320 CHARLES DARWIN 



a party of fugitive royalists had cut down fourteen years 

 ago ; and taking this as a criterion, I should think a bole a 

 foot and a half in diameter would in thirty years be changed 

 into a heap of mould. 



February 20th. This day has been memorable in the 

 annals of Valdivia, for the most severe earthquake experi- 

 enced by the oldest inhabitant. I happened to be on shore, 

 and was lying down in the wood to rest myself. It came on 

 suddenly, and lasted two minutes, but the time appeared 

 much longer. The rocking of the ground was very sensible. 

 The undulations appeared to my companion and myself to 

 come from due east, whilst others thought they proceeded 

 from south-west: this shows how difficult it sometimes is to 

 perceive the directions of the vibrations. There was no diffi- 

 culty in standing upright, but the motion made me almost 

 giddy: it was something like the movement of a vessel in a 

 little cross-rip*ple, or still more like that felt by a person skat- 

 ing over thin ice, which bends under the weight of his body. 



A bad earthquake at once destroys our oldest associations : 

 the earth, the very emblem of solidity, has moved beneath 

 our feet like a thin crust over a fluid; one second of time 

 has created in the mind a strange idea of insecurity, which 

 hours of reflection would not have produced. In the forest, 

 as a breeze moved the trees, I felt only the earth tremble, but 

 saw no other effect. Captain Fitz Roy and some officers 

 were at the town during the shock, and there the scene was 

 more striking; for although the houses, from being built of 

 wood, did not fall, they were violently shaken, and the boards 

 creaked and rattled together. The people rushed out of 

 doors in the greatest alarm. It is these accompaniments that 

 create that perfect horror of earthquakes, experienced by all 

 who have thus seen, as well as felt, their effects. Within the 

 forest it was a deeply interesting, but by no means an awe- 

 exciting phenomenon. The tides were very curiously affected. 

 The great shock took place at the time of low water; 

 and an old woman who was on the beach told me that the 

 water flowed very quickly, but not in great waves, to high- 

 water mark, and then as quickly returned to its proper level ; 

 this was also evident by the line of wet sand. The same kind 

 of quick but quiet movement in the tide happened a few 



