656 THE POPULAR SCIENCE MONTHLY. 



fell in almost too well with our anticipations that the air is an even 

 more elaborate trap to catch the sunbeams than had been surmised, 

 and that this effect of selective absorption and radiation was inti- 

 mately connected with that change of the primal energies and primal 

 color of the sun which we had climbed toward it to study. 



On the fourth day, after break-neck ascents and descents, we finally 

 ascended by a ravine, down which leaped a cataract, till, at nightfall, 

 we reached our upper camp, which was pitched by a little lake, one of 

 the sources of the waterfall, at a height of about twelve thousand 

 feet, but where we seemed in the bottom of a valley, nearly surrounded 

 as we were by an amphitheatre of rocky walls which rose perpen- 

 dicularly to the height of Gibraltar from the sea, and cut off all view 

 of the desert below or even of the peak above us. 



The air was wonderfully clear, so that the sun set in a yellow 

 rather than an orange sky, which was reflected in the little ice-rimmed 

 lakes and from occasional snow-fields on the distant waste of lonely 

 mountain-summits on the west. 



The mule-train sent off before by another route had not arrived 

 when we got to the mountain-camp, and we realized that we were far 

 from the appliances of civilization by our inability to learn about our 

 chief apparatus, for here, without post or telegraph, we were as com- 

 pletely cut off from all knowledge of what might be going on with it 

 in the next mountain ravine as a ship at sea is of the fate of a vessel 

 that sailed before from the same port. During the enforced idleness we 

 ascended the peak nearly three thousand feet above us, with our lighter 

 apparatus, leaving the question of the ultimate use of the heavy ones 

 to be settled later. There seemed little prospect of carrying it up, 

 as we climbed where the granite walls had been split by the earth- 

 quakes, letting a stream of great rocks, like a stone river, flow down 

 through the interstices by which we ascended, and, in fact, the heav- 

 ier apparatus was not carried above the mountain-camp. 



The view from the very summit was over numberless peaks on the 

 west to an horizon fifty miles away, of unknown mountain-tops, for, 

 with the exception of the vast ridge of Mount Tyndall, and one or 

 two less conspicuous ones, these summits are not known to fame, and, 

 wonderful as the view may be, all the charm of association with human 

 interest which we find in the mountain landscape of older lands is 

 here lacking. 



It was impossible not to be impressed with the savage solitude of 

 this desert of the upper air, and our remoteness from man and his 

 works, but I turned to the study of the special things connected with 

 my mission. Down far below the air seemed filled with reddish dust 

 that looked like an ocean. This dust is really present everywhere (I 

 have found it in the clear air of Etna), and, though we do not realize 

 its presence in looking up through it, to one who looks down on it the 

 dwellers on the earth seem indeed like creatures at the bottom of a 



