But these were only subsidiary uses of the tappings of the central earth fires. Their main and original purpose was to relieve the perturbations of Lilaroma. It was one of the chief duties of the Leomo to watch over the destiny of their island, which was volcanic in its origin, though it had been greatly added to in former ages by the coral insect. Lava-streams had overspread the coral, and then the myriads of minute architects had thrust out their structures farther and farther into the sea and thus the lowlands had been broadly extended, while the red-hot layers of lava added massiveness to the body of the island. Yet it was continually shaken by earthquakes and threatened with partial if not complete disaster. It was the function of Leomarie to watch the approach of these earthquakes and guard against them. The Leomo had the most delicate instruments for recording every tremor of the earth’s crust. They had also thermometers and electrometers down their heat wells and lava wells, and these automatically recorded at the surface every variation of the heat and magnetism of the earth. They had classified through many centuries all the preliminary and concomitant circumstances of earthquakes, and had found and formulated certain causal relations amongst them. Thus the minutest symptom of change in the records made by their instruments roused them to watchfulness. They were soon able to tell in what direction the explosive materials were accumulating and how far below the surface of the earth; then, when they had fixed with more or less definiteness the time they had to spare, they began sinking lava wells right into the perturbed lake of fire. The vent acted as safety-valve; the shakings of the island ceased as the steam roared forth, and the molten rock began to yeast down the side of the mountain. All danger was past for another period of time. Again and again throughout the past ages the Leomo had saved the island from the ravages of earthquake and uncontrolled lava-streams from the crater of Lilaroma. Never did they intermit their vigilance or cease to advance their knowledge of the earth and its habits and laws. It seemed to me at first that nothing could occur in the crust of our planet which they would not foresee. I came afterwards to know the limits of Leomarie, and the reasons why they pushed almost feverishly forward to further knowledge. They were ever afraid that something unforeseen might occur and threaten the stability of their land and the progress towards the nobler life.