CHAPTER LXIX 



THE SUBTERRANEAN FURNACE 



" T K)T us get back to our subject. At the bottom of 

 I A mines, I told you, a high temperature prevails, 

 which keeps up during the whole year. There is 

 always the same heat, winter and summer. The 

 deepest excavation miners have ever made is in 

 Bohemia. It is inaccessible to-day. Landslides 

 have partly filled it. At the depth of 1151 meters 

 the thermometer indicated a perpetual heat of forty 

 degrees, almost the temperature of the hottest 

 regions in the world. And that, mind you, in winter 

 as well as summer. When mountainous Bohemia 

 was covered with ice and snow, it was only neces- 

 sary to go down to the bottom of the mine to pass 

 from the rigors of winter to the insupportable heat 

 of a Senegal summer. One shivered with cold at 

 the entrance and stifled with heat at the bottom. 



"The same conditions, without exception, prevail 

 everywhere. The deeper one descends in the earth, 

 the hotter one finds the temperature. In deep mines 

 the heat is such that the most unobservant workman 

 is struck by it and wonders if he is not near some 

 immense furnace." 



"The interior of the earth is then, really a stove!" 

 queried Jules. 



"Much more than a stove, as you will see. The 



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