"You'll see better ones than those before we finish our trip to the pole," remarked the professor. "Now we will try moving forward. I am going into the conning tower."
He turned on the lights once more, but the boys begged him to shut them off, as they could see out into the ocean when the interior of the ship was in darkness. So the professor obliged them.
In the tower he switched on the powerful searchlight that illuminated the path in front of him. Then he started the engine, slowly at first, and gradually increasing the speed. The Porpoise forged ahead, riding as evenly as an ordinary ship does on the surface.
The professor steered her about in a large circle, bringing her back to the starting point. She worked as smoothly as if she had been used to under-water service for years.
"Now," said the inventor, "we will see if we can go up to the surface again," and there came a little note of anxiety into his voice. He slowed down the engine and started the powerful pumps that were to empty the tanks. For a moment there was a feeling of terror in the hearts of all. Would the pumps work?
Then, slowly but surely, those aboard the Porpoise felt her beginning to rise. Up and up she went as the tanks were emptied and the ship lightened.
Then, with a bounce like a rubber ball, the submarine shot upward to the surface and lay undulating on the waves caused by her emergence from the depths.
"Hurrah!" shouted Jack. "We're all right!"
"We shore am!" exclaimed Washington.
"It's a success!" Professor Henderson almost whispered. "The pumps worked. The Porpoise has fulfilled my greatest expectations!"