"Not this time," replied the professor. "You had a close call, though. How did it happen?"

Washington explained that he started to clean the battery tank, when he lost his balance and fell in. He cried as he felt himself falling, but as soon as he struck the bottom of the tank the fumes of the chemicals made him unconscious. His deep breathing, which had sounded like groans, alone served to attract attention to his location.

In a little while Washington was all right save for a slight weakness. Captain Henderson made him go to his bunk, and ordered him to remain there until morning.

During the excitement over Washington's mishap all thought of steering the ship had been forgotten, and when Mr. Henderson went to the conning tower about five o'clock he found that the Porpoise was several points off her course and was headed to the east instead of to the south. How many miles out of her way the craft had steamed could only be guessed, but as she had been going wrong for nearly an hour, it must be quite a few the inventor calculated.

However, he said, no great harm had been done. Even this slight accident would not have happened had not Bill, who was in the conning tower steering, forgotten to put the automatic device in operation when he left the wheel to join in the search for Washington.

"We'll soon make up the lost ground," said Mr. Henderson. "Another week or ten days ought to see us at the end of our journey."

"And what will we do when we get there?" asked Jack.

"We will make some important geographical and scientific observations," said the professor. "Not only that, but we will have done something that no living person has ever accomplished. We reached the north pole, though we could not land on the exact spot. Let us hope we will be more successful regarding the south pole."

The professor set the ship on her course again. Bill and Tom got supper in place of Washington, while Mrs. Johnson helped set the table.

The meal was eaten, and then the inventor started the ship toward the surface, following the plan of not sailing beneath the waves after dark, in order to avoid accidents.