GEOLOGY. 637 



and have met with devoted men, who years after have 

 preserved the memory of my ascents. 



When we have arrived at a moderate height, the ascent 

 of any mountain becomes a heavy toil. Movement and 

 respiration become extremely difhcult in proportion as we 

 rise. There even comes a time when, as De Saussure re- 

 marks, one is obliged to stop every fifty yards overwhelmed 

 by an inexplicable fatigue. Then the rarefaction of the 

 air renders the oppression greater and greater, and the 

 heart beats as if it would burst from the chest, and the 

 traveller feels every instant as if he would faint. Twice, 

 Baron Mliller, abandoned by his guides and companions, 

 fainted quite away on the borders of the crater of Orizaba, 

 whilst torrents of blood gushed from his chest. 



After long journeys in the snow the traveller, subdued 

 by cold and lassitude, experiences an insurmountable de- 

 sire to sleep, and yet dare not, for all the world contains, 

 yield himself up to it, for this sleep conducts him to in- 

 evitable death — a fact known to all travellers. 



On the frozen shoi^es of Tierra del Fuego, Solander, lost 

 in the mountains, said imperiously to his companions in 

 misfortune, " Whoever sits down will sleep, and he who 

 sleeps will never wake again." Yet so overpowering, so 

 unconquerable is this tendency to sleep, that several of the 

 men yielded to it, and Solander himself, a few moments 

 afterwards, sank down upon the snow, where his friend, 

 the illustrious Sir Joseph Banks, had all the difficulty in 

 the world to arouse him. 



But when we have arrived at the summit of a mountain, 

 the splendour of the sight makes one quite forget the 

 fatigue of the ascent. This I experienced lately when I 

 had reached the borders of Etna's crater. 



There upon this throne, round which the lightning plays. 



