84 Historical 



level; others at twelve hundred, several at fifteen and sixteen hun- 

 dred; as for me, like most of the dwellers on the Alps, I do not begin 

 to be noticeably affected until at nineteen hundred fathoms; but 

 above this limit, the best trained men begin to suffer when they hurry 

 a little. (P. 209.) 



Finally they had to descend; from eleven o'clock to half -past 

 three, De Saussure remained on the summit, and he was sorry to 

 leave, because, he says, and I call the attention of the reader to 

 this extremely important remark: 



§2021. Although I had not wasted a single moment, in these 

 four hours and a half I could not make all the experiments which I 

 had frequently finished in less than three hours at sea level . . . But 

 I kept the well founded hope of finishing, on the col du Geant, what 

 I had not done, and what probably no one will ever do, on Mont 

 Blanc. (P. 210.) 



The descent was accomplished successfully and without great 

 fatigue: 



As the movement one makes while descending does not compress 

 the diaphragm, it does not hamper respiration, and one does not 

 suffer from the rarity of the air. 



The example of the illustrious physicist was soon followed. 

 Seven days after his famous ascent, the English colonel Beaufoy 117 

 in his turn reached the summit of the giant of the Alps. It was not 

 without keen sufferings, as the following extracts from his account 

 prove. 



Leaving Chamounix August 8, 1787, he slept with his ten guides 

 at the hut built in 1786 by the orders and at the expense of M. de 

 Saussure. The first physiological phenomenon which the colonel 

 mentions is thirst: 



Our thirst, since we had reached the upper regions of the air, 

 had become unendurable. Hardly had I drunk when my mouth was 

 dry. Although I was drinking constantly, the quantity of my urine 

 was very small; its color was very dark. The guides were similarly 

 affected; they did not wish to taste wine .... 



The rarity of the air soon began to give me a violent headache; 

 to my great surprise, I also felt a keen sensation of pain just above 

 my knees .... 



When we were within .150 fathoms (270 meters) of the summit, 

 the harmful effects of the rarity of the air was evident in all of us; 

 an almost irresistible desire to sleep possessed us. My energy had 

 left me; indifferent to everything, I thought only of lying down on the 

 ground; at other times, I regretted this expedition, and when I was 

 almost at the summit, I thought of descending, without doing it how- 

 ever. Many of my guides were in the most pitiful condition; exhausted 



