THE EARTH. 133 



Few of our -great mountains have been esti- 

 mated in this manner, travellers having perhaps 

 been deterred by a supposed impossibility of 

 breathing at the top. However, it has been in- 

 variably found, that the air in the highest that 

 our modern travellers have ascended, is not at all 

 too fine for respiration. At the top of the Peak 

 of Teneriffe, there was found no other inconveni- 

 ence from the air except its coldness : at the top 

 of the Andes there was no difficulty of breathing 

 perceived. The accounts, therefore, of those who 

 have asserted that they were unable to breathe, 

 although at much less heights, are greatly to be 

 suspected. In fact, it is very natural for man- 

 kind to paint those obstacles as insurmountable, 

 which they themselves have not had the fortitude 

 or perseverance to surmount. 



The difficulty and danger of ascending to the 

 tops of mountains, proceeds from other causes, 

 not the thinness of the air. For instance, some 

 of the summits of the Alps have never yet been 

 visited by man ; but the reason is, that they rise 

 with such a rugged and precipitate ascent, that 

 they are utterly inaccessible. In some places 

 they appear like a great wall of six or seven hun- 

 dred feet high ; in others, there stick out enor- 

 mous rocks, that hang upon the brow of the steep, 

 and every moment threaten destruction to the 

 traveller below. 



In this manner almost all the tops of the 

 highest mountains are bare and pointed: And 

 this naturally proceeds from their being so con- 

 tinually assaulted by thunders and tempests. All 



