THE ECLIPSE OF 1878. 137 



occasions. Its brightness was estimated by Mr. 

 Lockyer as exceeding tenfold that of the corona seen in 

 1871. It was comparatively simple in structure, show- 

 ing only in two places indications of definite structure 

 close to the sun. Several long rays were seen, how- 

 ever, and I shall look forward with extreme interest 

 to the evidence obtained respecting these features. 1 

 For it appears that the doubts which I had supposed 

 * no longer entertained ' respecting the corona, though 

 dismissed of necessity as regards all the complicated 

 details photographed in 1871, still linger as regards 

 the long straight rays, which did not appear on that 

 occasion and naturally were not photographed. The 

 resemblance between these rays and those seen in 

 Secchi's ( hole in a shutter ' experiment leads some to 

 imagine that, like the latter, the former are produced 

 by the sun's light shining on matter nearer to the eye 

 than the interposed dark object the irregular * stopper ' 

 in Secchi's experiment, the moon in the case of a total 

 eclipse. In reality the rays cannot be thus explained, 

 unless we assume that our atmosphere or some other 

 matter capable of reflecting light extends as far as the 

 moon, which few will consider probable. I believe 

 that the observations made on this occasion, and espe- 

 cially the photographs of the corona, will dispose 

 definitely of these last remaining doubts respecting 



1 These were observed by Professor Cleveland Abbe extending to a 

 distance of at least five millions of miles from the eclipsed sun, and 

 from their appearance and changes of appearance it was clear that they 

 were due to meteoric streams near the sun. See further the essay OH 

 ' The Earth in Meteoric Shadow ' which follows. 



