Just then Mark happened to look at the bull's-eye. He saw a glimmer of light. Then he noticed several fishes swimming about. The water was clear. The grass had disappeared from the vicinity of the window.
"Look!" cried Mark to the professor.
The inventor peered forth. As he did so he uttered a cry. Then he staggered rather than ran to the engine room.
"What are you doing?" he called to Washington.
"I jest let some ob de sulphuric acid out ob de storage battery tank," replied the colored man.
"That's it! That's it!" exclaimed the professor. "Quick, let some more out, Washington. Let out all there is in that tank. It will save our lives."
Wonderingly Washington obeyed. The air in the ship was growing more foul every second. It was hard to breathe even on the floor, and all were gasping for breath. A few minutes more and they would all become unconscious and death would come in a little while if the air was not freshened.
The professor staggered back to the main cabin. He looked out of the bull's-eye windows. Then he exclaimed:
"See, it is getting lighter! Thank Heaven we are saved!"
The next instant the ship began to move backward. Then with increasing speed it pulled out of the grip of the long grass, and in another minute was floating on top of the water, at the edge of the Sargasso Sea.