There was plenty of shipping to carry an army far larger than the federated governments could mobilize; the main weakness of the expedition lay in the lack of naval protection, for the great navies of the world had perished when the northern hemisphere passed under the influence of the comet. It was sought to make up for this deficiency by a vast cloud of airplanes, flying from the decks of many merchant ships, converted into aircraft carriers, though some of the new rocket-planes were powerful enough to cruise around the world under their own power. And so, on this March morning in 1947 the whole vast armada was crossing the Atlantic toward the United States. In view of the fact that the headquarters of the dodos seemed to be somewhere in the Catskills, it had been decided to land in New Jersey, form a base there and work northward. In the preliminary training for the coming conflict the metal Americans had played an important part. Their construction made them impossible as aviators, which they would have preferred. But quite early it was discovered that they made ideal operators for tanks. The oil fumes and the lack of air did not in the least affect beings to whom breathing had become unimportant, and the oil was actually a benefit. As a result the little American army had been composed of fourteen tanks of a special type, fitted at the direction of the military experts, with all the latest and best in scientific devices. They were given extra-heavy armor, fitted in two thicknesses, with a chamber between, as a protection against the light-bombs, and each tank, intended to be handled by a single operator, was provided with one heavy gun, so arranged that it could be used against aerial attack. * * * * * A stir of motion was visible at the head of the convoy. A destroyer dashed past the _Paramatta_, smoke pouring from her funnels, the white bow-wave rising as high as her bridge as she put on full speed. From the airplane carrier just behind them in the line, one, two, three flights of fighters swung off, circled a moment to gain altitude and then whirled off to the north and west. "What is it?" asked Gloria. A sailor touched his cap. "Sighted a dodo, I believe, miss," he said. "Oh, boy," said Gloria, "here we go. What would you give to be in one of those planes?" They craned their necks eagerly, but nothing was visible except a few flecks in the sky that might be dodos or might equally well be airplanes. Faint and far, a rattle of machine-guns drifted down; there was a flash of intense light, like the reflection in a far-distant mirror, and the machine-guns ceased. A few moments later the airplanes came winging back to their mother ship. A sailor on her deck began to swing his arms in the curious semaphore language of the sea. "What happened?" asked Gloria of the man by their side.