22 1 COSMOS. 



of the earth, as ^Etna and other mountains near JSaplej may 

 teach yon. The subterranean waters rise as if through si- 

 phons. The cause of hot springs is this : waters which are 

 more remote from the subterranean fire are colder, while those 

 which rise nearer the fire are heated by it, and bring with 

 them to the surface which we inhabit an insupportable degree 

 of heat." 



As earthquakes are often accompanied by eruptions of water 

 and vapors, we recognize in the Salses,* or small mud vol- 

 canoes, a transition from the changing phenomena presented 

 by these eruptions of vapor and thermal springs to the more 

 powerful and awful activity of the streams of lava that flow 

 from volcanic mountains. If we consider these mountains as 

 springs of molten earths producing volcanic rocks, we must re- 

 member that thermal waters, when impregnated with carbonic 

 acid and sulphurous gases, are continually forming horizon- 

 tally ranged strata of limestone (travertine) or conical eleva- 

 tions, as in Northern Africa (in Algeria), and in the Banos 

 of Caxamarca, on the western declivity of the Peruvian Cor- 

 dilleras. The travertine of Van Diemen's Land (near Hobart 

 Town) contains, according to Charles Darwin, remains of a 

 vegetation that no longer exists. Lava and travertine, which 

 are constantly forming before our eyes, present us with the 

 two extremes of geognostic relations. 



Salses deserve more attention than they have hitherto ro 

 ceived from geognosists. Their grandeur has been overlooked 

 because of the two conditions to which they are subject ; it is 

 only the more peaceful state, in which they may continue for 

 centuries, which has generally been described : their origin is. 

 however, accompanied by earthquakes, subterranean thunder, 

 the elevation of a whole district, and -lofty emissions of flame 

 of short duration. When the mud volcano of Jokmali began 

 to form on the 27th of November, 1827, in the peninsula of 

 Abscheron, on the Caspian Sea, east of Baku, the flames 

 flashed up to an extraordinary height for three hours, while 

 during the next twenty hours they scarcely rose three feet 

 above the crater, from which mud was ejected. Near the 

 village of Baklichli, west of Baku, the flames rose so high that 



* [True volcanoes, as wo have seen, generate sulphureted hydrogen 

 and muriatic acid, upheave tracts of land, and emit streams of melted 

 feldspathic materials ; salses, on the contrary, disengage little else but 

 rarbureted hydrogen, together with bitumen and other products of the 

 distillation of coal, and pour forth no other torrents except of mud, 01 

 argillaceous materials mixed up with water. Daubeuey, op cit , p 

 40.] 3V. 



