Septembee 16, 1898.] 



SCIENCE. 



345 



than the wet plates, which doubtless pre- 

 vented their being used for the corona. 



Though the pictures of 1870 and 1871 

 showed the value of the photographic 

 method, it had so far failed to show the 

 greater and fainter extensions of the cor- 

 ona. In speaking of the eclipse of 1871 

 and the success attained by photography at 

 that time, it is well here to mention the 

 evil influence that the old method of draw- 

 ing had upon at least one observer. A Mr. 

 Holiday had made observations of the cor- 

 ona from a housetop, and thus describes 

 the result in his report: "As soon as the 

 eclipse was over, I came down from the 

 roof and plunged my head into cold water, 

 for I was violently excited, and before 

 breakfast I had made three drawings from 

 my memoranda." If photography has done 

 nothing more for astronomy than to prevent 

 occurrences of this kind it would at least de- 

 serve lasting respect from a humane point 

 of view. 



In 1878 extensive preparations were 

 made to observe the eclipse of July 29th of 

 that year. Photography was to play an 

 important part, though astronomers did not 

 rely very strongly upon it, for it appears 

 that all were prepared to make the custom- 

 ary drawings of the corona, and unfortu- 

 nately each person faithfully carried out 

 that purpose. A most suggestive illustra- 

 tion of the uncertainty of such work is 

 found in the large collection of drawings 

 published in a volume issued by the United 

 States government relating to the eclipse 

 of 1878. An examination of these forty or 

 fifty pictures shows that scarcely any two 

 of them would be supposed to represent the 

 same object, and none of them at all 

 closely resembled the photographs. The 

 method of free-hand drawing of the corona 

 made under the attending conditions of a 

 total eclipse received its death-blow at that 

 time, for it showed the utter inability of 

 the average astronomer to sketch or draw 



under such circumstances what he really 

 saw. 



At this time the dry plate was still in its 

 infancy, and the results with it ranged from 

 failure up to a fair picture of the corona. 

 The greatest extension of the corona ob- 

 tained, however, seemed to be about half a 

 degree from the moon's limb, while Profes- 

 sors Newcomb and Langley traced it nearly 

 six degrees with the eye alone. The re- 

 sults, nevertheless, were highly important, 

 and they demonstrated the success of pho- 

 tography for this class of work. 



One of the cameras at this eclipse was 

 put in charge of a private soldier, with 

 instructions to give an exposure of 65 

 seconds. The instructions were faithfully 

 carried out, but as no one had told him to 

 draw the dark slide the plate remained un- 

 exposed. 



The total eclipse of 1882 proved to be of 

 special interest, from the fact that a small 

 unknown comet was then in the immediate 

 neighborhood of the sun, and was seen 

 with the naked eye during the eclipse. 

 The increased sensitiveness of the plates 

 then in use secured a strong impression of 

 this object. The known history of the 

 comet is comprised within the few minutes 

 of totality of that eclipse, for it was never 

 seen afterwards. 



In the eclipse of 1886 photography again 

 held an important position. But the ex- 

 tremely humid climate of Granada (one of 

 the observing stations) and the necessity of 

 employing volunteer observers led to numer- 

 ous disasters, such as the failure to get the 

 sun's image on the sensitive plate in the 

 most important instrument ; the breaking 

 of the polar axis j ust before totality in the 

 next important instrument ; the failure of 

 an assistant to make the exposures with 

 another until totality was all but over ; the 

 fact that two native policemen stood in 

 front of the photometer during totality ; the 

 two weeks' delay of the steamer in getting 



