Natural History of Volcanos mid Earthquakes. 45 



ted hydrogen.* These last may have occasioned also the de- 

 struction of the fish in the sea, and in lakes, during earthquakes; 

 many instances of which are known. The bursting forth of 

 flames from the earth and from the sea, which is so often men- 

 tioned,f also indicates the presence of inflammable gases. How- 

 ever, although this is corroborated by the fire-damp in mines, the 

 disengagement of sulphuretted hydrogen while boring artesian 

 wells, and the not uncommon exhalations of inflammable gas from 

 the earth, yet it is difficult to account for their inflammation. This 

 difficulty would disappear, if observation had found flames only 

 to occur in really volcanic districts. J But at any rate, it is going 

 rather too far to take the explosion of fire-damp for the cause of 

 earthquakes, as Kries does.|| It is not impossible, that what has 

 been taken for flames, if not altogether an illusion, was only an 

 appearance of light, produced by the sudden expansion of highly 

 compressed gases, exactly the same as is seen when an air-gun is 

 discharged in the dark. 



The heating and boiling up of the water in the sea and in 

 lakes, the spouting up of streams of water, as well as the ejection 

 of various substances from fissures in the earth,*§i which have oc- 



holes, as rats, mice, reptiles, &c., commonly quit their abodes shortly before earth- 

 quakes. Crocodiles quit their pools in the Llanos, and remove to the continent, 

 Relat. Hist. t. v, p. 57. Von Humboldt moreover relates that dogs, goats, and 

 particularly hogs, which have a keen smell, and turn up the ground, are suddenly 

 affected, and a great number of these latter animals have been found suffocated 

 during the earthquakes in Peru. 



* Von Humboldt, ibid. t. i, p. 484, andt. ii, p. 73. Von Hoff, ibid, t. xii, p. 567, 

 t. xviii, p. 46. See also Philos. Trans, t. xlix, p. 415. 



t Von Humboldt, ibid. Gehler's Physikal. Worterbuch, newr edit., t. iii, p. 

 804. Also during the earthquake of Lisbon (Philos. Trans, ibid.) and on the isl- 

 and of Matschian, (Hist, de la Conquete des Molluques, t. iii, p. 318) the bursting 

 forth of flames is reported to have taken place. 



t Von Humboldt mentions flames which rise from time to time out of two ex- 

 tensive caverns in the ravine of the Cuchivano. This phenomenon was accom- 

 panied, during the last great earthquake at Cumana, with a continued hollow 

 subterranean noise. The flames are more especially to be seen during the rainy 

 season. 



II In his prize essay on the causes of earthquakes. 



§ Von Hoff 1. c. t. XXV, p. 73, t. xxix, p. 421. At the time of the earthquakes, 

 which destroyed a part of Italy, (1702-1703,) many rents were formed in the 

 Ahruzzi, which emitted a large quantity of stones and then troubled water. The 

 latter was thrown up higher than the trees in the neighborhood. Flames and a 

 thick smoke rose from the neighboring hills, which continued three days with 

 some interruptions. Hist, de 1' Acad. an. 1704, p. 10. During the earthquake, 



