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celona, the beds of native sulphur at Carupano, 

 and the emanations of sulphurous acid, which 

 are perceived at times in the savannahs. It 

 cannot be doubted also, that the decomposition 

 of water by the pyrites at an elevated tempera- 

 ture, favoured by the affinity of oxidated iron 

 for earthy substances, may have caused that 

 disengagement of hydrogen gas, to the action 

 of which several modern geologists have attri- 

 buted so much importance. But in general, 

 sulphurous acid is perceived more commonly in 

 the eruption of volcanoes, than hydrogen is; 

 and it is principally the odour of this acid, that 

 prevails while the earth is agitated by violent 

 shocks. When we take a general view of the 

 phenomena of volcanoes and earthquakes, when 

 we recollect the enormous distance at which 

 the commotion is propagated below the basin 

 of the sea, we readily lay aside explanations, 

 that are founded on small strata of pyrites and 

 bituminous marls. I am of opinion, that the 

 shocks so frequently felt in the province of Cu- 

 mana are as little to be attributed to the rocks 

 above the surface of the earth, as those which 

 agitate the Apennines are to asphaltic veins, or 

 springs of burning petroleum. The whole of 

 these phenomena depend on more general, I 

 would almost say, on deeper causes ; and it is 

 not in the secondary strata, which form the ex- 

 terior crust of our globe, but in the primitive 



