1895.] on Influence of Science on Mountaineering. 457 



early part of this century, the effect of the rarefied air is almost 

 uniformly mentioned. Often, it may be suspected, this was because 

 the writer thought it proper to allude to the subject rather than 

 because he really suffered from mountain sickness. Within the last 

 few years the expedition has several times been made from Chamonix 

 to the top of Mont Blanc and back to Chamonix within twenty-four 

 hours ; once I believe in about eighteen hours. The vertical height 

 to be ascended is over 12,000 feet. In the ascent of Elbruz (Caucasus) 

 one party experienced no discomfort at all, another party was 

 affected. Of the more recent experiences in the Andes and Karakoram 

 I need hardly remind you. Perhaps the Karakoram expedition shows 

 the greatest height reached, though not much above the Schlagintweit 

 expedition. A very curious point is brought out by the chart, viz. 

 that heights far exceeding Mont Blanc had been reached long before 

 the ascent of that mountain drew attention to the question. Thus 

 the Karakoram Pass, about the height of Elbruz, has been known for 

 centuries as a well established trade route, and another pass (the 

 Changlung) of over 19,000 feet has long been known. Indeed, 

 Western people were still speculating on the possibility of ascending 

 to any higher elevation than that of Mont Blanc, while centuries 

 before in the East men had reached points nearly 4000 feet higher. 

 Assuming that the highest point of the earth's crust is about 30,000 

 feet, this other diagram shows in another form how much has been 

 accomplished by mountaineers, and, it may be added, how little 

 apparently remains to be done. The question of the ascent of the 

 highest point indicated (Kabru) on the diagram is doubted by many 

 good authorities. There is no doubt about the height of the moun- 

 tain which has been triangulated, but the question is whether the 

 travellers did not mistake the peak they actually ascended. Whether 

 the party actually did so or not, seeing that there is conflict of opinion, 

 must remain uncertain. But the Karakoram experience, the latest, 

 tends to show that it was certainly not physically impossible. 



Experiments in the laboratory have been conducted with apparatus 

 on a large scale similar to that wbich I show you here in miniature. 

 By means of this apparatus the atmospheric pressure can be reduced to 

 any degree required, and the pressure can be, by an ingenious con- 

 trivance, maintained absolutely constant for any desired length of 

 time. 



This apparatus has been devised for other purposes, but essentially 

 it could serve like M. Bert's "pneumatic cabinet." You may jud^e, 

 and judge rightly, that the conditions produced in a man who shuts 

 himself up for a time in such an apparatus and lowers the pressure 

 are different from those on the mountaineer. At least M. Bert's 

 pneumatic cabinet has proved the existence of other factors in the 

 problem. M. Paul Bert, experimenting on himself, sustained a 

 diminished pressure equal to 32,528 feet for a short time — a lower 

 pressure than that of Mount Everest. From many experiments he 

 was led to the conclusion that deficiency of oxygen was the main cause 



