ON ITS EXTERIOR. EARTHQUAKES. 197 



of only a few miles. Almost all the inhabitants were terrified 

 and quitted the city, in which large masses of silver were 

 stored ; but the most courageous, when they had become 

 somewhat accustomed to the subterranean thunder, returned 

 and fought with the bands of robbers who had taken pos- 

 session of the treasure. Neither at the surface, nor in 

 mines 1598 English feet in depth, could the slightest 

 trembling of the ground be perceived. In no part of the 

 whole mountainous country of Mexico had any thing similar 

 been ever known before, nor has this awful phsenomenon 

 been since repeated* Thus, as chasms in the interior of the 

 Earth close or open, the propagation of the waves of sound 

 is either arrested in its progress, or continued until it 

 reaches the ear. 



The activity of a burning mountain, however awfully 

 picturesque the spectacle which it presents to us, is 

 always limited to a very small space; whereas earth- 

 quakes, whose movements are scarcely perceptible to the 

 eye, propagate their waves sometimes to distances of 

 many thousand miles. The great earthquake which, on 

 November 1st, 1755, destroyed Lisbon, and the effects of 

 which have been well traced out by the great philosopher 

 Kant, was felt in the Alps, on the coasts of Sweden, in 

 the West India Islands '(Antigua, Barbadoes, and Mar- 

 tinique), on the great lakes of Canada, in Thuringia, 

 in the flat country of northern Germany, and in small 

 inland lakes on the shores of the Baltic. Remote foun- 

 tains were interrupted in their flow, a phenomenon of 

 earthquakes which had even been noticed among the an- 

 cients by Demetrius of Calatia. The thermal springs at 

 Toplitz dried up, and again returned, inundating every 



