ON ITS EXTERIOR. VOLCANOES. 233 



chains of mountains which traverse the Asiatic continent 

 from east to west, the Altai, the Thian-schan, the Kuen- 

 lun, and the* Himalaya, it is not the Himalaya which is 

 nearest to the sea, but the two interior chains (the Thian- 

 schan and Kuen-lun), at distances of 1600 and 720 miles 

 from the sea, which have eruptive volcanoes like Etna and 

 Vesuvius, and issues of ammoniacal gas like the volcanoes 

 of Guatimala. It is impossible not to recognise currents 

 of lava in the descriptions given by Chinese writers of 

 smoke and flame bursting from the Pe-schan, accom- 

 panied by burning masses of stone flowing as freely as 

 "melted fat," and devastating the surrounding district, in 

 the first and seventh centuries of our era. The facts thus 

 brought together, and which have not perhaps been hitherto 

 sufficiently considered, render it at least highly probable 

 that the vicinity of the sea, and access of sea water to the 

 focus of volcanic activity, are not essential conditions of 

 the breaking forth of the subterranean fire ; and that, if 

 littoral situations favour such eruptions, it is only because 

 they are on the margin of the deep sea basin, of which the 

 bed, covered only by superincumbent water, and situated 

 many thousand feet lower than the elevated terra firma of 

 the interior of continents, offers less resistance to the sub- 

 terranean forces. 



The present active volcanoes, of which the craters es- 

 lublish a communication between the interior of the 

 earth* and the atmosphere, have been opened at so late 

 an epoch, that the upper chalk strata, and all the ter- 

 tiary formations, were previously existing : this is evidenced 

 by the trachyte and the basalt which often form the sides of 

 the craters of elevation. Melaphyres extend to the middle 

 tertiary strata, having apparently been poured out also be- 



