SALSE3. 225 



they could bo seen at a distance of twenty-four miles. Knor* 

 mous masses of rock were torn up and scattered around. Sim- 

 ilar masses may be seen round the now inactive mud volcano 

 of Monte Zibio, near Sassuolo, in Northern Italy. The sec- 

 ondary condition of repose has been maintained for upward of 

 fifteen centuries in the mud volcanoes of Girgenti, the Maca- 

 hihi, in Sicily, which have been described by the ancients. 

 These salses consist of many contiguous conical hills, from 

 tjight to ten, or even thirty feet in height, subject to variations 

 of elevation as well as of form. Streams of argillaceous mud, 

 attended by a periodic development of gas, flow from the small 

 basins at the summits, which are filled with water ; the mud, 

 although usually cold, is sometimes at a high temperature, as 

 at Damak, in the province of Samarang, in the island of Java. 

 The gases that are developed with loud noise difTer in their 

 nature, consisting, for instance, of hydrogen mixed with naph- 

 tha, or of carbonic acid, or, as Parrot and myself have shown 

 (in the peninsula of Taman, and in the Volcuncitos de TuV' 

 baco, in South America), of almost pure nitrogen.* 



Mud volcanoes, after the first violent explosion of fire, which 

 is not, perhaps, in an equal degree common to all, present to 

 the spectator an image of the uninterrupted but weak activity 

 of the interior of our planet. The communication with the 

 deep strata in which a high temperature prevails is soon closed, 

 and the coldness of the mud emissions of the salses seems to in- 

 dicate that the seat of the phenomenon can not be far re- 

 moved from the surface during their ordinary condition. The 

 reaction of the interior of the earth on its external surface is 

 exhibited with totally different force in true volcanoes or igne- 

 ous mountains, at points of the earth in which a permanent, 

 or, at least, continually-renewed connection with the volcanic 

 force is manifested. We must here carefully distinguish be- 

 tween the more or less intensely developed volcanic phenom- 

 ena, as, for instance, between earthquakes, thermal, aqueous, 

 and gaseous springs, mud volcanoes, and the appearance of 

 bell-formed or dome-shaped trachytic rocks without openings' 

 the opening of these rocks, or of the elevated beds of basalt, as 



* Humboldt, Rel. Hist., t. iii., p. 502-567 ; Asie Centrale, t. i., p. \? 

 t. ii., p. 595-515; Vues des Cordilleres, pi. xli. Regarding the Maca- 

 luhi (the Arabic Makhluh, the overthrown or inverted, from the word 

 Khalaba), and on " the Earth ejecting fluid earth," see Solinus, cap. 5: 

 *' idem ager Agrigentinus eructat limosas scaturigenes, et ut vena) fon* 

 tium sufEciunt rivis subministraudis, ita in hac SiciliaR parte solo v"**>» 

 ijuam deficieute, ajterna rejectatione terram teiru e\omil " 



Iv2 



