232 Historical 



pass, "the action of the atmosphere is diminished one quarter or 

 5500 pounds, which expands the vessels in a similar proportion". 

 Then, to the explanations "furnished by science" Rey adds one, 

 which I cannot help finding rather queer: 



We can hardly climb to the top of a very lofty tower without 

 making frequent pauses on the way, and usually we reach the top only 

 with great effort. Certainly that is not because of the rarefaction of 

 the air, nor even because of weariness. Is it not because we have had 

 to lift our legs many times consecutively, by a law quite different 

 from that of walking and much harder to obey? In fact, all the 

 muscles of our organs of locomotion, set to work at the same time by 

 an ascensional movement to the continuity of which they are not 

 accustomed, experience from it a fatigue which forces us to pause 

 frequently, which increases as long as we continue ,t° mount, but 

 which ceases as soon as we have reached the top and does not return 

 while we are taking the same way downward. Well, that which takes 

 place in a man climbing a stairway he experiences with greater reason 

 on the side of a rugged mountain, because here there is a combination 

 of a long walk on trails often requiring violent and unaccustomed use 

 of muscular powers and a great rarefaction of the atmospheric air. 

 If we could wind around Mont Blanc and reach its crest by a gradual 

 slope as we wind around the Saint Gothard or the Simplon pass, it 

 would no longer be necessary to make the unnatural movement of 

 the legs, members which become heavier to raise in proportion to the 

 contraction of the column of the air, and consequently we should no 

 longer feel this distress which we mistake for fatigue. (P. 335.) 



Tschudi, 61 the celebrated. German traveller whose complete de- 

 scription of the mountain sickness in the Cordillera of the Andes 

 we have already quoted, explains the extreme weariness of the 

 lower limbs which one experiences in ascending, like von Hum- 

 boldt and the Weber brothers: 



Since the head of the femur, according to the researches of Weber, 

 is held in its cavity by atmospheric pressure, when this pressure di- 

 minishes, a continuous muscular contraction must replace it. (Vol. II, 

 p. 66.) 



He then reports, but without seeming to believe it, the explana- 

 tion given by the Indians about metallic emanations: 



There are places where it is known that the Veta is more severe 

 than elsewhere, and they are sometimes lower than others where it 

 is much less evident, so that it does not seem to be caused entirely by 

 the rarefied air, but also by some unknown climatic influence. Usually 

 these places are rich in minerals, whence comes the general belief of 

 the Peruvians that these effects are due to metallic emanations. 



Dr. Archibald Smith G2 does not consider these differences; but 



