Sometimes these fires burst forth from the crater of the volcano with tremendous force. The smoke becomes thick and black, and lurid flames shoot up to a height of hundreds of feet, making a scene of amazing grandeur.
With the flames there are thrown out stones, ashes, and streams of melted rock, called lava. This lava flows down the sides of the mountain, and, being red-hot, destroys every thing with which it comes in contact. At such times, a volcano is said to be in eruption.
A volcanic eruption is generally preceded by low, rumbling sounds, and trembling of the earth's surface. Then follows greater activity of the volcano, from which dense volumes of smoke and steam issue, and fire and molten lava make their appearance.
Such is the force of some of these eruptions, that large rocks have been hurled to great distances from the crater, and towns and cities have been buried under a vast covering of ashes and lava.
The quantity of lava and ashes which sometimes escapes from volcanoes during an eruption, is almost beyond comprehension.
In 1772, a volcano in the island of Java, threw out ashes and cinders that covered the ground fifty feet deep, for a distance of seven miles all around the mountain. This eruption destroyed nearly forty towns and villages.
In 1783, a volcano in Iceland sent out two streams of lava; one forty miles long and seven miles wide, and the other fifty miles long and fifteen miles wide. These streams were from one hundred to six hundred feet deep.
Near the city of Naples, Italy, is situated the volcano Mt. Vesuvius. This fiery monster has probably caused more destruction than any other volcano known.
In the year 79 A.D., it suddenly burst forth in a violent eruption, that resulted in one of the most appalling disasters that ever happened.