39 



photosphere, cooled in the space in which they are projected from 

 a white heat to a red one. 



The spectroscope has determined for us their constitution ; 

 they are almost wholly incandescent hydrogen gas. No grander 

 example of their magnitude and splendour has been seen, perhaps, 

 than the one which Major Tennant succeeded in photographing. 

 We will now throw on the screen a copy of the picture he took 

 You see there that enormous column of flame which rises to a 

 height of 80,000 miles. But the structure of it is also very re- 

 markable. Before you is now a representation of it on a larger 

 scale, and the spiral form of it bears witness to the direction of 

 the enormous force which hurled it upwards into the space. You 

 will remember also the spiral cyclonic form which has been noticed 

 in the sun-spots. But the forms of these fiery clouds are manifold. 

 They are for ever changing. They have the tongue-like motion 

 of a flame swaying backwards and forwards as at a great con- 

 flagration. Jets rising up as from a fountain, and bending back 

 again to the sun as in those drawings of them now before you. 

 Again they transform themselves into semblances of trees and 

 bushes, and into shapes as fantastical as the widest fancy can 

 imagine. Of the thousands Avhich Eespighi lias mapped and 

 figured, I vrill but shew you a few as an example of these singular 

 forms. This portion of the sun's atmosphere has been termed from 

 the colour which it displays the chromosphere. This we are pre- 

 vented from seeing except in eclipses, by reason of the strong light 

 emitted by the sun. But the sun's atmosphere does not end here. 

 The strange and beautiful light of luminous gas extending far into 

 space and taking sometimes a strange configuration had been 

 noticed surrounding the ecUpsed sun. This more rarified portion 

 of the sun's atmosphere has been termed the Corona.. 



The five Aaews of the eclipsed sun now on the screen are from 

 drawings taken in 1851. We can get from them little idea of the 

 beauty of that brilliant clear halo of white light surrounding the 

 dark edge of the moon which observers of eclipses are pri^dleged 



