402 VOLTAIC ACTION, AND 



the plates of a common battery.* That volcanos 

 are in some way abundantly supplied with sea 

 water, is evident from the vast quantities of 

 steam discharged during their eruptions, which 

 contains chloride of sodium, hydro-chloric acid, 

 chloride of copper, iron, &c. as well as from their 

 geographical positions near the sea. In short, the 

 earth may be regarded as a huge galvanic pile, 

 kept in a state of perpetual subterranean che- 

 mical action by the waters of the ocean, as our 

 little batteries are maintained in action by vari- 

 ous solutions. 



When the plates of a common battery are 

 completely oxidized, chemical action ceases : 

 so when all the materials within a given range 

 of subterranean territory become saturated with 

 oxygen, sulphur, chlorine, &c. chemical action 

 ceases, and the volcanic forces become quiescent, 

 to be renewed elsewhere for indefinite periods of 

 time, until exhausted or burnt out like the plates 

 of a voltaic battery. 



In North America, they have been nearly 



* The hydrogen of water may unite with sulphur, making sul- 

 phuretted hydrogen ; while the union of oxygen with sulphur, 

 makes sulphurous acid, which combines with lime, and drives 

 off carbonic acid, a common product of hot springs and vol- 

 canos. The nitrogen of atmospheric air which is admitted 

 through craters, and is mixed in greater or less quantity with 

 all water, combines with hydrogen, forming ammonia. In fine, 

 there is no limit to the play of affinities that take place in this 

 grand laboratory, under the agency of so intense a heat. 



