20 LIGHT SCIENCE FOR LEISURE HOURS. 



of these gigantic land-masses. Yet the highest peaks 

 of the Alps are little more than fifteen thousand feet 

 above the sea-level. Imagine, then, the magnificence 

 of glowing masses twenty-five thousand miles above 

 the mean level of the sun's surface. 



During the eclipse of 1860, the red prominences 

 again attracted a great deal of attention among astro- 

 nomers. It will be remembered that many leading 

 English astronomers, amongst whom the Astronomer 

 Koyal again figured, took part in the celebrated Hima- 

 laya expedition. MM. Leverrier and Groldschmidt of 

 Paris, the Padre Secchi of Home, and a host of astro- 

 nomical celebrities, took part in observing the various 

 phenomena, astronomical, physical, and meteorological, 

 which attended the totality of this important eclipse. 



It is interesting, in the first place, to compare Sir 

 Greorge Airy's impressions as to the general effect of 

 the totality with those which he formed during the 

 two former eclipses. It is not often that the same 

 observer and that observer so skilful and eminent 

 has the opportunity of contrasting together three total 

 eclipses of the sun. In fact, I doubt very much 

 whether any similar case is on record. Hence, a 

 peculiar value attaches to Sir Gr. Airy's remarks. ' On 

 the progress of the eclipse,' he says, ' I have nothing 

 to remark, except that I thought the singular darken- 

 ing of the landscape, whose character is peculiar to an 

 eclipse, to be sadder than usual. The cause of this 

 peculiar character I conceive to be the diminution of 

 light in the higher strata of the air. When the sun is 



