VOLCANOES AND 



case of volcanoes near the sea. In the case of lava 

 pouring from a volcano, it is observed that the molten 

 rock emits vast quantities of vapour, of which, according 

 to Sir Archibald Geikie, 999 parts in 1000 are steam. 

 The enormous volume of these has been brought home to 

 us in recent years by the behaviour of the volcano Mount 

 Pelee, from which for several years after the great erup- 

 tion which devastated Port au Prince the vapours rose 

 in clouds that were to be measured in cubic miles. 

 Similar observations about the quantities of vapour 

 ejected by volcanoes have been made in Japan. 



While speaking of Mount Pelee we may recall another 

 phenomenon connected with it, which also appears to 

 bear out the supposition that in the volcano's activity 

 the^action of steam takes a veryTairge^sEarei Af'terTEs 

 first outburst Mount Pelee ^continued lo pour out lava 

 and great quantities of vapour, as if like some gigantic 

 cauldron it were being fed with fresh supplies of water ; 

 and there in the early March of the following year a 

 most amazing thing took place, under the very eyes of a 

 celebrated investigator of volcanoes, now dead, Professor 

 Angelo Heilprin, who was remaining on the island. A 

 great obelisk of andesite (a stone not unlike basalt) was 

 forced up from the crater. It rose rapidly, as much as 

 five feet a day; and it reached altogether a height of 

 840 feet above the crater's lip. It was calculated to be 

 about 300 feet in diameter at its base. It continued to 

 push itself up for some months, sometimes sinking a little, 

 sometimes rising like a colossal piston above a steam 

 boiler. Its greatest height was 1100 feet above the 



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