An early supper was made on shore, as the professor said they might be so busy for the first few hours of the starting trip that they would get no chance to eat. Then the cabin and buildings where the submarine had been built, were securely fastened. "I guess we're all ready," announced the professor, taking a last look around. One by one they went aboard the _Porpoise_ crawling down through the man hole. The inventor was the last one to enter. He clamped the cover on by means of the cam levers and switched on the electric lights. Then he took his place in the conning tower with Andy Sudds. "Forward, to the South Pole!" exclaimed Mr. Henderson. With a turn of his wrist the inventor started the engines. The big screw in the shaft revolved, pulling the water in at one end of the craft and sending it out in a swirling stream at the other. The trip was fairly begun. For several miles the _Porpoise_ glided along on the surface of the ocean. It was a calm evening, and the boys down in the cabin of the craft could look into the reflecting mirrors on the wall, which were connected with observation magnifying glasses in the conning tower, and view what was going on, though their heads were below the surface of the sea. As it grew darker the view of shore and water faded away. The engine kept up its speed with Washington to see to it every now and then, oiling the bearings, some of which did not run quite smoothly because of their newness. "I'll send her down a bit now," observed the professor. "I don't want to run into any more warships or scare the crews by making them think we are a foreign torpedo boat." He opened the sea cocks in the ballast tanks and soon the _Porpoise_ sunk about two hundred feet beneath the waves. The craft, which had been pitching and tossing under the influence of a ground swell, became more steady and quiet once it left the surface. The searchlight in the conning tower was turned on, and in the glare of it Andy and the professor were able to steer properly, aided by the compass which gave them the true southern course. It was now quite dark. Additional electric lights were switched on in the cabin, engine and dining room. Andy came out of the conning tower and announced that Captain Henderson wanted Washington to get supper. All the cooking was done by electricity, and, in addition to a supply of the usual and ordinary kinds of food, there was a big lot of patent condensed victuals to draw on. Soup, broiled steak, potatoes, hot biscuits, rice pudding and coffee made up the repast which was enjoyed by all. Toward the close of the meal Professor Henderson began to sniff the air of the cabin. "What's the matter? Do you smell a storm brewing?" asked Andy. "No, but the air is not as fresh as it should be," replied the inventor. "Washington, release a little more of the supply from the compression tanks."