1817.] to the Summit of Mount Blanc. 101 
at all times is covered with snow. Here the thinness of the atmos- 
phere began to affect my head with a dull and heavy pain. I also 
found, to my great surprise, an acute sensation of pain, very diffe- 
rent from that of weariness, immediately above my knees. Having 
finished our repast, we pursued our journey, and soon arrived at a 
chasm which could not have existed many days, for it was not 
formed at the time of M. de Saussure’s ascent. Misled by this last 
circumstance, for we concluded that, as he had seen no rents what- 
ever from the time that he passed the place where he slept the 
second night, none were likely to be formed, we had left our ladder 
about a league behind; but as the chasm was far from wide, we 
passed it on the poles that we used for walking; an expedient which 
suggested to me that the length of our ladder might be easily in- 
creased by the addition of several poles laid parallel and fastened to 
its end; and that the hazard of finding our retreat cut off from the 
enlargement of the chasms might by this means be materially 
diminished. At this place I had an opportunity of measuring the 
height of the snow which had fallen during the preceding winter, 
and which was distinguished by its superior whiteness from that of 
the former year. I found it to be five feet. The snow of each 
particular year appeared as a separate stratum ; that which was more 
than a twelvemonth old was perfect ice; while that of the last 
winter was fast approaching to a similar state. At length, after a 
difficult ascent, which lay among precipices, and during which we 
were often obliged to employ the hatchet in making a footing for 
our feet, we reached and reposed ourselves upon a narrow flat which 
is the last of three from the foot of the small mountain, and which, 
according to M. de Saussure, is but 150 fathoms below the level of 
thesummit. Upon this platform 1 found a beautiful dead butterfly, 
the only appearance which, from the time I entered on the snow, I 
had seen of any animal. The pernicious effects of the thinness of 
the air were now evident on us all; a desire, almost irresistible, of 
sleep came on. My spirits had left me; sometimes indifferent as 
to the event, I wished to lie down; at others, I blamed myself for 
the expedition; and, though just at the summit, had thoughts of 
turning back, without accomplishing my purpose. Of my guides 
many were in a worse situation ; for, exhausted by excessive vomit- 
ing, they seemed to have lost all strength, both of mind and body. 
But shame at length came to our relief, I drank the last pint of 
water that was left, and found myself amazingly refreshed. Yet the 
pain in my knees had increased so much, that at the end of every 20 
or 30 paces I was obliged to rest till its sharpness was abated. My 
lungs with difficulty performed their office, and my heart was 
affected with violent palpitation, At last, however, but witha sort 
of apathy which scarcely admitted the sense of joy, we reached the 
summit of the mountain; when six of my guides, and with them 
my servant, threw themselves on their faces, and where imme- 
diately asleep. I envied them their repose; but my anxiety to 
obtain a good observation for the latitude subdued my wishes for 
