Progress under the water was comparatively slow, as mankind had made but little progress in underwater navigation. Air liners long before had almost superseded travel by land and sea and the abolition of warfare had swept all of the old navies from the ocean. It was more than an hour before the officer in charge of the boat announced that the mammoth hull of the monster that was lying on the Sound was visible directly above them. Both Dirk and Steinholt donned diving apparatus, and the former carefully adjusted the mechanism that was contained in a metallic box about two feet square. * * * * * Then they stepped up into a chamber in the conning tower of the boat and, after a door slipped shut beneath them, water slowly commenced to pour into the compartment. When it was full a sliding door that was in front of them slowly opened and they passed out onto the deck of the underwater craft. Steinholt had been provided with some welding apparatus and, in a few minutes, the box which Dirk had carried was attached securely to the bottom of the craft of the Lodorians. They then reentered the submarine by reversing the process which had attended their exit. Very soon they were in the cabin of the boat again. "If everything goes well," said Dirk, "those damned Lodorians will never know what struck them." "I only hope," said Steinholt, "that we don't destroy that leviathan altogether. We might solve the secret of it and then we, too, could ride out into the heart of the universe." "It is impossible to imagine what will happen," Dirk replied, "until after we launch our attack." Both of the men were silent during the return trip of the small undersea craft, which emerged at its dock a little before three-thirty in the morning. "We'll have to hurry," urged Dirk nervously, "because we will need a little time to make preparations after we get back to Fragoni's." They entered their plane and Dirk shot it swiftly up into the night, following the red shaft of light that rose almost directly from the point at which they had made their landing. * * * * * Then, having reached the eastbound level, he headed straight in the direction of the palace of Fragoni. Dirk cast a glance at the great city that lay far beneath him. High up into the heavens it tossed the fulgurant fires that betokened its wealth and power. And, down among those myriad lights, millions and millions of people were restless under the danger that menaced them. It was only a matter of moments now before their fate, and the fate of their great metropolis, would be decided. By dawn they would be free forever from the threat of subjugation and slavery or else they, and all that they had toiled and striven for, would be the veriest dust of dying embers. And whatever befell them likewise would befall the rest of the world and every living thing that moved upon it.