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battle of the elements, as the crater thrusts its burning mouth out 

 of the deep waters, like some fabled fiery dragon of old. It was 

 noticed even by the ancient Eomans, Strabo, I believe, that oceanic 

 islands were almost invariably of volcanic origin. A few of these 

 indeed have risen in our own time, for example, Graham's Island, 

 which suddenly appeared in full eruption in the Mediteranean, it 

 was however only three months above water, and during that time 

 it was claimed and named by seven different nationalities ! When 

 we calculate that at a depth of 1,000 fathoms the pressure on each 

 individual square inch of the sea bottom is no less than one ton, it 

 explains the fact of so few volcanoes existing in mid-ocean, 

 although the sea holds to the surface of the earth a proportion of 

 nearly three to one. 



Closely allied to volcanoes are Geysers, or hot springs, of which 

 I saw excellent examples (probably the best in the world), in 

 Iceland. These are, essentially, water volcanoes ; there is the 

 same crater, the same communication with a reservoir of heated 

 fluid, and the same forcible expulsion by the same force, steam. 

 The most remarkable is the Great Geyser, which has a basin 

 or crater as symmetrically formed as though chiselled by art, 

 and a central pipe of 16ft. diameter, whence a body of boiling 

 water is ejected at uncertain intervals some hundreds of feet into 

 the air. There was another geyser on a smaller scale called Strokr, 

 out of which we could always " get a rise " by choking up its funnel 

 with about a small cartload of turf, when, after an interva of a 

 few minutes of sputtering and choking, it would be expelled with 

 the greatest violence, followed by a lofty column of boiling water. 

 You will understand the principle of their action by a diagram I 

 will make on the black board. And yet, disastrous as are their 

 effects, and appalling the accompaniments of earthquakes and 

 volcanoes, their action is, on the whole, beneficial, nor are the 

 fatalities attending them to be compared to the losses from wars, 

 pestilences, and famines. It is generally found that where volcanic 

 action is most frequent the country is most fertile and thickly 

 populated, and although large tracts are occasionally laid waste by 

 eruptions of lava, yet the disintegration of volcanic products makes 

 the most fertile and productive soil, especially for vines. Volcanoes 

 have been well caUed the " Safety valves " of the earth, for were 

 it not for them the crust of the globe would be constantly shattered 

 and convulsed. But more than all, volcanic energy is absolutely 

 needful to the very existence of our race, by counteracting the 

 levelling influence of air and water, by building up and elevating 

 large tracts of land, thus affording another exemplification, if 

 one were needed, of the ever watchful Providence which so often 

 turns apparent disasters into blessings. 



