The total solar Eclipse of August 30, 1905 401 



outer portion, which furnished the unexpected amount of 

 light which persisted through totality. It is clear that 

 if the inner portion, having a width of 45", had been 

 uncovered, the daylight during totality would have been 

 still more remarkable. 



In this respect there was a great contrast between the 

 eclipse of this year and that of May 17, 1882, which I wit- 

 nessed at Sohag, on the Nile, where a large camp of 

 astronomers of many nations was established. In it, one 

 of the most striking features was the rapid darkening during 

 the last moments before second contact. I have always 

 compared it to what is witnessed when a lecture-room is 

 darkened during the day by quickly closing the shutters of 

 the windows in succession. .In 1882 the darkening took 

 place rapidly and completely ; and immediately quite a 

 number of stars came out, besides the great comet which 

 revealed itself, all unsuspected, close to the sun's limb, and 

 formed the feature of that eclipse which was most noticed 

 and is best remembered by the spectators. In 1905 the 

 darkening effect was much less striking ; but the illustration 

 of the lecture-room holds if we imagine that the shutter of 

 the last window is out of order and has to remain open 

 during the demonstration. 



The contrast between the two eclipses is accentuated 

 when we remember that the apparent semi-diameter of the 

 moon, as seen from Torreblanca, was 45" greater than that 

 of the sun, while on the Nile this excess was only I5"'4. 

 Therefore a width of 45" of the brightest part of the corona 

 was eclipsed in 1905, as against only I5"'4 in 1882. If, there- 

 fore, the uneclipsed coronas had possessed equal efficiency as 

 furnishers of daylight, the darkness during totality ought to 

 have been much greater in 1905 than it was in 1882; but 

 the opposite was the case. Therefore, whatever may be 

 the process by which the inner corona or luminous ring is 

 produced, it was much more active on August 30, 1905, than 

 it was on May 17, 1882. 



