GEOLOGY. CGI 



the Cyclops, in recognition of the singuUxr changes to 

 which it is liable in the course of existence. 



These eruptions containing fish are not rare. Hum- 

 boldt relates that in one of them, Cotopaxi ejected such a 

 quantity of Pimelodes on the estate of the Marquis of 

 Selvalegre, that they poisoned the air all round. Towards 

 the close of the last century the town of Iburra was ravaged 

 by a malignant fever, which was attributed to the mias- 

 mata arising from an enormous mass of these fishes vomited 

 by a neighbouring volcano. 



Astonished at the power and variety of volcanic phe- 

 nomena, the learned of all ages have sought to explain the 

 mystery of them. Numerous hypotheses have been put 

 forward for this purpose, and have successively fallen into 

 oblivion. We shall mention only some of the most cele- 

 brated. 



During the era of the encyclopedists, in the eighteenth 

 century, when all kinds of audacious theories were put 

 forward, volcanoes Avere explained very variously. One of 

 the ideas then most in vogue was that they only resulted 

 from the ignition of a mass of coal and pyrites which 

 happened to be in the strata of the mountain in question. 



Lemery the chemist proposed another hypothesis. In 

 his experiments in the laboratory he had j^roduced a sort 

 of small artificial volcano ])y mixing together finely 

 powdered sulphur, iron-filings, and a little water. In a 

 short space of time such an amount of chemical action 

 was set up in this mixture that it took fire. According to 

 the professor of the Jardin du Roi, similar phenomena take 

 place in burning mountains. All those who saw this 

 experiment went forth convinced. BuflFon himself adopted 

 this hypothesis. "Behold," said this great man, "what a 

 volcano is in the eyes of a master of physics!" 



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