The Story Book of Science  by Jean Henri Fabre


"Y ESTERDAY," Uncle Paul resumed, "Jules asked me if the lava-streams could not reach towns situated near volcanoes. The following story will answer his question. It is about an eruption of Mount Etna."

"Etna is that volcano in Sicily where the big chestnut tree of a hundred horses is?" asked Claire.

"Yes. I must tell you that two hundred years ago there occurred in Sicily one of the most terrible eruptions on record. During the night, after a furious storm, the earth began to tremble so violently that a great many houses fell. Trees swayed like reeds shaken by the wind; people, fleeing distracted into the country to avoid being crushed under the ruins of their buildings, lost their footing on the quaking ground, stumbled, and fell. At that moment Etna burst in a fissure four leagues long, and along this fissure rose a number of volcanic mouths, vomiting, amid the crash of frightful detonations, clouds of black smoke and calcined sand. Soon seven of these mouths united in an abyss that for four months did not cease thundering, glowing, and throwing up cinders and lava. The crater of Etna, at first quite at rest, as if its furnaces had no connection with the new volcanic mouths, woke up a few days after and threw to a prodigious height a column of flames and smoke; then the whole mountain shook, and all the crests that dominated its crater fell into the depths of the volcano. The next day four mountaineers dared to climb to the top of Etna. They found the crater very much enlarged by the falling-in of the day before: its orifice, which before had measured one league, now measured two.

"In the meantime, torrents of lava were pouring from all the crevasses of the mountain down upon the plain, destroying houses, forests, and crops. Some leagues from the volcano, on the seacoast, lies Catania, a large town surrounded then by strong walls. Already the liquid fire had devoured several villages, when the stream reached the walls of Catania and spread over the country. There, as if to show its strength to the terrified Catanians, it tore a hill away and transported it some distance; it lifted in one mass a field planted with vines and let it float for some time, until the green was reduced to charcoal and disappeared. Finally, the fiery stream reached a wide and deep valley. The Catanians believed themselves saved: no doubt the volcano would exhaust its strength by the time it covered the vast basin which the lava had just entered. But what an error of judgment! In the short space of six hours, the valley was filled, and the lava, overflowing, advanced straight toward the town in a stream half a league wide and ten meters high. It would have been all over with Catania if, by the luckiest chance, another current, whose direction crossed the first, had not come and struck against the fiery flood and turned it from its course. The stream, thus turned, coasted the ramparts of the town within pistol-shot, and turned toward the sea."

"I was very much afraid for those poor Catanians," interposed Emile, "when you spoke of that wall of fire, high as a house, going straight toward the town."

"All is not over yet," his uncle proceeded. "The stream, I told you, was going toward the sea. There was, then, a formidable battle between the water and the fire. The lava presented a perpendicular front of 1500 meters in extent and a dozen meters high. At the touch of that burning wall, which continued plunging further and further into the waves, enormous masses of vapor rose with horrible hissings, darkened the sky with their thick clouds, and fell in a salt rain over all the region. In a few days the lava had made the limits of the shore recede three hundred meters.

"In spite of that, Catania was still menaced. The stream, swollen with new tributaries, grew from day to day and approached the town. From the top of the walls the inhabitants followed with terror the implacable progress of the scourge. The lava finally reached the ramparts. The fiery flood rose slowly, but it rose ceaselessly; from hour to hour it was found to have risen a little higher. It touched the top of the walls, whereupon, yielding to the pressure, they were overthrown for the length of forty meters, and the stream of fire penetrated the town."

"My goodness!" cried Claire. "Those poor people are lost!"

"No, not the people, for lava runs very slowly, on account of its sticky nature, and one can be warned in time; it was the town itself that ran the greatest risk. The quarters invaded by the lava were the highest; from there the current could spread everywhere. So Catania seemed destined to total destruction, when it was saved by the courage of some men who attempted to battle with the volcano. They bethought themselves to construct stone walls, which, placed across the route of the on-coming stream, would change its direction. This device partly succeeded, but the following was the most efficacious. Lava streams envelop themselves in a kind of solid sheath, embank themselves in a canal formed of blocks coagulated and welded together. Under this covering the melted matter preserves its fluidity and continues its ravaging course. They thought, then, that by breaking these natural dikes at a well-chosen spot, they would open to the lava a new route across country and would thus turn it from the town. Followed by a hundred alert and vigorous men, they attacked the stream, not far from the volcano, with blows of iron bars. The heat was so great that each worker could strike only two or three blows in succession, after which he withdrew to recover his breath. However, they managed to make a breach in the solid sheath, when, as they had foreseen, the lava flowed through this opening. Catania was saved, not without great loss, for already the lava flood had consumed, within the town walls, three hundred houses and some palaces and churches. Outside of Catania, this eruption, so sadly celebrated, covered from five to six square leagues with a bed of lava in some places thirteen meters thick, and destroyed the homes of twenty-seven thousand persons."

"Without those brave men who did not hesitate, at the risk of being burnt alive, to go and open a new passage for the stream of fire, Catania would certainly have been lost," remarked Jules.

"Catania would have been all burnt down, there is no doubt. To-day its calcined ruins would be buried under a bed of cold lava, and there would be nothing left but the name of the large town that had disappeared. Three or four stout-hearted men revive the courage of the terrified population; they hope that heaven will aid them in their devotion, and, ready to sacrifice their lives, they prevent the frightful disaster. Ah! may God give you grace, my dear child, to imitate them in the time of danger; for, you see, if man is great through his intelligence, he is still greater through his heart. In my old age, when I hear you spoken of, I shall be more gladdened by the good you may have done than by the knowledge you may have acquired. Knowledge, my little friend, is only a better means of aiding others. Remember that well, and when you are a man bear yourself in danger as did those of Catania. I ask it of you in return for my love and my stories."

Jules furtively wiped away a tear. His uncle perceived that he had sown his word in good ground.