in EARTHQUAKES HAVE NATURAL CAUSES 229 



at these is in no case free from fear. As the 

 cause of the fear is ignorance, is it not worth while 

 to gain the knowledge that will dispel it ? How 

 much better it would be to inquire into the causes 

 of the alarming sights, to bend, in fact, our whole 

 mind to the task ? Nothing, surely, could be found 

 more deserving than that, of having the mind's 

 energies not only lent to it, but devoted to it. 



IV 



LET us ask ourselves, therefore, what it is that stirs i 

 the earth to its foundation, what moves a mass of 

 such weight, what it is that is stronger than the 

 earth, and that in its violence can shake such a 

 load. Let us inquire why at one time the earth 

 trembles, at another is loosened and sinks, and 

 again is divided into parts and opens a chasm ; 

 or why on some occasions the intervals of destruction 

 are prolonged, on others are suddenly cut short. 

 What is the cause why it now consigns to its 

 depths rivers of renowned greatness, and now causes 

 fresh rivers to issue ? why does it sometimes open 

 up springs of hot water, sometimes freeze them 2 

 with cold ? and why at times are fires caused to 

 shoot out through some hitherto unknown opening 

 in mountain or crag, while sometimes well-known 

 fires, that have been famous for centuries, are sup- 

 pressed ? The earthquake produces a thousand 

 strange sights, changing the aspect of the ground, 

 levelling mountains, elevating plains, exalting 

 valleys, raising new islands in the deep. What are 

 the causes that bring these things to pass ? That 

 is a subject well worthy our discussion. What, you 



