602 C. DarwiNj Esq., on Volcanic 



Transactions for 1836, also, contains a memoir on this subject by Mr. Cald- 

 cleugh. I must, therefore, refer to these authors, whose statements, as far as 

 I had an opportunity of observing, I can fully corroborate, for a particular de- 

 scription of the earthquake itself, and of the changes of level which accom- 

 panied it in the neighbourhood of Concepcion. I will add only a few details, 

 and will then proceed to describe the manner in which the southern volcanos 

 of Chile were affected during the shock. 



The island of Juan Fernandez, situated 360 geographical miles N.E. of 

 Concepcion, seems to have been more violently shaken than the opposite 

 shore of the mainland, and at the same time a submarine volcano, which con- 

 tinued in action during the day and part of the following night, burst forth 

 near Bacalao Head, where the depth was afterwards ascertained to be sixty- 

 nine fathoms. This fact possesses a peculiar interest, inasmuch as during 

 the earthquake of 1751, which utterly overthrew Concepcion, this island was 

 likewise affected in a remarkable manner, considering its great distance 

 from the chief seat of disturbance. If any exact record had been kept of 

 that event, many other points of resemblance would probably have been dis- 

 covered. There is a tradition, that the land was then permanently elevated, 

 and the area affected appears to have been very much the same with that 

 disturbed in Feb. 1835. Molina* also states, that the undulation travelled 

 from the southward; and in this second catastrophe the inhabitants agreed 

 in thinking that it came from S.W., or even more southerly. After an interval 

 of only eighty-four years, it is not at all improbable that the subterranean 

 forces should be directed towards the same identical points. 



Being anxious to trace the effects of the earthquake to the south, I 

 wrote, shortly after visiting Concepcion, to Mr. Douglas, a very intelligent 

 man, with whom I had become acquainted in the island of Chiloe ; and the 

 answer, which I have received since my return to England, is full of curious 

 information. 



He describes the earthquake, which appears to have been felt over the whole area at almost 

 the same minute, (as far as the clocks of the country can be relied on,) as being very violent. 

 He says, that twenty minutes before the great shock a trifling one was felt, a circumstance 

 which I did not hear of in any other part. He was at the time on the island of Caucahue, (one of 

 the many islets on the inland shore of Chiloe) and at the time wrote down the following remarks 

 in his pocket-book : " Felt an earthquake at half-past eleven o'clock, motion horizontal and slow, 

 similar to that of a ship at sea going before a high regular swell, with three to five shocks in a 

 minute, somewhat stronger than the continued motion ; direction from N.E. to S.VV. Forest trees 

 nearly touched the ground in these directions, but none fell in our vicinity ; — pocket compass placed 

 level on the ground, N. point set to lubbers' point; remarked that it vibrated during the violent 



* Compendio de la Historia del Reyno de Chile, vol. i. p. 33. 



