All British war vessels were equipped with anti-aircraft guns and these were ever loaded and ready for action; for there was no telling what moment they might be called into use to repel a foe. Upon several occasions attacks of the Zeppelins had been beaten off with these guns, though, up to date, none had been brought down. But now there had been perfected a new anti-aircraft gun. With this it was believed that the battleship stood a good chance of bringing down a Zeppelin should it venture near enough. With such a gun the _Queen Mary_ had been equipped as she was overhauled in dry dock. With this gun went four men. One to stand by the gun at night and keep watch of the sky and a second to do duty in the day time. The other two men stood relief watches and were of additional need should one of the first men be injured, taken sick or killed. And so it was that, as the _Queen Mary_ continued on her way, one of these men stood by his gun just aft of the bridge, watching the sky. Nor did he shirk his task. Almost continuously his eye swept the dark heavens, following, as well as he could, in the path of one or the other of the searchlights. He used powerful night glasses for this purpose. Suddenly he gave a start. He looked closely again through his glasses. Then he uttered a cry of alarm. The third officer, on the bridge, gave an exclamation. "What do you see?" he demanded. "Zeppelin," was the reply. "Douse the light aft. Have the man forward see if he can pick up the craft with his flash. About two points east by north." There came sharp commands aboard the _Queen Mary._ CHAPTER III WARSHIP AND ZEPPELIN A bell tinkled in the engine room of the _Queen Mary_. The ship slowed down. Captain Raleigh had been called by the third officer. He took the bridge and issued his orders sharply. There was no telling whether the Zeppelin sighted by the man at the gun would attack the ship, but Captain Raleigh considered it best to be on the safe side. That was why he had left orders to be called immediately should an enemy appear. Again a bell tinkled in the engine room, following an order from the commander of the _Queen Mary_. The great engines stopped and became silent. "Cut off all lights!" was the next command. A moment later the great ship was in darkness. Frank and Jack, in their quarters, were awakened by the sounds of confusion above. All hands had not been piped on deck, so most of the men still lay asleep, unconscious of what was going on above, but the two lads, dressing hurriedly, made their way on deck. They walked forward, toward the bridge. All was dark and it was this that told Frank and Jack that something was going on. "Wonder what's up?" said Frank. "Airship, I guess," was the reply. "Can't see any other reason for extinguishing all lights."