Sepiejibee 16, 1898.] 



SCIENGE. 



347 



sequently found also on the African and 

 Brazilian plates, taken by the English and 

 American astronomers. This object was in 

 motion away from the sun, as shown by the 

 photographs, which covered an interval of 

 2 hours and 36 minutes of absolute time. 

 Professor Schaeberle believes this was a 

 comet. It is not impossible, however, that 

 it was a mass of coronal matter moving out 

 from the sun, such as has been shown by 

 the spectroscope frequently to occur in the 

 case of solar prominences. The fact that 

 the object seemed to be connected with the 

 sun by a coronal streamer would rather 

 favor the explanation. The drawing given 

 in Astronomy and Astro-Physics, p. 307, Vol. 

 XIII., seems to further support this idea. 



During the solar eclipse of 1896 the sky 

 was cloudy at nearly all the stations, and 

 especially where the most elaborate prepara- 

 tions had been made for photographic work. 

 A few photographs were obtained, however, 

 some of which, with very small lenses, 

 showed the coronal extensions to a great 

 length. Mr. Burckhalter, of Oakland, Cal., 

 had arranged an ingenious device for grad- 

 ing the exposures of the Corona. Clouds 

 unfortunately prevented the trial of this 

 experiment. The most important photo- 

 graphic work at this eclipse was the photo- 

 graphing of the flash spectrum, or the mo- 

 mentary reversal of the Fraunhofer lines 

 which occurs when the edge of the sun 

 disappears behind the moon or reappears 

 from it, and for an instant exposes the 

 reversing layer, which was first seen by 

 Professor Young at the eclipse of 1870. 

 This extremely important picture was made 

 by William Shaokleton, a young English- 

 man, who patiently waited and watched the 

 spectrum at the edge of the sun, and at the 

 instant of the reversal of the lines exposed 

 a plate which caught, for the first time, the 

 fugitive bright lines which are only visible 

 for about a second. This photograph was 

 a triumph for photography, for the record 



of the phenomenon now does not rest upon 

 the authority of any hasty observations, 

 but remains a permanently visible record. 



Our record closes with the eclipse of Jan- 

 uary 22, 1898, which was photographed in 

 India by American and English astronomers. 

 The photograph of the flash spectrum was 

 successfully repeated by many observers. 

 The coronal extensions were carried to a 

 greater extent than at any previous eclipse, 

 by photographs secured with a very small 

 lens by Mr. and Mrs. Maunder. 



In speaking of the photography of the co- 

 rona it is well to mention the extremely in- 

 eresting experiments of Dr. Huggins in an 

 endeavor some years ago to photograph it 

 without an eclipse. By the use of absorbing 

 media, and later with extremely short expo- 

 sures, he obtained very corona-like appear- 

 ances, and it is not yet certain that they were 

 not true coronal forms. Such experiments 

 should be tried at very high altitudes in a 

 pure atmosphere, and it is to be hoped that 

 these efforts will be again undertakenunder 

 more favorable conditions. 



The transit of Venus across the sun's disc 

 in 1882 was very successfully photographed, 

 and the measures of the pictures made by 

 the Americans has given a good redetermi- 

 nation of the solar parallax. A fine series 

 of photographs of this transit with wet 

 plates was obtained by Professor D. P. 

 Todd at the Lick Observatory. This was 

 six years before the completion of the Ob- 

 servatory. 



There is no question but that Janssen, of 

 Meudon, succeeded many years ago in 

 making the best photographs of portions of 

 the sun's surface that have yet been made. 

 These pictures show the granulation of the 

 solar surface and the details of the sun 

 spots with admirable clearness. Janssen 

 has always used the old wet-plate process, 

 which seems to give the best results in 

 solar work. The instrument with which 

 his work is done is a very crude afi&ir. The 



