238 COSMOS. 



The difiererit volcanoes over the earth's surface, 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 mouth's 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, Mdiose 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 Teneriffe, 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 two 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 Civili, v., 

 114. The blame which Aristotle throws on the geognostical fantasies 

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

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

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

 stream," is very remarkable. Observations on iEtna 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 {vypov nrjXov 

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

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

 mud w^ith a loud noise. It is much to be regretted, in reference to this 

 subject, that the work of Theophrastus Tvepi pvaKoq tov ev ^iKcTita, On 

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

 not come down to us. 



* Leopold von Buch, Physikal. Beschreib. der Canarischen Inseln, s. 

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

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

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

 })arallel 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 Panaria, he has found an intermediate 

 link between the two principal modes in which volcanoes appear, 

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

 gendorf, Annalen der Physik, bd. xxvi., s. 81-88). 



