114 GEOLOGY [Chap. IX 



Letter 479 portions of S. America. I have no record of any coinci- 

 dences between shocks there and in Europe. Humboldt, by 

 his table in the Pers. Narrative (Vol. IV. p. 36, English 

 Translat.), seems to consider the elevation of Sabrina off 

 the Azores as connected with S. American subterranean 

 activity : this connection appears to be exceedingly vague. 

 I have during the past year seen it stated that a severe shock 

 in the northern parts of S. America coincided with one in 

 Kamstchatka. Believing, then, that such coincidences are 

 purely accidental, I neglected to take a note of the reference ; 

 but I believe the statement was somewhere in Ulnstitut for 

 1839. 1 I was myself anxious to see the list of the 1200 shocks 

 alluded to by you, but I have not been able to find out that 

 the list has been published. With respect to any coin- 

 cidences you may discover between shocks in S. America and 

 Europe, let me venture to suggest to you that it is probably 

 a quite accurate statement that scarcely one hour in the year 

 elapses in S. America without an accompanying shock in 

 some part of that large continent. There are many regions 

 in which earthquakes take place every three and four days ; 

 and after the severer shocks the ground trembles almost 

 half-hourly for months. If, therefore, you had a list of the 

 earthquakes of two or three of these districts, it is almost 

 certain that some of them would coincide with those in 

 Scotland, without any other connection than mere chance. 



My paper will be published immediately in the Geo/. 

 Transactions, and I will do myself the pleasure of sending 

 you a copy in the course of (as I hope) a week or ten days. 

 A large part of it is theoretical, and will be of little interest 

 to you ; but the account of the Concepcion shock of 1835 will, 

 I think, be worth your perusal. I have understood from Mr. 

 Lyell that you believe in some connection between the state 

 of the weather and earthquakes. Under the very peculiar 

 climate of Northern Chile, the belief of the inhabitants in such 

 connection can hardly, in my opinion, be founded in error. 

 It might possibly be worth your while to turn to pp. 430 — 433 



1 LInstitut, Journal General des Society's et Travaux Scientifiques de 

 la France et de I'fctranger, Tome VIII. p. 412, Paris, 1840. In a note 

 on some earthquakes in the province Maurienne it is stated that they 

 occurred during a change in the weather, and at times when a south 

 wind followed a north wind, etc. 



