ASTRONOMY, PROGRESS OP, IN 1894. 



lowing brief resume will give the reader an idea 

 of what has been accomplished in the various 

 branches into which astronomy has been di- 

 vided. 



The Sun. Prof. George E. Hale, of Kenwood 

 Observatory, Chicago, and a few other students 

 of solar physics, have made of late herculean ef- 

 forts to photograph the solar corona without an 

 eclipse. Mr. Hale has recently returned from a 

 visit to the principal observatories of the Old 

 World, one object of his journey being to test 

 this apparatus I'rom the summit of Mount Etna, 

 Mn Sicily. 9,652 feet high, after having vainly 

 tried to 'secure the corona's photograph from the 

 summit of Pike's Peak, in Colorado, an altitude 

 of 14,147 feet. He was not successful in secur- 

 ing the desired photograph. Work on this line 

 had previously been done by Dr. Common, of 

 England, who felt for a time that he had secured 

 the desired imprint, but critical examination of 

 the plates showed the coronal appearances to be 

 due to some terrestrial effect. 



During the progress of the solar eclipse of 

 1886 photographic exposures revealed a false 

 corona, part of which was in front of the moon, 

 showing that it was produced by some unknown 

 terrestrial phenomenon. 



Oxygen in the Sun. This question has been 

 much discussed by astronomers, and the pre- 

 ponderating evidence seems to be that this ele- 

 ment is lacking. There are three different spec- 

 tra of emission believed by spectroscopists to 

 belong to oxygen viz., the two-line spectra, the 

 one-band spectrum, and a continuous spectrum. 

 In the spectrum of the sun neither the line nor 

 the band spectrum has been found, and the con- 

 tinuous spectrum of the sun has at least not been 

 proved. What has hitherto been believed to 

 have been its detection has been shown by M. 

 Janssen to belong wholly to the earth's atmos- 

 phere, and he finds that the evidence of its ex- 

 istence disappears when the sun is observed 

 from greatly elevated stations, notably from his 

 improvised observatory on Mont Blanc, Switzer- 

 land. But it seems surpassingly strange, when 

 we consider that more than half of the earth, in- 

 cluding its air, land, and water, is composed of 

 oxygen, that this substance should be entirely 

 absent from the parent orb. 



Sun Spots. Many of the sun spots of 1894 

 have been of enormous size, indicating the con- 

 tinuance of maximum sun-spottedness. Those 

 visible from Feb. 16 to Feb. 38 were nearly as 

 large as any ever recorded, and evoked universal 

 interest. On the 21st the group of spots was 

 easily seen by the naked eye, having attained to 

 2,000,000 square miles in extent. As confirma- 

 tory or otherwise that aurora? and magnetic 

 earth currents are produced by these solar out- 

 bursts, and as showing what part of the sun's 

 disk produces spots exercising the greatest in- 

 fluence on the earth, it may be said that the 

 great spot just considered furnishes no positive 

 proof that the effects often observed are at all 

 connected with sun spots. While many astron- 

 omers hold the opinion that sun spots cause 

 magnetic disturbances on the earth and in its 

 atmosphere, and produce the aurora borealis, 

 others strenuously contend that all the above 

 phenomena are as frequently observed in the 

 absence of sun spots as when they are present. 

 VOL. xxxiv. 4 A 



The largest sun spot observed thus far in 1894 

 appeared on the eastern limb of the sun Au#. 10, 

 passed the sun's center on the 16th, and disap- 

 peared on the western limb, by the sun's rota- 

 tion, on Aug. 23, having gone through many 

 changes of form. Though not comparable in 

 size to many that have occasionally been viewed, 

 yet its magnitude on the 15th was enormous, 

 equaling one tenth of the solar disk, or 86,000 

 miles in length and 40,000 in width, covering an 

 area of over 8,000,000,000 square miles. On 

 Sept. 5 this group reappeared, by rotation, on 

 the sun's eastern limb, though greatly dimin- 

 ished in size, and it was lost to view on the 15th. 



Venus and Mercury. The study of the secu- 

 lar variations of the orbits of the four inner plan- 

 ets, as derived from observation, has led Prof. 

 Simon Newcomb to the conclusion that the peri- 

 helion of Mercury is not the only element the secu- 

 lar variation of wtyich can not be satisfactorily de- 

 termined by existing theory. The motion of the 

 node of Venus can not be explained except by sup- 

 posing errors of observation which do not seem 

 admissible, while the motions of the eccentricity 

 and node of Mercury also deviate suspiciously 

 from the results of any probable values of the 

 masses of the disturbing planets. These anomalies 

 can not be simultaneously explained by an intra- 

 mercurial zone of planets, by the action of mat- 

 ter reflecting the zodiacal light, nor by a devia- 

 tion of gravitation from the usually accepted 

 law. The uncertainty as to the mass of Mercury 

 makes the construction of a working hypothesis 

 difficult. That one which best represents ob- 

 servations is that of a ring of planetoids, of 

 small eccentricity, a little outside of the orbit 

 of Mercury, and a little more inclined to the 

 ecliptic. 



Mars. Prof. Campbell, of Lick Observatory, 

 has compared the spectrum of Mars with that of 

 the moon, when the two objects were in close 

 proximity, and has found the two spectra identi- 

 cal that is to say, it is in both cases the spec- 

 trum of the sun unmodified by passage through 

 an atmosphere. As, therefore, the moon is with- 

 out an atmosphere, and as her spectrum is identi- 

 cal with that of the sun, he infers that if Mars 

 has an atmosphere it is too rare to be spectro- 

 scopically noticeable. Though his conclusions 

 seem unassailable, yet they do not meet with 

 general acceptance, as telescopic examination 

 shows an atmosphere of considerable density. 



The spectroscopic studies of Mars by Hug- 

 gins, Rutherfurd, Vogel, and Secchi all show, 

 in addition to numerous lines of the solar spec- 

 trum, that bands were present toward the red 

 end of the spectrum which did not belong to 

 the spectrum of the sun. but which were coinci- 

 dent with the terrestrial-absorption spectrum. 

 Furthermore, the telescope reveals the presence 

 of clouds and of snow, which certainly could not 

 exist without an atmosphere. 



The most interesting features of the planet 

 Mars are the white caps that appear alternately 

 at his poles. Generally they are visible with 

 small telescopes, and exhibit a strong contrast 

 with the reddish tone of the planet. Strangely 

 enough, at this writing, Nov. 1, neither is to be 

 seen with the 16-inch refractor of Lowe Ob- 

 servatory, Echo Mountain, California. They fur- 

 nish valuable evidence regarding the physical 



