The cooking was all done by this useful current, and all that was necessary to make a cup of coffee or fry a beefsteak was to turn a small switch of the electric stove. The professor was busy over the machine for generating gas, that furnished the heat to create steam. Soon a hissing told that it was working. In a few minutes the hum and throb of the engine told that it was ready to start. "We are only going down a little way," the professor said, "and only going to travel a short distance under water for the first time. I think there is no danger, but if any of you want to back out, now is your chance." No one seemed inclined to withdraw, though Mark said afterward he thought Washington got as pale as it is possible for a colored man to get. "We will all put on life preservers," the inventor went on, "and one of you will be stationed near the emergency exit. In case anything goes wrong, and I cannot make the ship rise, by pulling the lever the top of the craft will be forced off, and, we can at least save our lives. I think we are all ready now. Mark, you clamp down the manhole cover, and Jack, after you close the conning tower station yourself at the emergency lever after we have donned the life preservers." The cork jackets were adjusted and Mark clamped the manhole cover on. The professor took one last look at the various levers and handles, and then turned the wheel that admitted water to all four tanks. There was a hissing sound as the sea water rushed in, and the _Porpoise_ gave a sudden lurch. Then they could all feel the submarine sinking. Down and down she went. Would she ever stop? Would the professor be able to raise her again? There were questions that troubled everyone. Down and down the craft sunk, until by the gage it was indicated that she was twenty feet below the surface. Then the professor shut off the inrush of water and the _Porpoise_ floated away below the surface of the waves. There was a clicking sound and all the lights went out. The boys and Washington gave a gasp of terror. What did the sudden blackness mean. "Open the side windows," called the professor's voice, and the two machinists obeyed. Heavy steel doors that covered plate glass windows in either side of the craft were pulled back, and a cry of astonishment broke from the boys. They looked out and saw staring in at them, so close it seemed that they could touch them, scores of fishes that looked in through the glass bull's-eyes. For the first time they realized that they were in the depths of the ocean. CHAPTER III RUNNING DOWN A WARSHIP "How do you like it?" asked the professor. "Great!" exclaimed Jack. "Fine!" cried Mark. "It am simply coslostrousness!" exploded Washington. "'Nebber in all my born days did I eber expansionate on such a sight!" "Wish I had a fishing pole and line," remarked Andy Sudds. "There's some pretty nice specimens out there."