*If we don't become airtight immediately, we must pull the valve 

 and land, if we don't want to suffocate.' We didn't yet know that the 

 rope of the valve was blocked. . . . 



Both of us confident in this last resource, I went on with my work. 

 But the hole was big ! Bit by bit, however, the whistling grew feebler, 

 then was silent. Never have I appreciated silence so much. The 

 pressure already in our little home had gone down to less than two- 

 thirds of normal. Happily we had a reserve of liquid oxygen. I poured 

 some of it on the floor in small quantities^ and the oxygen rapidly 

 evaporating increased the pressure. 



We still went up. The sky became darker. 



Twenty-five past four ! Twenty-eight minutes ago we were still in 

 Augsburg, 1650 feet above sea-level. 



'What altitude, Kipfer.^' 



'51,200 feet.' 



In less than half an hour we had gone up over 9 miles. The balloon, 

 whose shape at the moment of departure was rather that of a dried 

 pear than of an apple, had now inflated following upon the expansion 

 of the gas and had become perfectly spherical. The excess gas escaped 

 by the neck and our aerostat reached its first position of equilibrium. 



At last here we are in the stratosphere ! 



Around us the sky. The beauty of this sky is the most poignant 



thing we have seen: it is sombre, dark blue or violet, almost black. 



If the air were perfectly transparent, we should see the earth over a 



radius of 280 miles, and our visual field would cover 246,000 square 



miles of the planet (more than the surface of all France). But beneath 



the stratosphere there is the troposphere, whose upper limit on that 



day was about 7^ miles : it is much less transparent. At the horizon we 



perceive the confines of the two zones, as if drawn with a ruler. If one 



looks obliquely across the troposphere, the earth, so distant, is 



invisible : there is nothing to be seen but fog. But the more the glance 



is directed downwards, the more visible is the earth. Beneath us is the 



Bavarian plain. But, even if we look vertically down, the picture is 



blurred as in a bad photograph. There is, in fact, between us and the 



earth nine-tenths of the atmosphere, almost as much as if, at sea-level, 



we were looking at the moon. Alone, the mountains emerge from the 



foggiest regions of the troposphere. At first hidden by clouds, they 



1 If one pours out too much oxygen at a time, the sudden increase of pressure 

 affects the ear. 



[10] 



