III. An Account of the great Earthquake experienced in Chile on the 20 tli of February, 
1835 ; with a Map. By Alexander Caldcleugh, Esq. F.R.S. F.G.S., 8$c. 
Received October 15, — Read November 26, 1835. 
The phenomena attending this great disturbance of the surface of the earth have 
been so varied, and the extent of its effects so considerable, that I should almost 
deviate from my duty if I did not endeavour to draw up and transmit to the Royal 
Society some account of a convulsion which has laid in ruins three provinces, and 
caused incalculable damage to the southern part of this country. I am the more 
inclined to take this step from a happy concurrence of circumstances having drawn 
several scientific observers to Concepcion shortly after the catastrophe, who have 
obligingly confided their notes to me. I trust therefore the Royal Society will not 
consider that I am about to trespass upon its time. 
An idea, in some degree fanciful, prevailed for some time after the conquest of 
these countries by the Spaniards, that these convulsions of the earth’s crust occurred 
at intervals of a century ; afterwards it was supposed that about fifty years was the 
term which usually elapsed between great shocks ; but, since the commencement of 
this century, the repeated catastrophes which have occurred, especially in the 
years 1812 in Caraccas, 1818 in Copiapo, 1822 in the province of Santiago, 1827 in 
Bogota, 1828 in Lima, 1829 in Santiago, and 1832 in Huasco, have prepared the 
minds of the inhabitants to expect at all times these frightful oscillations of the 
earth, which, although they cause little sensation at first, after some time affect the 
nerves in a manner not easy to account for by ordinary causes. That they hap- 
pen at all times and in all states of the atmosphere seems clearly decided. The 
finest weather, and the most variable, equally prevail at the moment ; but many are 
the fancied signs by which the coming earthquakes are predicted, and in the faith of 
which the inhabitants confide, as they think their experience bears them out. While 
some place great confidence in rats running violently over the ceilings of the room, 
others prepare for a shock when they observe the stars twinkling more than usual, 
and all fears are removed when much lightning coruscates in the Cordillera. As far 
as my own observations go, little reliance can be placed on the two former prognostics ; 
something more certain seems to be due to the latter. A few hours previous to the 
earthquake which I am about to describe, immense flocks of sea birds proceeded 
from the coast towards the Cordillera, a circumstance which occurred prior to the 
great shock of 1822 ; and it is affirmed by too many respectable persons not to be 
