August 3, 1900.] 



SCIENCE. 



177 



and we took a very good series ef pictures, 

 showing a vast amount of detail clear down 

 to the sun. We have learned much of what 

 ought to be done in the future. Eclipse 

 problems are constantly changing and new 

 methods are used. In the adjustment of 

 the frame in position, I think it ought to 

 be done by actual observation of the stars, 

 rather than by experiment. We happened 

 to get our carriage some inches out of place, 

 but by our observations we brought it with- 

 in 1-1 6th of an inch of its true place. We 

 may study the photographs as to the forms 

 of the filaments, and the relations of the 

 chromosphere to the protuberances ; but 

 that ought to be supplemented by visual 

 observations with the telescope. A six- 

 inch telescope with a magnifying power of 

 50 will show us ten times as much as can 

 be seen in the best photographs. But the 

 observer sees it and no one else, so that 

 we still need the photographs. The plates 

 were exposed by Mr. Mayo, who had him- 

 self constructed the apparatus. Mr. Morgan 

 had a four-inch equatorial, and I used a 

 six-inch equatorial and observed visually. 

 It was our purpose to examine each of the 

 prominences in succession to see if we could 

 perceive any distortion. We could see no 

 relation to the protuberances, and our visual 

 observations simply confirmed what was 

 shown in the photographs. At the eclipse 

 of 1878 the filaments were well seen, and 

 each one stood out distinctly. At this 

 eclipse there was not that sharpness, and 

 there seemed to be a strong background of 

 something else to the equatorial filaments. 

 In 1878 at the poles the rays were very 

 much as in this eclipse. In the equatorial 

 region there was a perfect network of 

 filaments. They started out and moved 

 right back with an incurvature in the op- 

 posite direction, so that there were a num- 

 ber of filaments side by side. They are 

 certainly not hyperbolic curves, but we do 

 not know what they are. One suggestion 



is that they are meteoric or comet streams. 

 Our exposures were mostly short ; we had 

 nothing exceeding 12 seconds. It would 

 seem well to have some longer exposures. 

 I am glad the Naval Observatory has se- 

 cured a plate with a longer exposure, on 

 which we can see longer filaments and learn 

 more of the nature of the curve. By trac- 

 ing the curve back to the sun's surface we 

 may be able to get some idea of its form. 

 We had a number of small cameras mounted 

 on a polar axis and managed by Mr. Lyon, 

 and with these we used a color screen such 

 that the green line was not seen, but on 

 an open space. I think in another eclipse 

 we ought to get more color screen pictures 

 with our large cameras. 



Mr. C. C. Abbott presented a report of 

 observations at Waynesborough. 



Mr. Dorsey explained the mode of deter- 

 mining the polarization of the bright 

 coronal lines. 



The Secretary read the following reports 

 from Edwin A. Frost and E. E. Barnard 

 upon their observations of the eclipse made 

 at Wadesboro, IST. C. 



E. B. Frost. Four spectroscopes were 

 employed : 1. A small plane grating in 

 front of a lens of 2-inch aperture and 20- 

 inch focus, for visual use in determining 

 proper instant for exposure for obtaining 

 ' flash ' spectra. 



2. Train of 3 large flint prisms, at mini- 

 mum deviation for i 4230, in front of pho- 

 tographic lens of 3^-inch aperture and 

 42-inch focus ; for photographing flashes 

 and cusps and coronal spectra. 



3. Small concave grating used directly, 

 without slit ; focus 30-inch for photograph- 

 ing flash spectra. 



4. Large plane grating of 20,000 lines to 

 inch, in front of visual lens of 3^-inch 

 aperture, 42-inch focus, with red screen, 

 for photographing red end of spectrum of 

 cusps, flash and corona. All placed in hori- 

 zontal beam 13-inch diameter reflected from 



