ELECTRIC PHENOMENA

Among the stones tossed out of the craters was one large mass of pumice weighing nearly half a ton, which was carried to a distance of between four and five miles.  The rivers were flooded by the melting of ice and snow which had accumulated on the mountain.  The greatest mischief wrought by these successive eruptions was the destruction of the pasturages, which were for the most part covered with volcanic ashes.  Even where left exposed, the herbage acquired a poisonous taint which proved fatal to the cattle, inducing among them a peculiar murrain.  Fortunately, owing to the nature of the district through which the lava passed, there was on this occasion no loss of human life.

The Icelandic volcanoes are remarkable for the electric phenomena which they produce in the atmosphere.  Violent thunder-storms, with showers of rain and hail, are frequent accompaniments of volcanic eruptions everywhere; but owing to the coldness and dryness of the air into which the vapors from the Icelandic volcanoes ascend, their condensation is so sudden and violent that great quantities of electricity are developed.  Thunder-storms accompanied by the most vivid lightnings are the result.  Humboldt mentions in his “Cosmos” that, during an eruption of Kotlugja, one of the southern Icelandic volcanoes, the lightning from the cloud of volcanic vapor killed eleven horses and two men (Cosmos i. 223).  Great displays of the aurora borealis usually accompany the volcanic eruptions of this island—­doubtless resulting from the quantity of electricity imparted to the higher atmosphere by the condensation of the ascending vapors.  On the 18th of August, 1783, while the great eruption of Skaptar Jokull was in progress, an immense fire-ball passed over England and the European continent as far as Rome.  This ball which was estimated to have had a diameter exceeding half a mile, is supposed to have been of electrical origin, and due to the high state of electric tension in the atmosphere over Iceland at that time.

CHAPTER XXIV.

Volcanoes of the Philippines and Other Pacific Islands.

We cannot do better than open this chapter with an account of the work of volcanoes in the mountain-girdled East Indian island of Java.  This large and fertile tropical island has a large native population, and many European settlers are employed in cultivating spices, coffee and woods.  The island is rather more than 600 miles long, and it is not 150 miles broad in any part; and this narrow shape is produced by a chain of volcanoes which runs along it.  There is scarcely any other region in the world where volcanoes are so numerous, even in the East, where the volcano is a very common product of nature.  Some of the volcanoes of Java are constantly in eruption, while others are inactive.