392 COSMOS. 



be discovered in the immediate vicinity. Lights were seen 

 from the ship at night, no ejections of mud, but great heat 

 of the bed of the sea, and small pools of water containing 

 sulphuric acid were observed. The district merits a careftil 

 investigation, and the phenomenon stands quite unconnected 

 there, like the volcanic action of the Cerro de Buen Tiempo, 

 or of Mount Elias in the Californian Cascade range (M'Clure, 

 Discovery of the Northwest Passage, pi 99 ; Papers relative to 

 the Arctic Expedition, 1854, p. 34; Miertsching's Reise-Tage- 

 huch ; Gnadau, 1855, s. 46). 



I hav%hitherto treated the volcanic vital activities of our 

 planet in their intimate connections as if forming an ascend- 

 ing scale of the great and mysterious phenomenon of a reac- 

 tion of its fused interior upon its surface, clothed with ani- 

 mal and vegetable organisms. I have considered next in 

 order to the almost purely dynamic effects of the earthquake 

 (the wave of concussion) the thermal springs and salses, that 

 is to say, phenomena produced, with or without spontaneous 

 ignition, by the permanent elevation of temperature commu- 

 nicated to the water-springs and streams of gas, as well as 

 by diversity of chemical mixture. The highest, and in its 

 expressions the most complicated grade of the scale is pre- 

 sented by the volcanoes, which call into action the great and 

 varied processes of crystalline rock-formation by the dry 

 method, and which consequently do not simply reduce and 

 destroy, but appear in the character of creative powers, and 

 form the materials for new combinations. A considerable 

 portion of very recent, if not of the most recent, mountain 

 strata is the work of volcanic action, whether effected, as in 

 the present day, by the pouring forth of molten masses at 

 many points of the earth at peculiar conical or dome-shaped 

 elevated stages, or, as in the early years of our planet's exist- 

 ence, by the immediate issuing forth of basaltic and trachytio 

 rock by the side of the sedimentary strata, from a net-work of 

 open fissures, without the intervention of any such structures. 



In the preceding pages I have most carefully endeavored 

 to determine the locality of the points at which a communi- 

 cation has long continued open between the fluid interior of 

 the earth and the atmosphere. It now remains to sum up 

 the number of these points, to separate out of the rich abund- 

 ance of the volcanoes which have been active in very re- 

 mote historical periods those which are still ignited at the 

 present day, and to consider these according to their division 

 into continental and insular volcanoes. If all those which, 



