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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 Romans, Strabo, I believe, that oceanic 
islands were almost invariably of voleanic 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 ofa 
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. Itis 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 voleanic products makes 
the most fertile and productive soil, especially for vines. Volcanoes. 
have been well called 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, voleanic 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. 
