Volcanos and Earthquakes. 61 



tion the western declivity of the Teutoburger Wald, in which 

 such considerable rivers have their source; the Jura moun- 

 tains ; and the Gcrmni.* The volcanic inundations, of which 

 Von Humboldt gives such extraordinary cxamples,t are an 

 additional evidence of the existence of such great subterranean 

 accumulations of water, in the vicinity of volcanos. Lastly, 

 we have, further, examples of volcanos coming into action 

 after violent storms of rain ; for instance, the Mer-Api, in 

 Java.X In the Andes of Quito, the Indians imagine they have 

 observed, that the quantity of percolating snow-water increases 

 the activity of volcanos.§ Can it, then, any longer be doubted, 

 that the proximity of the ccean is by no means a necessary con- 

 dition in the production of volcanic phenomena ? But all that 

 has been said respecting the channels by which the sea-water is 

 admitted to the volcanic focus, holds equally good with respect 

 to those admitting springs or rain-water ; only with this dif- 

 ference, that, in the more lofty volcanos of Aviei'ica, the vol- 

 canic focus may be imagined much higher, and yet columns of 

 water of considerable pressure will not be wanting, provided 

 those accumulations of water be situated at a great height in 

 the mountains. 



The same power by which masses of lava are forced up, 

 sometimes so as to reach the surface and flow over it, or in 

 other cases becoming solidified in their channels, will also raise 

 whole mountains. These elevations may take place through 



* Von Humboldt (Reise, t. iii. p. 229), mentions several rivers which lose 

 themselves in the gneiss rocks. When these gneiss mountains were up- 

 raised, considerable caverns may have been formed, which were afterwards 

 filled with water. 



t Annal. de Chim. et de Phys. t. xxvii, p. 128. This circumstance, how- 

 over, must bo considered, that the strong heat over the active volcano di- 

 lates the atmosphere, and produces a rising stream of air. The consetpience 

 of that is an influx of air from all sides. But this air is aecomi)anied with 

 moisture, which, rising with it, is condensed in tlie higher regions of the 

 atmosphere, and falls down in showers. Therefore, an active volcano affords 

 not only water, which immediately issues from its interior, but it also de- 

 prives all the environs of water. Du Carta sur les iuondat. Volcaniques. 

 Journ. de Physique, t. xx. p. 103. 



It: Memoir of the Conquest of Java. London, 1815, p. 40. 



§ Von Humboldt's Reise, t. i. p. 263. 



