Balloon Ascensions 191 



M. Glaisher states that one soon becomes accustomed to the 

 influence of rarefied air, and cites his own experience in this 

 regard. He expresses hopes on this subject that show both keen 

 imagination and scientific understanding: 



The diminution of pressure .... should act in a very special way 

 on persons who are journeying in the air for the first time. I can 

 make this statement from my own personal experience, which cer- 

 tainly has some value, for I have not always been able to ascend 

 without ill consequences to a height which ordinarily produces great 

 distress, and generally brings on discoloration of the hands and face. 

 I recall having caused great astonishment in a group of scientists by 

 stating that I was accustomed to rising to very lofty altitudes ■ without 

 turning blue. I am really convinced that I have become acclimated 

 to the effects of the rarefied air found at six kilometers from the 

 surface of the earth, and I flatter myself that I can breathe freely in 

 these strata high above sea level. I even have no doubt that this 

 acclimatization can be sufficiently developed to exercise a considerable 

 influence on the scientific use of balloons. At eight or ten kilometers I 

 have tested upon M. Coxwell and myself the limits of our ability 

 to live in rarefied air. Frequent trials would increase this height, and 

 I am certain that it could be extended even more if one used artificial 

 means to aid respiration. Certainly human lungs would find up there 

 their Columns of Hercules, but I do not hesitate to declare that these 

 impassable boundaries are still very far from the regions I have 

 reached. (Voyages aeriens, P. 9.) 



The learned meteorologist of Greenwich, in another passage of 

 his work, again refers to the future he predicts for ascents to 

 great heights; he expresses with unusual vigor his unlimited 

 confidence in the fruitful efforts of science. We shall show in the 

 rest of this work that these hopes have not been disappointed: 



As I have already explained in the introduction, I do not doubt 

 that some one will succeed in making observations in regions which 

 I could not attain without fainting. I am persuaded that a day will 

 come when aeronauts will surpass me just as I exceeded the height of 

 Barral and Bixio, who in their turn reached altitudes higher than 

 Sakaroff and Gay-Lussac. I certainly shall not take it upon myself to 

 set the limits of human activity and indicate the point, if it exists, 

 where nature says to the aeronauts: "You shall go no further." (Voy- 

 ages aeriens, p. 67.) 



For about ten years, there has been no ascent to a great height, 

 and in the scientific ascents to moderate heights, the aeronauts, 

 preoccupied with important problems of meteorology and physics, 

 neglected completely the physiological phenomena whose slight 

 modifications could not be observed without having great attention 

 devoted to them. 



