178 HEAT OF THE WATERS : CLIMATE, 



French expedition, we are told that the thermo- 

 meter rose once to 52°'5 C. (126°'5 I\) ; and at 

 Murzouk (in Fezzan) Lyon says that lie saw 

 it at 56°-2 C. (133°-16 P.) Certain it is that the 

 variations of temperature occurring on the earth 

 extend over 100° C. (180° I\) 



It is indeed remarkable, that the human body is 

 not only able to bear exposure to these changes, 

 but can even become accustomed to them. More- 

 over, the experience of many travellers agrees in 

 this, that an unusually severe cold in still air is 

 more easily endured than an unusually high heat. 

 It is clear that man has readier means of sheltering 

 himself from the former than from the latter ; be- 

 sides this, extreme degrees of cold are very seldom 

 attended with much motion in the air. Cold winds, 

 however, as you probably know from experience, 

 are more distressing, than mere exposure to very far 

 lower temperature. Sir John Eoss and his sailors 

 moved about, and worked, without much inconve- 

 nience in the open air, under cold which froze 

 mercury, although they found the effect of a strong 

 wind, only a few degrees below the freezing point 

 of water, quite insupportable. 



Darwin mentions several instances of travellers 

 having been frozen by violent storms in the moun- 

 tain passes of Northern Chili, when the thermo- 

 meter stood but little below the freezing point, and 

 snow was not falling. 



