Stones weighing from ten to twenty pounds were projected into the air, some of them crashing through the roof of the cabin when they descended. The mud and water grew into a pool, then a lake, completely surrounding the spot where the derrick had stood and where the geyser continued to spout. "We surely must move out," the oil man said, in much perturbation. "My shop yonder seems to be a target for those rocks. There goes another!" "And we have got to use a forge to weld and straighten these damaged rods!" Mark cried, worriedly. "Sorry, boy. I don't believe any of us will be able to get at my forge till this shower of missiles stops," said Phineas Roebach. "What needs to be done to the flying machine?" asked the professor, briskly. "Are you sure it can be repaired, Mark?" "Very sure, sir," replied the boy. "And you, Jack?" repeated Professor Henderson. "We could fix it up all right before midnight," declared the other. "But we must have a forge." "This geyser will stop playing after a bit, we will hope," said the professor, encouragingly. "If the flying machine is not past repair we need not worry. Nor need you, Mr. Roebach. We can all get away from this region if it becomes necessary." "Ma goodness!" gasped Washington White, who had listened to this speech with his mouth ajar. "Don't you consider, Perfesser, dat dere has erbout 'nuff happened yere fo' ter make it seem quite necessarious dat we evacuate de premises sorter promscuous an' soon like? Why, I done was sure de end ob He finish was at hand when dat las' big eart'quake hit us--I suah did!" "I must say I don't care to linger around here myself," muttered Andy. "We must not lose our courage," said the professor. "Never before have I been in a position to study seismic disturbances so closely. I only regret I have not with me here the instruments I brought in the _Snowbird_. And we must somehow learn the location of that volcano which is in eruption." "It's all right to learn the location of it," whispered Mark to Jack. "But if we learn that we'll be pretty sure to fly in the opposite direction--what do you think?" "Believe me," said Jack, "I've got enough. The old professor is all right, but he doesn't think about danger when his interest in any natural phenomena is aroused." The roaring of the geyser was a most unpleasant sound and the upheaval of the stones was more than unpleasant--it threatened danger to them. The vicinity of the oil-boring had been exceptionally free from small stones; but in half an hour one might have picked up a two-horse cartload weighing from ten to twenty pounds each.