Qn Earthquakes — their causes and eff'ects; fill 



And Newton, in no less unequivocal language, says, 

 "We may learn that sulphureous steams abound in the 

 bowels of the earth, and ferment with minerals, and some- 

 times take tire, with a sudden corruscation and explosion ; 

 and if pent up in subterraneous caverns, burst the caverns 

 with a great shaking of the earth, as in the springing of a 

 mine." — Ntxotori's Optics, p. 353. 



The existence of those extensive cavities satisfactorily 

 accounts to us for the fact of earthquakes being severely felt 

 at great distances from volcanoes ; such was the case in 

 1811 and 1812, when the shores of the Mississippi, near 

 New Madrid, were literally torn to pieces, the vibration 

 being felt in many parts of the United Slates. I was at that 

 time driven from my bed in Pittsburgh by the alarming mo- 

 tion. If we look round for the cause of this in a volcano 

 we find the nearest one to New Madrid to be about one 

 thousand miles distant, there being but five in North 

 America — Orizaba, Popocatepetl, and three minor ones, all 

 in Mexico. In 1755, when Lisbon was destroyed, the 

 motion was felt over an area of four millions of square miles. 

 It extended to Spain, France, Africa, the Azores, West 

 Indies, &c., and persons on board ships forty leagues off 

 St. Vincent were thrown from their feet. In IGOI an 

 earthquake was felt in Asia, Thrace, Hungary, Bohemia, 

 Germany, Italy, and France. To account satisfactorily for 

 such extensive effects, we must admit of deep-seated chan- 

 nels of communication stretching from one portion of the 

 globe to the other, through which the explosive gases pass 

 with an instantaneous motion, accompanied by a rumbling or 

 terrible noise, peculiar to earthquakes. That these chan- 

 nels have communication with the sea, there is no disputing 5 

 for volcanoes frequently throw up salt water and fish from 

 the ocean ; this has been the case with Vesuvius and I be- 

 lieve with some of the Cordilleras. It has been observed 

 that previous to an eruption of Vesuvius, the sea retires 

 from the shores until the mountain bursts, when it returns 

 to overflow its usual boundaries. iEtna has thrown out 

 boiling water with sea-shells, (1755,) and during the great 

 earthquakes of Peru, in which Riobamba, Quero, Sec, were 

 destroyed, with sixteen thousand persons, fetid water issued 

 and filled up the valleys one thousand feet deep and six 

 hundred broad. The source of this water could be no other 

 than the ocean. It should here be recollected that all the 



