MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 13 



may bring it on. The application of suitable lotions will cure the 

 actual blindness in a day or so, but the eyes remain tender and weak 

 for long periods after a bad attack, for weeks or even months. It is 

 necessary to wear tinted spectacles if one wishes to avoid this painful 

 and troublesome experience. This is an inconvenience connected with 

 life at high altitudes which cannot be avoided except by special pre- 

 cautions. 



7. Mountain- Sickness. — Considerations on the so-called " mountain- 

 sickness " will be found in various places throughout this paper, in 

 connection with narratives of residence or adventure at high stations 

 (see the sections on Whymper's travels in the Andes, the Harvard 

 College stations in South America, Mont Blanc, etc.). 



It may be noted here that some two-thirds of the tourists who come 

 (by train in 1| hours) from the level of Manitou (6563 feet) to the 

 summit station of Pike's Peak (1-1,115 feet) are affected by the altitude, 

 though they have made no physical exertion whatever. 



Some of the cases are serious. Certain persons are not able to remain 

 on the summit at all. 



Mountain- Sickness on the Jungfrau. — The following item was found 

 in California papers early in 1895 : 



The proposed railway to the top of the Jungfrau, which is 13,671 feet high, 

 has made it desirable to determine the effect upon employees and passengers of 

 travel to so elevated a station. M. H. Kronecker, who has conducted the inves- 

 tigation, concludes that mountain-sickness sets in at altitudes varying with dif- 

 ferent persons. Beyond 10,000 feet it attacks all persons on the slightest muscular 

 exertion, but children and very old people are much less subject to it than others. 

 It varies with the character of the mountains, being usually less serious on iso- 

 lated peaks. Persons in good health can stand passive transport to the height of 

 the Jungfrau without inconvenience, but they should not remain more than two 

 or three hours, as a prolonged stay might prove disastrous. Workmen should be 

 carefully selected, and, if possible, acclimatized or frequently changed between 

 stations ; and the summit station should be so arranged that full benefit of tlie 

 view may be had without effort. 



If these statements are coiTCct, it would seem that the change of 

 barometric pressure, rather than the absolute pressure, is the immediate 

 cause of mountain-sickness. In Switzerland, persons going from a low 

 level, Interlachen, 1900 feet, up to 10,000 feet are said to be affected. 

 It is rarely felt in the Rocky Mountains under 14,000 feet ; but here 

 the traveller has previously been living at an altitude of say 6000 feet. 

 In the Andes, where the mountains often rise from high plains, the 

 sickness seems to be first felt at about 16,000 feet, say 8000 feet above 

 the lower stations. 



