44 ORGANISM AND ENVIRONMENT 



assistant Coxwell in a famous ascent from Wolver- 

 hampton in 1862. The balloon gradually reached a 

 height of 26,000 feet, at which the oxygen pressure in 

 the air was reduced to two fifths of the normal. 

 Glaisher then first noticed that he could not read his 

 instruments properly. Shortly afterwards his legs 

 were paralysed, and then his arms, though he could 

 still move his head. Then his sight failed entirely, and 

 afterwards his hearing, and he became unconscious. 

 Coxwell meanwhile endeavoured to pull the rope of 

 the valve, but found that not only his legs, but also 

 his arms were paralysed. He succeeded, however, in 

 seizing the rope with his teeth, thus opening the 

 valve. As the balloon descended Glaisher, about seven 

 minutes after he lost consciousness, began to hear 

 Coxwell's voice again, and then to see him, after which 

 he quickly recovered. The balloon had probably 

 reached a height of about 30,000 feet. 



In another famous high ascent from Paris the three 

 observers, Tissandier, Sivel and Croce-Spinelli, were 

 provided under Paul Bert's direction with bags of 

 oxygen to breathe from if they felt any ill effects. 

 Though the oxygen would have saved them they were 

 all paralysed before they realised their danger; and 

 only Tissandier survived. The balloon, as shown by 

 a self-registering barometer, had reached a barometric 

 pressure of 263 millimetres, corresponding to a height 

 of 30,000 feet, so that the pressure was reduced to 

 nearly a third of the normal. 



The insidious effects of want of oxygen are per- 

 haps still more strikingly illustrated in the case of 



