208 C0SM03. 



'llie diflerent volcanoes over the earth's burface, when they 

 are considered independently of all climatic differences, are 

 acutely and characteristically classified as central and linear 

 volcanoes. Under the first name are comprised those which 

 constitute the central point of many active mouths of erup- 

 tion, distributed almost regularly in all directions ; under the 

 second, those lying at some little distance from one another, 

 forming, as it were, chimneys or vents along an extended 

 fissure. Linear volcanoes again admit of further subdivision, 

 namely, those which rise like separate conical islands from the 

 bottom of the sea, being generally parallel with a chain of 

 primitive mountains, whose foot they appear to indicate, and 

 those volcanic chains which are elevated on the highest ridges 

 of these mountain chains, of which they form the summits. =^ 

 The Peak of Tenerifle, for instance, is a central volcano, being 

 the central point of the volcanic group to which the eruption 

 of Palma and Lancerote may be referred. The long, rampart- 

 like chain of the Andes, which is sometimes single, and some- 

 times divided into tM^o or three parallel branches, connected 

 by various transverse ridges, presents, from the south of Chili 

 to the northwest coast of America, one of the grandest in- 

 stances of a continental volcanic chain. The proximity of 



where there is a notice of the celebrated burning mud of the Lelantine 

 plains, in Euboea, i., p. 58, Casaub. ; and Appian, De Bello Civiii, v., 

 114. The blame which Aristotle throws on the geognostical fantasies 

 of the Phsedo {Meteor., ii., 2, 19) is especially applied to the sources of 

 ihe rivers flowing over the earth's surface. The distinct statement of 

 Plato, that "in Sicily eruptions of wet mud precede the glowing (lava) 

 Btream," is very remarkable. Observations on jEtna could not have led 

 to such a statement, unless pumice and ashes, formed into a mud-like 

 mass by admixture with melted snow and water, during the volcano- 

 electric storm in the crater of eruption, were mistaken for ejected mud. 

 It is more probable that Plato's streams of moist mud {yypov •nrjlov 

 ■KOTaixot) originated in a faint recollection of the salses (mud volcanoes) 

 of Agrigentum, which, as I have already mentioned, eject argillaceous 

 mud with a loud noise. It is much to be regretted, in reference to this 

 subject, that the work of Theophrastus Trtpt pvanoc tov ev ^ike^-ic, On 

 the Volcanic Stream in Sicily, to which Diog. Laert., v., 49, refers, has 

 not come down to us. 



* Leopold von Buch, Physikal. Besclireib. der Canarischen Insein, s. 

 326-407. I doubt if we can agree with the ingenious Charles Darwin 

 (Geological Observations on Volcanic Islands, 1844, p. 127) in regard- 

 ing central volcanoes in general as volcanic chains of small extent on 

 parallel fissures. Friedrich Hoffman believes that in the group of the 

 Lipari Islands, which he has so admirably described, and in which two 

 eruption fissures intersect near I'anaria, he has :fouud an intermediate 

 link between the two principal modes in which volcanoes appear, 

 namely, XXvi central volcanoes and volcanic chains of Von Buch (Pog- 

 geudorf, Annalcn der Phydk, bd. xxvi., s. 81-83j. 



