This gives, among 

 other items of interest, the asteroids in the or- 

 der of discovery, to and including No. 271, 

 the elements of the asteroids, theories in re- 

 gard to the origin of asteroids, etc. The fol- 

 lowing asteroids have been discovered since 

 the table in the " Annual Cyclopedia " for 

 1887 was prepared : 



Comets. Six comets were discovered in 1888 

 up to November 1. Comet I was discovered 

 early in the morning of February 19, by Mr. 

 Sawerthal as he was returning from the 



