42 Natural History of Volcanos and Earthquakes. 



place, I have also shown, that the seat of volcanic action may be 

 looked for at depths far less than Stukeley supposes. But there 

 is no reason to believe that earthquakes could go on at greater 

 depths than volcanic actions. Supposing that the interior of the 

 earth is still fluid, and that rents conducting water, extend from 

 the surface to the fluid nucleus, it is easy to conceive that the ac- 

 tions of the steam may be felt at very remote distances. 



We have already pointed out the close connection which ex- 

 ists between earthquakes and volcanic eruptions. Yon Hum- 

 boldt, in his travels near the Equator, gives several examples of 

 this. It may not be superfluous to refer here to what this illus- 

 trious philosopher asserts generally with regard to these phenom- 

 ena, at the end of the 4th chapter of the 2d volume of Part I, 

 Book 2.* 



Every thing seems to show that earthquakes are caused by 

 the effort of elastic fluids seeking an outlet. On the coasts of 

 the South Sea their action is often communicated almost instan- 

 taneously from Chili to the Gulf of Guayaquil, a distance of 

 600 geographical miles ; and, what is very extraordinary, the 

 shocks seem to be so much the stronger, the greater the distance 

 from the active volcanos. The granite mountains of Calabria, the 

 limestone chain of the Apennines, the county of Pignerol, the 

 coast of Portugal and Greece, Peru, and the continent of Amer- 

 ica, furnish striking proofs of this assertion.f It might be sup- 

 posed that the earth would be more violently shaken, the fewer 

 the openings on the surface which communicate with the inte- 

 rior. At Naples and at Messina, at the foot of Cotopaxi, and 

 the Tunguragua, earthquakes are dreaded only when vapors 

 and flames do not issue from the mouth of the volcano. In the 

 kingdom of Quito, the great catastrophe of Riobamba led many 

 well informed persons to believe that this unfortunate country 

 would be less often disturbed if the subterranean fire would 

 succeed in destroying the dome of porphyry of Chimborazo, and 

 if this colossal mountain should become an active volcano. 

 At all times, analogous facts have given rise to similar hypoth- 

 eses. The ancient Greeks, who, like us, attributed earthquakes 



* See also what Von Buch says on Vesuvius. Geognostische Beobacht. vol. ii, 

 p. 129. 



t rieuriau deBellejue, Jouin. de Physique, t. lxii,p. 261. 



