A WHEWELLITE ESSAY ON MARS. 145 



guides would appear to have become more inured to the 

 hardships of high places than they were in 1787. We 

 learn that 'at 13,000 feet, upon the Petit-Plateau, 

 where he passed the night, the hardy guides, to whom 

 the previous marching was absolute child's play, had 

 only removed five or six spades-full of snow in order to 

 pitch the tent, when they were obliged to give in and 

 take a rest, while several felt so indisposed that they 

 were compelled to lie upon the snow to prevent them- 

 selves from fainting. The next day,' says De Saussure, 

 ' in mounting the last ridge which leads to the summit, 

 I was obliged to halt for breath at every fifteen or six- 

 teen paces, generally remaining upright and leaning on 

 my stock ; but on more than one occasion I had to lie 

 down, as I felt an absolute need of repose. If I attempted 

 to surmount the feeling, my legs refused to perform 

 their functions ; I had an initiatory feeling of faintness, 

 and was dazzled in a way quite independent of the 

 action of the light, for the double crape over my face 

 entirely sheltered the eyes. As I saw with regret the 

 time intended for experiments on the summit slipping 

 away, I made several attempts to shorten these in- 

 tervals of rest. I tried, for instance, a momentary 

 stoppage every four or five paces, instead of going to 

 the limit of my strength ; but to no purpose, as at the 

 end of the fifteen or sixteen paces I was obliged to rest 

 again for as long a time as if I had done them at a 

 stretch. . . . The only thing which refreshed me and 

 augmented my strength was the fresh wind from the 

 north. When, in mounting, I had this in my face, and 



L 



