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ideas, and comprehend in one point of view every 

 thing that relates to these phenomena, so terri- 

 fic, and so difficult to explain. If it be the duty 

 of those natural philosophers, who visit the 

 Alps of Switzerland, or the coasts of Lapland, 

 to extend our knowledge respecting the glaciers 

 and the aurora borealis, it may be expected, that 

 a traveller, who has traversed Spanish America, 

 should have chiefly fixed his attention on volca- 

 noes and earthquakes. Each part of the Globe 

 is an object of particular study ; and when we 

 cannot hope to penetrate the causes of natural 

 phenomena, we ought at least to endeavour to 

 discover their laws, and distinguish, by compa- 

 rison of numerous facts, what is constant and 

 uniform from what is variable and accidental. 



The great earthquakes, which interrupt the 

 long series of slight shocks, appear to have no 

 regular periods at Cumana. They have taken 

 place at intervals of fourscore, a hundred, and 

 sometimes less than thirty years ; while on the 

 coasts of Peru, for instance at Lima, a certain 

 regularity is observed in the periods of the total 

 ruin of the city. The belief of the inhabitants 

 in the existence of this uniformity has a happy 

 influence on public tranquillity, and the encou- 

 ragement of industry. It is generally admitted, 

 that it requires a sufficiently long space of time 

 for the same causes to act with the same energy; 

 but this reasoning is just only in as much as the 



