MUD VOLCANOES. 



revolutions of the globe, have supplied those inexhaustible stores 

 of mineral fuel which have, through the application of science, 

 become mechanical agents of infinite power, as well as sources 

 of artificial light and heat. 



53. These prodigious volumes of carbonic acid also supplied 

 other purposes in the terrestrial economy at that early period. 

 Entering into combination with lime, which also prevailed in 

 abundance, lime-stone rocks of every kind, including those 

 beautiful marbles which have become so important a material in 

 the industrial and ornamental arts, were produced ; for these rocks, 

 as is well known, are nothing but carbonates of lime, the carbonic 

 acid constituting nearly half of their entire mass. 



54. The transition from the ejection of gases and liquids to that 

 of molten rocks exhibited in the effects of volcanoes, is marked 

 by the intermediate phenomena of the ejection of hot mud. 

 According to Humboldt, although SALSES or mud volcanoes in their 

 normal state present little to arrest attention, their origin is 

 characterised by the imposing phenomena of earthquakes, sub- 

 terranean thunder, the upswelling of vast tracts of country, and 

 the ejection of lofty jets of flame. A recent and well-observed 

 example of such a phenomenon is presented in the case of the mud 

 volcano of Jokmali, on the peninsula of Apscheron, east of Baku 

 on the shores of the Caspian sea. This peninsula has always been 

 the theatre of singular subterranean phenomena, and flames have- 

 so frequently, in past times, issued from the ground upon it, that 

 it has been regarded with veneration by the oriental fire- 

 worshippers. On this peninsula on the 27th November, 1827,. 

 flames blazed up from the ground to so great a height that they 

 were seen at the distance of 24 miles, in which state they con- 

 tinued for three hours, after which they decreased to the height of 

 three feet. They issued from a crater which was formed by their 

 ejection, and continued to burn in that way for 20 hours. This- 

 ended in the ejection of enormous fragments of rock, and 

 quantities of hot mud. 



55. Of mud volcanoes of more remote origin we have examples in. 

 the case of the Monte Zibio, near Sassuolo in the Duchy of Modena, 

 and the salse near ^rirgenti, in Sicily. Fragments of rocks like those 

 ejected by Jokmali may be seen around the former. The salse 

 has continued in the secondary state of activity for fifteen hundred 

 years, descriptions of it at that early epoch having come down to 

 us. It consists of several cone-shaped mounds, varying in height 

 from eight to thirty feet, "and subject to constant change, not only 

 in height but in shape. Small craters are formed at the summit 

 of the cones, which contained more or less water, and from which 

 gas from time to time is disengaged. 



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