GEOLOGY. 663 



knows the monster he proposes to face; its fury is announced 

 by warning signs, whilst the earthquake, in the twinkUng 

 of an eye, entirely annihilates a large town. 



The celebrated earthquake of Lisbon took j^lace the 

 1st of November, 1755. Nothing had occurred to make 

 men suspect such an occurrence, when, at five and twenty 

 minutes to ten in the morning, at a time when all the 

 people were quietly preparing themselves for business, a 

 frightful subterranean noise struck all the inhabitants with 

 stupefaction, and six minutes afterwards this great city 

 was only a heap of ruins, under which lay an immense 

 number of victims. 



In the catastrophe of Messina, in 1783, the movement 

 was still more rapid : in two minutes the town was utterly 

 overturned, and, to add to the horror, fire devoured the 

 ruins which the earthquake had heaped up. 



But if these shocks thus concentrate their principal 

 action upon one point — if a city collapse entirely without 

 the neighbouring districts sufi^ering any notable damage — 

 volcanic action, on the other hand, is sometimes so power- 

 ful that it shakes the crust of the earth from one pole 

 to another. Thus all Europe and part of Africa were 

 shaken when the commotion of Lisbon took place. The 

 Alps and the Pyrennees trembled to the base, the sea 

 rose and fell on the coast of Sweden, Norway, the British 

 Isles, and also upon those of America. At the time when 

 Lisbon collapsed all the richest cities of Morocco were 

 almost totally destroyed. Near the capital of this state an 

 oasis with 8000 or 10,000 inhabitants disappeared. 



Earthcj[uakes are sometimes accompanied l)y very 

 unwonted phenomena. Some curious ones were noticed 

 during that which ravaged all Calabria in 1785. Accord- 

 ing to Hamilton, mountains were seen to rise at one 



