284 Baron Humboldt on Mud- Volcanoes. 



that are more remote from the subterraneous fire shew them- 

 selves colder ; those that flow in closer proximity to the fire, 

 Avarmed by it, bring an insupportable heat to the surface which 

 we inhabit." 



As earthqiiakes are frequently accompanied by eruptions of 

 water and watery vapour, so do we perceive in the salses, or 

 the small mud- volcanoes, a transition from the alternating phe- 

 nomena presented by jets of vapour and thermal springs to the 

 great and frightful activity of hills that vomit forth lava. If 

 these, as springs of melted mineral matter, produce volcanic 

 rocks, so do the thermal springs that are charged with car- 

 bonic acid and sulphurous gas (and earthy matters), pro- 

 duce, by incessant precipitation, either horizontal beds of 

 limestone (travertin), or they form conical hillocks, as in the 

 north of Africa (Algeii'a), and the Banos of Caxamarca, on 

 the western declivity of the Peruvian Andes. In the tra- 

 vertin of Van Dieman's Land, not far from Hobart Town, 

 there are contained, according to Mr Charles Darwin, the re- 

 mains of an extinct flora. By lava and travertin, two species 

 of rock, the production of which goes on under our eyes, we 

 here indicate the grand antithesis in geognostical relations. 



Mud-volcanoes (salsen) deserve a gi'eater share of attention 

 than geologists have hitherto bestowed upon them. The ex- 

 tent of the phenomena has been overlooked, because in the 

 two states in which it presents itself to us, the one of repose 

 is that which has been principally dwelt upon ; and in this 

 state of repose mud-volcanoes often continue for centuries. 

 The production of mud-volcanoes is accompanied by earth- 

 quakes, subterranean thunder, the elevation of a whole district 

 of country, and the eruption of flames, which rise high, but 

 last only for a short time. When the mud-volcano of lok- 

 mali made its appearance in the peninsula of Abscheron, east- 

 ward from Baku, on the Caspian Sea (on the 27th of Novem- 

 ber 1827), flames burst forth, and blazed up to an extraordinary 

 height for a period of three hours ; for the next succeeding 

 twenty hours they scarcely rose three feet above the sm-face 

 of the crater that discharged the mud. The column of flame 

 mounted to such a height near the village of Baklichi, west- 

 ward from Baku, that it was seen at the distance of six (Ger- 



