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On this has been erected the Royal Observatory, under the superintendence of Professor Luigi Palmieri, where continuous observations are being made, by means of delicate seismometers, of the earth-tremors which precede or accompany eruptions; for it is only justice to say that Vesuvius gives fair warning of impending mischief, and the instruments are quick to notify any premonitory symptoms of a coming catastrophe.
If an observer could view the earth from the surface of the moon, he would probably each day behold one of these storms which the volcanoes send forth. In the fortnight of darkness, even with the naked eye, it would probably be possible to discern at any time several eruptions, some of which would indicate that the earth's surface was ravaged by great catastrophes.
Wuluchinski is to the southward and not volcanic, while Avatcha and Korianski, to the north and east, were smoking with a dignified air, like a pair of Turks after a champagne supper. Eruptions of these volcanoes occur every few years, and during the most violent ones ashes and stones are thrown to a considerable distance.
With these a salamander, scarcely distinguishable from the recent species, has been found, and the remains of many insects. The extinct volcanoes of Auvergne and Cantal, in central France, seem to have commenced their eruptions in the Lower Miocene period, but to have been most active during the Upper Miocene and Pliocene eras.
Only a few of the various causes that may bring about earthquakes are as yet fully understood. Earthquakes are very interesting, however, because they are often associated with the birth and growth of lofty mountain ranges. Volcanic eruptions, hot springs, and the high temperature which exists toward the bottom of deep mines show us that the interior of the earth is very hot.
In general, the farther we go back from the period of modern eruptions, the more the currents increase both in size and extent, acquiring the character of rocks, by the regularity of their position, by their division into parallel strata, or by their independence of the present form of the ground. The Peak of Teneriffe is, next to Lipari, the volcano that has produced most obsidian.
In the western cordillera, on the contrary, although much of the present form of the land is due to erosion, a vast amount is due directly to so-called "tectonic" activities such as the breaking of the crust, the pouring out of molten lavas, and the bursting forth of explosive eruptions. The character of these tectonic activities has differed widely in different parts of the cordillera.
We are, therefore, tolerably safe in considering the first eruptions to belong to the Tertiary period; but the evidence, derived as it is exclusively from plant remains, is somewhat conflicting as to the precise epoch to which the lavas and beds of tuff containing the plant-remains are to be referred.
A few hours later he was back again, looking older and shakier than ever, his wet red eyes looking like plague spots in his ashy brown visage or like volcanic eruptions in a desert of dead lava, and in husky, clicking accents he told Billy to tell the Okimow that the pills were no good not strong enough for him. "Well," I said, "he shall surely have results this time."
It is all very well to say that there have been movements towards the enfranchisement of women since before the Roman era; it is all very well to point out that these movements are periodical, almost as inevitable as the volcanic eruptions that belch out their volumes of running fire and die down again into peaceful submission: but when the whole vital cause is altered, when the intrinsic motive in the entrails of that vast crater is changed, it is no wise policy to say, "It will pass over another two or three years and women will find, as they have always found before, that it is better to sit still and let others do the work."