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. Von 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 voleanos. 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. 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, aud 
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 Fleuriau de Bellevue, Journ. de Physique, t. Ixii, p. 261. 
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