xxxii President'' s Address. C^^g* ^9, 



Whitney, Langley was also enabled to calculate the effect of the 

 earth's atmosphere in absorbing the different portions of the spectrum, 

 and he found that the blue end suffered far more than the red. The 

 solar atmosphere has been shown by Vogel and Langley to have a 

 similar effect in stopping the rays of shorter vibration, so that our 

 view of the Sun is as if two plates of red glass were interposed 

 between us, the removal of which might leave the Sun of a bluish 

 colour. 



Photographs of the Sun's disc are taken on every fine day at 

 Greenwich, Mauritius, and at Dehra Dun in India ; so that it rarely 

 happens that there are more than two or three days in the year on 

 which we have not a record of the state of the disc and of the size 

 and shape of the spots on it. 



The study of the chromosphere and the solar prominences has been 

 carried on by many observers, among whom the late Director of the 

 Rome Observatory, Tacchini, deserves particular mention. It cannot 

 be said that any striking result has been reached in connection with 

 them, but a sound foundation is being laid for future investigation. 



Total Eclipses of the Sun have been regularly and systematically 

 observed, expeditions being despatched to any part of terra firma 

 where they may be visible, as at -present it is only on these occasions 

 that Ave can see that wonderful solar appendage — the corona. The 

 appearances presented by the corona are very different in different 

 eclipses, and there is a large amount of evidence to show that it is 

 most developed at times of sun-spot minima. 



The Eclipse of 1878 way particularly well observed in North 

 America, in one case at an altitude of 14,100 feet above the sea-level, 

 and the great advantage of observing at high altitudes was shown by 

 the fact that the corona was visible for ^^ after totality. 



The brighter part of the corona was reduced to a narrow ring of light 

 round the Sun, but remarkable fainter streamers were seen stretching 

 away right and left of the Sun to a distance of ten millions of miles. 

 The axis of the longest ray coincided with the ecliptic. The idea of 

 a connection between these streamers and the zodiacal light imme- 

 diately suggested itself, and in fact we should expect the zodiacal light 

 (which is certainly a solar appendage) to present much the same 

 appearances at its lower parts as were seen in this eclipse. I may 

 mention that a very similar appearance was seen by Stone in Nama- 

 qualand in 1874, but the rays were not visible so far from the Sun's 

 -disc. Next in importance was the eclipse of May 17, 1882, the chief 



