SUNLIGHT AND THE EARTH'S ATMOSPHERE. 653 



fire and shelter, and above all we must have dry air to get clear 

 skies. First I thought of the Peak of Teneriffe, but afterward some 

 point in the Territories of the United States seemed preferable, par- 

 ticularly as the Government offered to give the expedition, through 

 the Signal Service, and under the direction of its head, General Hazen, 

 material help in transportation and a military escort, if needed, any- 

 where in its own dominions. No summit in the eastern part of the 

 United States rises much over seven thousand feet ; and, though the 

 great Rocky Mountains reach double this, their tops are the home of 

 fog and mist, so that the desired conditions, if met at all, could only 

 be found on the other side of the continent in Southern California, 

 where the summits of the Sierra Nevadas rise precipitously out of the 

 dry air of the great wastes in lonely peaks, which look eastward down 

 from a height of nearly fifteen thousand feet upon the desert lands. 



This remote region was, at the time I speak of, almost unexplored, 

 and its highest peak, Mount Whitney, had been but once or twice 

 ascended, but was represented to be all we desired could we once climb 

 it. As there was great doubt whether our apparatus, weighing sev- 

 eral thousand pounds, could possibly be taken to the top, and we had 

 to travel three thousand miles even to get where the chief difficulties 

 would begin and make a desert journey of one hundred and fifty miles 

 after leaving the cars, it may be asked why we committed ourselves 

 to such an immense journey to face such unknown risks of failure. 

 The answer must be that mountains of easy ascent and fifteen thousand 

 feet high are not to be found at our doors, and that these risks were 

 involved in the nature of our novel experiment, so that we started out 

 from no love of mere adventure, but from necessity, much into the 

 unknown. The liberality of a citizen of Pittsburg, to whose encour- 

 agement the enterprise was due, had furnished the costly and delicate 

 apparatus for the expedition, and that of the transcontinental rail- 

 roads enabled us to take this precious freight along in a private 

 car, which carried a kitchen, a steward, a cook, and an ample larder 

 besides. 



In this we crossed the entire continent from ocean to ocean, stopped 

 at San Francisco for the military escort, went three hundred miles 

 south so as to get below the mountains, and then turned eastward again 

 on to the desert, with the Sierras to the north of us, after a journey 

 which would have been unalloyed pleasure except for the anticipation 

 of what was coming as soon as we left our car. I do not indeed know 

 that one feels the triumphs of civilization over the opposing forces of 

 Nature anywhere more than by the sharp contrasts which the marvel- 

 ous luxury of recent railroad accommodation gives to the life of the 

 desert. When one is in the center of one of the great barren regions 

 of the globe, and, after looking out from the windows of the flying 

 train on its scorched wastes for lonely leagues of habitless desolation, 

 turns to his well-furnished dinner-table, and the fruit and ices of his 



