278 Baron Humboldt on Gas Springs. 



phur fumes, and, more rarely, of sulphureous and hydro-cliloric 

 acid vapours. Such emanations from fissures in the ground, 

 do not only indicate the dominion of volcanoes long extinct 

 or still burning ; they are farther observed exceptionally in 

 districts in which neither trachyte nor any other volcanic rock 

 appears at the surface. In the Andes of Quindiu, I have seen 

 sulphur precipitated from hot sulphureous vapours issuing out 

 of mica-slate, at a height of 6410 feet above the level of the 

 sea ; whilst the same, and, as it used to be regarded, primitive 

 rock, in Cerra Cuelo, near Ticsan, south of Quito, exhibits an 

 enormous bed of sulphur in pure quartz. 



Of all the gaseous springs which the earth pours forth, those 

 of carbonic acid (mofetten) are still, at the present time, the 

 most important, both in number and extent. Germany, in 

 her deeply- cut valleys of the Eifel, in the neighbourhood of 

 Lake Lach, in the Kesselthal of Wehr, and in Western Bohe- 

 mia, as also in the burning foci of the primeval world, or their 

 vicinity, shews us these effusions of carbonic acid as a kind of 

 last effort of volcanic activity. In former epochs, where, with 

 a higher temperature of the earth, and the frequency of fissures 

 yet unfilled, the processes which we are here describing pro- 

 ceeded more actively where carbonic acid gas and watery 

 vapours were mingled with the atmosphere in larger quantities 

 than at present, the youthful vegetable world, as Adolph 

 Brongniart has acutely observed, must have attained almost 

 everywhere, and independently of geographical position, to 

 the most rank luxuriance and evolution of its organs. In 

 the ever hot, ever moist atmosphere, surcharged with carbonic 

 acid, vegetables must have found such vital excitement, such 

 superfluity of nourishment, as enabled them to supply the 

 material of those beds of coal and lignite, the exhaustion of 



vegetable remains, unless some fucoids may Lave decomposed in the 

 same strata. The invisible gas makes its way in countless bubbles 

 through the clear transparent waters of the Niagara. On the applica- 

 tion of a lighted candle, it takes fire, and plays about with a lambent 

 flickering flame, which seldom touches the water, the gas being, at first, 

 too pure to be inflammable, and only obtaining sufiicient oxygen after 

 mingling with the atmosphere at the height of several inches above the 

 surface of the stream. — Lycll's Travels in North America, vol. ii., p. 90. — 

 Edit, of Phil. Journal. 



