604 C. Darwin, Esq., on Volcanic 



The volcano of Osorno had been in a state of moderate activity for at least forty-eight hours 

 previously ; Minchinmadom in much the same gentle action as for the last thirty years ; and the 

 Corcovado had been quiet during the whole previous twelve months. " At the moment of the 

 shock, Osorno threw up a thick column of dark blue smoke, and directly that passed, a large crater 

 was seen forming on the S.S.E. side of the mountain ; it boiled up lava, and threw up burning stones 

 to some height, but the smoke soon hid the mountain. When seen again a few days afterwards, it 

 showed very little smoke by day, but by night, the new crater, as well as the old one on its trun- 

 cated summit, shone with a steady light. This volcano appears to have remained in activity 

 throughout the year. The action of Minchinmadom was similar to that of Osorno : two curling 

 pillars of white smoke had been observed all the morning ; but during the shock, numerous small 

 chimneys seemed to be smoking within the great crater, and lava was thrown out of a small one 

 just above the lower verge of the snow. Eight days afterwards this little crater was extinct ; but 

 at night five small red flames were seen in a line, equidistant from each other, like those in the 

 streets of a village. By the 1st of March its activity was much diminished ; but on the 26th there 

 was a smart earthquake, and at night the five fires were again seen. A fortnight afterwards the 

 tops of fifteen conical hills could be seen within the wall of the great crater, and at night nine steady 

 fires, of which seven were in a line, and two straggling." 



At the time of the great shock, the Corcovado showed no signs of activity, nor was it heard in 

 action after the Cordillera were hidden in the clouds. Mr. Douglas, however, states, that when 

 that volcano was visible a week afterwards, the snow was seen to have been melted around the 

 N.W, crater. On Yantales, a lofty mountain south of the Corcovado, three black patches having 

 the appearance of craters were observed above the snow-line ; and Mr. Douglas did not recollect 

 having seen them before the earthquake. Bearing in mind, that on many occasions, the melting of 

 the snow on a volcano has been the first indication of a fresh period of activity, and that, as 1 

 shall presently show, the eruptions of the Corcovado and Orsono are sometimes co-instantaneous, 

 I think there can be little doubt that these appearances prove the effects of the great convulsion 

 of the 20th of February to have been felt by these, the most southern volcanos in America. 



Mr. Douglas states, that on the night of November 11th (ten months after the overthrow of 

 Concepcion), Osorno and Corcovado both burst out in violent action, throwing up stones to a 

 great height, and making much noise. He subsequently heard, that on the same day, Talca- 

 huano, the port of Concepcion, little less than 400 miles distant, was shaken by a severe earth- 

 quake. This latter statement has since been confirmed to me by a gentleman, who was at the 

 time resident in Chile. Here, then, we have a repetition of the same connected action, which was 

 displayed in so remarkable a manner on the 20th of February. Mr. Douglas in conclusion adds, 

 that on December the 5th his " attention was arrested by the grandest volcanic spectacle he had 

 ever beheld ; the S.S.E. side of Osorno had fallen in, thus uniting the two craters, whichappeared 

 like one great river of fire. Enormous quantities of ashes and smoke were erupted during the 

 succeeding fortnight." 



It is therefore evident, that the volcanic chain from Osorno to Yantales (a length of nearly 150 

 miles) was affected not only at the moment of the great shock of February 20, 1835, but remained 

 in very unusual activity during many subsequent months. 



Again, on November 7, 1837, two years and three quarters after the overthrow of Concepcion, 

 both Valdivia and San Carlos, the capital of Chiloe, were violently convulsed, even more so, ac- 

 cording to M. Gay*, than in 1835, or on any former recorded period ; this shock was sufficiently 



* Comptes Rendus, 1838. Seance Juin 11. 



