229 



of the ground several seconds before each partial 

 eruption takes place. We observed this pheno- 

 menon at Vesuvius in 1805, while the mountain 

 threw out scoriae at a white heat ; we were wit- 

 nesses of it in 1802, on the brink of the immense 

 crater of Pichincha, from which nevertheless at 

 that time clouds of sulphureous acid vapours 

 only issued. 



Every thing in earthquakes seems to indicate 

 the action of elastic fluids seeking an outlet to 

 spread themselves in the atmosphere. Often, on 

 the coasts of the South Sea, the action is almost 

 instantaneously communicated from Chili to the 

 gulf of Guayaquil, a distance of six hundred 

 leagues ; and, what is very remarkable, the 

 shocks appear to be so much the stronger, as 

 the country is more distant from burning volca- 

 noes. The granitic mountains of Calabria, co- 

 vered with very recent breccia, the calcareous 

 chain of the Apennines, the country of Pignerol, 

 the coasts of Portugal and Greece, those of Peru 

 and Terra Firma, afford striking proofs of this 

 assertion *. The Globe, it may be said, is agi- 

 tated with greater force, in proportion as the 

 surface has a smaller number of funnels com- 

 municating with the caverns of the interior. At 

 Naples and at Messina, at the foot of Cotopaxi 

 and of Tunguragua, earthquakes are dreaded 



* Fieuriau dc Bellevu^ Journ. de Phys., t. lxii, p. 261 . 



