THE GEYSER. 219 



phureous smell accompanying thunder, just as there 

 is accompanying earthquakes, which shows that 

 there are other atmospheric ingredients acted on by 

 the commotion of the water and the heat. 



When water remains on the ground in the liquid 

 state, its operations are more open to unguided ob- 

 servation than when it is on its aerial passage from 

 the sea to the land ; and its natural uses there are 

 much more profitably viewed in connexion with 

 those substances and productions to which it is use- 

 ful. But on the earth's surface, and even in cavities 

 within the earth, heat has the same kind of effect 

 upon it as when it is in the atmosphere. Boiling 

 springs are among the most curious of these phe- 

 nomena; and one of the most remarkable is the 

 great Geyser in Iceland, which is a sort of natural 

 steam engine, which, like some of the high-pressure 

 engines, blows its steam into the air. 



THE GEYSER. 



Great part of Iceland is volcanic, and there is no 

 doubt that there are many curious caverns that have 

 been formed below ground, as there are in all volcanic 

 countries. The Geyser appears to have a boiler, 



