154 THE LAST CRUISE OF THE MIRANDA. 



dust to the depth of a mile or more, shutting out all distant 

 objects on the bottom. It was a hazy ocean with ill-defined 

 surface and shores, shading into the mountains that rose 

 above it on either side. The surface passed insensibly into 

 that finer and clearer dust which extended into the upper 

 regions of the atmosphere. At sunrise the shadow of the 

 conical peak was visible, and the sun shining on the motes 

 made the air visible on either side of the shadow, which was 

 wonderfully distinct against the clear sky. It was of deep 

 cobalt-blue, sharply contrasting with the light azure-blue of 

 the sunlit air about it. By optical illusion this shadow 

 seemed far higher than the peak itself. Owing to the curva- 

 ture of the earth, it stood far above the mountain ranges on 

 the distant horizon, a gigantic spectral peak projected against 

 the western sky, sinking as the sun mounted higher, an 

 object of indescribable grandeur. 



Travellers have often described similar shadows of other 

 peaks. Other optical phenomena occur, some due to the 

 dust alone, others due to the partially condensed moisture on 

 the dust. The Spectre of the Brocken, in Germany, and the 

 glory about Adam's Peak, in Ceylon, are well-known ex- 

 amples. 



The exquisite blue of the tropical skies, the dark blue- 

 violet sky seen from very high peaks, the various phases of 

 haze over landscapes, the charm of our Indian summer atmos- 

 phere, the green sun seen in India and in Ecuador after vol- 

 canic eruptions, the bloody sun of some climes and the 

 copper sun of others, are among the optical phenomena due to 

 atmospheric dust. 



Our trip to Greenland was from the familiar atmospheric 

 conditions of our own clime to those entirely new to me, and 

 therefore had an especial interest. The ice and snow were 

 not new except as to quantity and thickness. Much of the 

 vegetation had a sort of familiar look ; I had met so many 



