170 voi.CAi^ros. 



liave never, witliin the memory of man, been in an active state, or at 

 least we have no record of their eruptions, if any have occurred j but 

 as they have craters like the active, are surrounded by lava which has 

 flowed from them, and other products, which have been ejected, and yet 

 emit vapors and gases, we cannot be mistaken as to their former char- 

 acter. Such are called dormant volcanos ; the probability being that 

 they never will again assume a state of activity, but yet the probability 

 remaining that they may hereafter become a terror to those persons, who 

 have dared to erect their dwellings upon their sides, and-even in iheir very 

 craters. Such had been the case with Monte Somna, Italy. The cities 

 of Herculaneum and Pompeii had been built on its ilanks, their streets 

 paved, and the walls of their edifices raised with the old lava, and the in- 

 habitants secure and given up to luxury and pleasure, and fearing no evil, 

 when unexpectedly, in A. D. 79, Vesuvius, a new crater within the old 

 Somna, was Ibrmed, from which the lava ingulphed the nearer Pompeii, 

 and the ashes and scoriae overwhelmed the farther Herculaneum, 



Distribution. These one hundred and sixty-three active vents, the 

 many which are dormant, and the yet imperfectly known submarine volca- 

 nos, are distributed without much partiality over the earth's surface. We 

 find them under the Equator, in the temperate and in the frigid zones, on 

 the Eastern and Western Continents, and in every ocean. They seem, 

 however, nearly all to have some regularity of connection with each other. 

 The great chain of American mountains, from Terra del Fuego, at the 

 southern point of America, throughout its whole length to the pro- 

 montory of Analaska, seems to conceal a continuous stratum of fire, 

 which, here and there at the separate volcanic vents, sends forth into the 

 atmosphere a portion of its burning mass. From Analaska this chain 

 passes off into the Pacific ocean through the Aelutian or Fox Islands, 

 thence into Kamtskatka,and, through the mountains of Siberia and Tar- 

 tary, into those of Asia Minor, Syria, and Arabia, thus forming one A'ast 

 arch of fire. From one leg of this arch, in the northern parts of South 

 America, there passes off a branch to the North and North-east, through 

 the West India islands, towards the Azores on the West of Spain. — 

 From the Eastern leg there pass off two branches, the one from South- 

 ern Asia, through Sumatra, Java, and the islands of Australia and Polen- 

 esia, ; the other from Western Asia through the islands of the Mediter- 

 ranean, and the mountains of Italy, &c., into the Atlantic at the Cape de 

 Verd, Canary Isles, and the Azores, thus forming a direct connection 

 between the great American and Asiatic chains. Besides these, we might 

 notice the vents of Iceland, of the Sandwich Islands, and many others, 

 which pour fortli their fires from amidst the waters of the several oceans. 



