Baron Humboldt on Mud- Volcanoes. 285 



man) miles. Great blocks of stone, torn from their foundations 

 beneath, were scattered widely around. Similar blocks are 

 observed about the now slumbering mud-volcanoes of Monte 

 Zibio, near Sassuolo, in the north of Italy. The second state, 

 or that of activity, has continued for 1500 years in the mud 

 volcano of Girgenti (Macalubi), in Sicily, which is described 

 by the ancients. Many conical hillocks, of eight, ten, and 

 even thirty feet high, though the height, as well as the form, of 

 these varies at different times, are there seen arranged near 

 one another. From the superior very small basin, which is 

 full of water, along with the periodic escapes of gas, there are 

 periodic streams of clayey mud discharged. The mud of these 

 volcanoes is generally cold, but occasionally, as at Damak, in 

 the province of Samarang, island of Java, it is of high tem- 

 perature. The gases, which escape with a rushing noise, are 

 also of different kinds — hydrogen gas, mixed with naphtha ; 

 carbonic acid ; and, as Parrot and I ascertained, (in the penin- 

 sula of Taman and the South American Volcancitos de Tur- 

 baco), almost pure nitrogen gas. 



Mud-volcanoes, after the first forcible outburst of flame, 

 which perhaps is not common to all in the same measure, pre- 

 sent the observer with a picture of an activity of the interior 

 of the earth, that proceeds incessantly but feebly. The com- 

 munication with the deep strata, in which a high temperature 

 prevails, is speedily interrupted again ; and the cold discharges 

 of mud- volcanoes seem to indicate that the seat of the pheno- 

 menon, in its state of continuance, cannot be very remote from 

 the surface. The re-action of the interior of the earth upon 

 its outer crust is exhibited in a very different degree of force 

 in the proper volcanoes, or burning mountains; in other words, 

 in those points of the earth where a permanent communication, 

 or, at all events, a communication that is renewed from time 

 to time, is established between the surface and the deep 

 focus of ignition. We must carefully distinguish between 

 more or less exaggerated volcanic phenomena, such as earth- 

 quakes, hot springs and jets of steam, mud-volcanoes, the 

 rising up of bell and dome-shaped unopened trachytic moun- 

 tains, the opening of these mountains, or the upheaval of 

 basaltic beds as craters of elevation, lastly, the rise of a per- 



