NATURAL HISTORY. 75 



portioned to its force and to the resistance it meets with. 

 And these effects will continue till it finds a vent, 

 perhaps in the sea, or tiil it has diminished its force by 

 being greatly expanded. This explanation corresponds 

 entirely with all the phenomena which are observed re- 

 specting earthquakes. They proceed with a wave-like 

 motion, and are felt at different places, not at the same 

 instant, but at different times, in proportion to the 

 distance. 



We can also confirm what has been advanced, by 

 connecting it with two other circumstances, It is well 

 known that mines exhale vapours, independent of the 

 wind produced by the current of the water; we often 

 see currents of unhealthy air and suffocating vapours'. 

 We also know that there are holes, abysses and deep 

 lakes in the earth, which produce winds, like the lake 

 Boleslaw in Bohemia, &c. 



From history we have innumerable instances of the 

 dreadful and various effects of these terrible phenomena. 

 Pliny, in his first book, chap. 84, relates, that in tlw 

 reign of Tiberius, an earthquake happened, which over- 

 threw twelve towns in Asia ; and in his second book 

 he mentions an earthquake which overthrew 100 towns 

 in Lybia. In the time of Trajan, the town of Antio- 

 chus, and a great part of the adjacent country, were 

 swallowed up by an earthquake ; and in the time of 

 Justinian, in 528, it was again destroyed by a second, 

 with upwards of 40,000 of its inhabitants. And, sixty 

 years after in the time of Saint Gregory, it felt the ef- 

 fects of a third earthquake, with the loss of 60,000 of 

 its inhabitants. In the time of Saladin, in 1182, most 

 of the towns of Syria and Jerusalem were distroyed by 

 the same cause. In Calabria and Poh, there have 

 been more of them than in any other part of Europe. 



