Very shortly the lighthouse that stood on the cape's end marking the harbor entrance had been passed and the _Dewey_ was out on the open sea. Before the boys stretched water---endless water as far as the eye carried---to the far thin line where sky and water met. They were lost in contemplation of the wonderful view. But their reveries were suddenly disturbed by a sharp command from Executive Officer Binns: "All hands below---we are going to submerge!" The _Dewey_ was going to dive! CHAPTER III SEALED ORDERS Ted and Jack hastened to follow their comrades down the hatchway. A sea-gull flapping by squawked shrilly at them as the boys waited their turn at the ladder. Instinctively they took another look around them before dipping into the hold of the _Dewey_. They realized that here, indeed, was the real thrill of submarining. The cap was lowered at last and secured, and the crew hastened to their posts amid the artificial light and busy hum of the ship's interior. Now the Brighton boys were to learn how the _Dewey_ was to be submerged! For one thing they noted that the oil engines used for surface cruising were shut off and the locomotion of the vessel switched over to the electric drive of the storage batteries. But their attention was directed chiefly to Navigating Officer Binns, who had taken up his position before a row of levers and water gauges amidships. "Pump three hundred pounds into No. 1," was the command given by Binns. One of the levers was thrown over, and immediately could be heard the swirling of water. The boys were unable to grasp the full meaning of what was going on until Bill Witt shuffled up and said: "I'll put you fellows wise to what's going on, if you want me to." Ted and Jack were glad to know what it was all about and listened attentively to the commands of the navigating officer and the interpretations given by their new-found friend. Bill explained that the process of diving was called "trimming" in submarine cruising, and that the pumping of the water being directed by Binns was done to fill the ballast tanks, thus increasing the displacement of the _Dewey_ and causing it to settle in the water. First one tank was filled, and then another, until the vessel was submerged on an even keel. This was a revelation to the boys, for they had supposed it was only necessary to tilt the ship and dive just like a porpoise. To their great delight the recruits found that the _Dewey_, like other submarines built since the beginning of the great world war, was equipped with twin periscopes, and that, furthermore, they would be allowed to watch the submersion of the _Dewey_ through the reserve periscope if they so desired. Would they care to? Well, rather! For the next few minutes they took turn about peering into the mirrors that reflected the whole panorama before their eyes.