THE PHOTOSPHERE AND SUN-SPOTS, 535 



Any one, for instance, who has looked down upon the Mediter- 

 ranean from the summit of Gibraltar or Capri, aud can recall its curi- 

 ous unlikeness to its familiar aspect — its apparent stillness, the faint 

 intricate bands of white and gray, which, thus seen, overlap it like a 

 net-work of broad veins, and the strangely permanent patterns left by 

 the foam, which are entirely lost to us as we approach its tossing sur- 

 face — will have a not wholly inadequate idea of the first impression 

 made by the sight of the photosphere. If we bring ourselves nearer, 

 as it were, by an increase of magnifying powder, w^e lose sight of the 

 larger masses of light and shade, whose place is filled by a curious 

 mottling of faint, inextricably confused, and intermingled moss-like 

 patterns. 



With the best optical aid, and in those rarer moments when our 

 own atmosphere is comparatively tranquil, we discern that the whole 

 of these cloud-like mottlings are composed of very minute definite 

 oval forms, which have been compared to grains of rice. 



Minute as they appear, their real size is very great ; for, though in 

 a large telescope they seem mere dots, the average area of each is cer- 

 tainly much over 100,000 square miles. Since we see them at all, it 

 must be owing to some inequality of brightness which distinguishes 

 them, and, in fact, they do not seem to be in absolute contact, but 

 present rather the appearance of numberless little w^hite clouds, ar- 

 ranged with a sort of order upon a background of darker sky, or, if 

 we compare them to rice-grains, we may suppose the grains arranged 

 in rude tesselated patterns upon a gray cloth. 



The most extraordinary conjectures have been hazarded as to the 

 real nature of these objects, which are of somewhat recent discovery, 

 and which are so difficult of observation that few have distinctly seen 

 them. Whatever these things may be, they are the principal source 

 of the sun's light, and presumably of its heat, and this adds to the in- 

 terest of their study. 



The writer has given a considerable time to their observation, 

 which can only be carried on successfully by patient waiting, and the 

 employment of those scattered moments when the ever-perturbed at- 

 mosphere of the earth is relatively still. He has been led to conclude 

 that these bodies are composed of still smaller forms, and that their 

 total area is inconsiderable compared with that of the whole sun, for, 

 though it is almost impossible to determine the aggregate space occu- 

 pied by such minute things, the writer has been led to conclude that it 

 can hardly exceed one-fifth of the solar surface, and may be much less. 

 An inconsiderable part only of the solar light comes from the relatively 

 dark background on which they appear, and, in reference to these still 

 mysterious things, we may, then, partly adopt an expression which 

 Huyghens used with regard to the faculse, and say that there is 

 indeed in the sun ^^ something brighter than the sun itself.'*'* The 

 expression will not appear a forced or exaggerated one if we reflect 



