THE SUN S SPOTS. 87 



spots exert any slight miluence on our atmosphere, my tables 

 would, perhaps, rather tend to show that the years which 

 exhibit a larger number of spots had a smaller number of 

 fine days than those exhibiting few spots." (Schum., Astron. 

 Nachr. ,^o. 638, § 221.) 



" William Herschel named the brighter streaks of light 

 which are seen only toward the Sun's circumference, facidce, 

 and the vein-like streaks visible only toward the center of the 

 Sun's disk, shallows (Astr. Nachr., No. 350, p. 243). I am 

 of opinion that the faculce and shallows are both derived 

 from the same conglobate luminous clouds, which appear 

 more intensely bright at the circumference, but, being less 

 luminous in the center of the Sun's disk than the surface, 

 exhibit the appearance of shallows. I think it preferable to 

 designate all the brighter portions of the Sun as luminous 

 clouds, dividing them, according to their form, into globate 

 and vein-like. These luminous clouds are irregularly dis- 

 tributed over the Sun, and when more strongly manifested 

 occasionally impart a mottled or marbled appearance to the 

 disk. This is often distinctly visible over the entire circum- 

 ference of the Sun, and sometimes even to its poles, but yet 

 always most decidedly manifested in the two proper zones 

 of the spots, even when no spots are visible in those regions. 

 At such times these bright zones of Sun-spots vividly remind 

 one of Jupiter's belts. 



" The fainter portions lying between the vein-like lumin- 

 ous clouds on the general surface of the Sun are deeper in- 

 dentations, and always present a shagreen-like gray, sand- 

 like appearance, reminding the observer of a mass of uni- 

 formly-sized grains of sand. On this shagreen-like surface 

 we may occasionally notice exceedingly small faint gray (not 

 black) pores, which are further intersected by very delicate 

 dark veins. (Astr. Nachr., No. 473, p. 28G.) These pores, 

 when present in large masses, form gray nebulous groups, 

 constituting the penumbrsB of the Sun-spots. Here the pores 

 and black points may be seen spreading from the nucleus to the 

 circumference of the penumbra, generally in a radiating form, 

 which occasions the identity of configuration so frequently ob- 

 served to exist between the penumbra and the nucleus." 



The signification and connection of these varying phenom- 

 ena can never be manifested in their entire importance to 

 the inquiring physicist until an uninterrupted series of repre- 

 sentations of the Sun's spots* can be obtained by the aid of 

 * Sir John Herschel, Observations at the Cape, p. 434. 



