ON THE SOLAR CORONA. 761 



it is obvious the rift might have gone round with the sun, but there is 

 no positive evidence on this point.*] 



As the comparison of the English plates with those taken at Caroline 

 Island possesses great interest, I think it well to put on record here a let- 

 ter written by Mr. Lawrence to Professor Stokes, dated Sept. 14, 1883 : 



"Dr. Huggins called upon Mr. Woods this morning and showed us 

 the drawings Mr. Wesley has made of his coronas. He told us that 

 he particularly did not wish to see our negatives, but that he would 

 like us to compare his results with ours. We did so, and found that 

 some of the strongly marked details could be made out on his drawings, 

 a rift near the north pole being especially noticeable ; this was in a 

 photograph taken on April 3d, in which the detail of the northern 

 hemisphere is best shown, while the detail of our southern hemisphere 

 most resembles the photograph taken on June 6th ; in fact, our nega- 

 tives seem to hold an intermediate position. Afterward I went with 

 Dr. Huggins and Mr. Woods to Burlington House to see the negatives. 

 The outline and distribution of light in the inner corona of April 3d 

 are very similar to those on our plate which had the shortest exposure ; 

 the outer corona is, however, I think, hidden by atmospheric glare. 

 As a result of the comparison, I should say that Dr. Huggins's coronas 

 are certainly genuine as far as 8' from the limb." 



Though the plates which were obtained during the summer of 1883 

 appeared to be satisfactory to the extent of showing that there could 

 be little doubt remaining but that the corona had been photographed 

 without an eclipse, and therefore of justifying the hope that a success- 

 ful method for the continuous investigation of the corona had been 

 placed in the hands of astronomers, yet, as the photographs were taken 

 under the specially unfavorable conditions of our climate, they failed 

 to show the details of the structure of the corona. 



The next step was obviously to have the method carried out at 

 some place of high elevation, where the large part of the glare which 

 is due to the lower and denser parts of our atmosphere would no longer 

 be present. I ventured to suggest to the Council of the Royal Society 

 that a grant from the fund placed annually by the Government at 

 the disposal of the Royal Society should be put in the hands of a 

 small committee for this purpose. This suggestion was well received, 

 and a committee was appointed by the Council of the Royal Society. 

 The committee selected the Riff el, near Zermatt in Switzei'land, a sta- 

 tion which has an elevation of 8,500 feet, and the further advantages 

 of easy access, and of hotel accommodation. The committee was 

 fortunate in securing the services, as photographer, of Mr. Ray Woods, 

 who as assistant to Professor Schuster had photographed the corona 

 during the eclipse of 1882 in Egypt, and who in 1883, in conjunction 

 with Mr. Lawrence, had photographed the eclipse of that year at 

 Caroline Island. 



* See Plates XI and XIa, "British Association Report," 1S83, p. 348. 



