ON ITS EXTERIOK. VOLCANOES. 261 



canic system. In the richly imaginative geological 

 picture of the interior of the earth in Plato's grand 

 contemplation of Nature, in the Phasdo (pp. 112- 

 114), this connected action is, with still greater boldness, 

 extended to all volcanic systems. In it the lava-streams 

 draw their supplies from the Pyriphlegethon, where, 

 " after it has often rolled round and round beneath the 

 earth," it pours itself into Tartarus. Plato says expressly, 

 that in " the fire-vomiting mountains, where such are 

 found on the earth, small portions of the Pyriphlegethon 

 are blown out." (OVTO? S' scrlv ov sTrovopd^ovcn Hvpi- 

 ^>\sysdovra, ov /cal ol pva/css diroa-Trdo-^ara dvatyva-OHTiv, 

 OTTTJ av TV-^WCTL rrjs 777$.) The expression (page 113, B.), 

 driving out with violence, may be understood to refer 

 to the motive force of the previously enclosed and sud- 

 denly and forcibly escaping wind, on which subsequently 

 Aristotle, in his "Meteorology/' founded his whole theory 

 of volcanic action. 



In accordance with these views, thus common to 

 ancient and modern times, the grouping of volcanoes is 

 even more characteristically marked in linear arrange- 

 ment, than when they are found around a single central 

 volcano. It is most striking where it depends on the 

 situation and extent of very long and mostly parallel 

 fissures. Thus, in the New Continent, to cite only the 

 most important series having the most numerous mem- 

 bers, we find the linear groups of Central America and 

 Mexico, of New Granada and Quito, of Peru, Bolivia, 

 and Chili ; and in the Old Continent the groups of the 

 Sunda Isles (the southern Indian Archipelago, espe- 

 cially Java), the peninsula of Kamtschatka and its 

 continuation in the Kurile Islands, and the Aleutian 



