96 THE CHEMISTRY OF THE SUN. [CHAP. 



being more remarkable thereabout than elsewhere, though 

 everywhere traceable in good observing weather. Faculse may 

 be of all magnitudes, from hardly visible softly gleaming 

 narrow tracks, 1,000 miles long, to continuous complicated and 

 heapy ridges 40,000 miles and more in length, and 1,000 to 

 4,000 miles broad. Eidges of this kind often surround a spot, 

 and hence appear the more conspicuous ; but sometimes there 

 appears a very broad white platform round the spot, and from 

 this the white crumpled ridges pass in various directions. 



So far we have referred only to the phenomena at all times 

 visible to us with ordinary telescopic aid, but those who have 

 been favoured by a sight of a total eclipse, and many more who 

 have read the accounts of total eclipses, know that there is a 

 great deal more of the sun than one generally sees. On these 

 occasions a part of the sun not usually visible its external 

 atmosphere is unveiled for us. The central light of the sun 

 being cut off by the intervening dark moon, surrounding it, on 

 all sides, appears a glorious halo, generally of a silver-white 

 light ; this is called the corona ; now radiated in structure, and 

 again full of strangely- curved markings or long streamers, it 

 extends sometimes beyond the moon to a distance equal to 

 many diameters. 



Eecent eclipse work has shown that the corona, in part, at all 

 events, reveals to us the sun's outer atmosphere, which is in- 

 visible when the sun's light itself is present, owing to the over- 

 powering light of the latter. But the corona is not all we see at 

 such times. 



When the totality has commenced, apparently close to the edge 

 of the moon, and therefore within the corona, are observed fantas- 

 tically-shaped masses generally full lake-red, fading into rose- 

 pink in colour, variously called red flames or red prominences. 



The height of some of these prominences exceeds 70,000 

 miles. They were first described by Stannyan in 1706. Since 

 his time many have held them to be beautiful effects produced 



