166 SOME RECENT ASTRONOMICAL EVENTS. 



more complete, though the night of Msw 18 was, as I have said, gener- 

 ally line, yet when he tried as a last attempt to make a long exposure 

 on the rifts in the southern Milky Way, the very regions he wished 

 most to get ])ecame covered with a slight degree of fog which spoiled 

 the definition. 



The other parties on the island all fared better than we; but only 

 one, the branch of the Naval Observatory expedition which was 

 located at Fort de Kock, close to the northern edge of the shadow, 

 had perfect seeing. There excellent photographs of the corona and 

 prominences were secured w4th the 40-foot instrument, under Mr. 

 Peters's charge, and spectroscopic results of value Avere obtained with 

 the grating in the hands of Dr. Humphreys. Dr. Mitchell, at Sawah 

 Loento, was successful in spite of clouds. He secured a fine photo- 

 graph of the '■"tiash spectrum" at third contact, which gives much 

 information in regard to the sun's atmosphere. The large Dutch party 

 had but very unsatisfactory results, as the cloudiness was almost equal 

 to that at Solok. The main portion of the English expedition, occu- 

 pying a small island just off the west coast of Sumatra, had, though 

 not a cloudless, yet a not very cloudy sky, and obtained excellent 

 results, of which a short account has lately appeared. 



Mr. Perrine, of the Lick Observatory, was pretty successful, consid- 

 ering that he also observed through a very considerable cloudiness, 

 though not equal to that at Solok. His intramercurial planet appara- 

 tus revealed possilily thirty or forty stars, where it would have shown 

 perhaps a thousand had the sky been clear; but with his direct photo- 

 graphs and with his spectroscopic work he was much more successful. 

 In a preliminary report from the Lick Observatory it appears that he 

 has obtained good photographs of the coronal spectrum extending to 

 considerable distances each side of the sun, and taken with slit spectro- 

 scopes with the slit both tangential and radial to the sun's limb. 



In each of these the outer but not the inner corona was shown to 

 have faint Fraunhofer absorption lines in the spectrum, giving, in other 

 words, a reflected solar spectrum, thus proving that a portion at least of 

 the coronal light is reflected from particles. His spectrum photo- 

 graphs, however, show in addition that the major part of the coronal 

 light is probably not reflected, and he attributes it to the incandescence 

 of particles heated by their proximity to the sun. This view, some 

 readers may recall, would be in contradiction to that tentatively 

 advanced from considerations of the bolometric experiments of the 

 Smithsonian Institution at Wadesboro, North Carolina, in 1900, which 

 yielded the inference that the inner corona was relatively a cool source 

 of light assimilable to the glow discharge or to the aurora. I can not 

 altogether understand wh}^ it is that Mr. Perrine so positively pro- 

 nounces the radiation of the inner corona that of an incandescent body 

 rather than that of an electrical discharge or something of a similar 



