At this moment an awful crash was heard. It came from the building containing the automatic shell. Clewe and Margaret started to their feet. They glanced at each other, and then both ran from the office at the top of their speed. Other people were running from various parts of the Works. There was no smoke; there was no dust. There had been no explosion, as Clewe had feared in his first alarm. When they entered the building, Clewe and Margaret stood aghast. There were workmen shouting or standing with open mouths; others were running in. The massive scaffolding, twenty feet in height, on which the shell had been raised so that the steel trough might be run under it, lay in splinters upon the ground. The great automatic shell itself had entirely disappeared. For some moments no one said anything; all stood astounded, looking at the space where the shell had been. Then Clewe hurried forward. In the ground, amid the wreck of the scaffolding, was a circular hole about four feet in diameter. Clasping the hand of a man near him, he cautiously peered over the edge and looked down. It was dark and deep; he saw nothing. Roland Clewe stepped back; he put his hands over his eyes and thought. Now he comprehended everything clearly. The weight of the shell had been too great for its supports. The forward part, which contained the propelling mechanism, was much heavier than the other end, and had gone down first, so that the shell had turned over and had fallen perpendicularly, striking the ground with the point of the cone. Then its tremendous propelling energy, infinitely more powerful than any dynamic force dreamed of in the preceding century, was instantly generated. The inconceivably rapid motion which forced it forward like a screw must have then commenced, and it had bored itself down deep into the solid earth. “Roland, dear,” said Margaret, stepping quietly up to him, tears on her pale countenance, “don't you think it can be hoisted up again?” “I hope not,” said he. “Why do you say that?” she asked, astonished. “Because,” he answered, “if it has not penetrated far enough into the earth to make it utterly out of our power to get it again, the thing is a failure.” “More than that,” thought Margaret; “if it has gone down entirely out of our reach, the thing is a failure all the same, for I don't believe he can ever be induced to make another.” CHAPTER XVI. THE TRACK OF THE SHELL During the course of his inventive life Roland Clewe had become accustomed to disappointments; he was very much afraid, indeed, that he was beginning to expect them. If that really happened, there would be an end to his career. But when he spoke in this way to Margaret, she almost scolded him. “How utterly absurd it is,” she said, “for a man who has just discovered the north pole to sit down in an arm-chair and talk in that way!” “I didn't discover it,” he said; “it was Sammy and Gibbs who found the pole. As for me--I don't suppose I shall ever see it.”