Chapter Nineteen. Captured

"Down deep," advised Captain Weston, as he stood beside Tom and Mr. Swift in the pilot house. "As far as you can manage her, and then forward. We'll take no more chances with these fellows."

"The only trouble is," replied the young inventor, "that the deeper we go the slower we have to travel. The water is so dense that it holds us back."

"Well, there is no special need of hurrying now," went on the sailor. "No one is following you, and two or three days difference in reaching the wreck will not amount to anything."

"Unless they repair their rudder, and take after us again," suggested Mr. Swift.

"They're not very likely to do that," was the captain's opinion. "It was more by luck than good management that they picked us up before. Now, having to delay, as they will, to repair their steering gear, while we can go as deep as we please and speed ahead, it is practically impossible for them to catch up to us. No, I think we have nothing to fear from them."

But though danger from Berg and his crowd was somewhat remote, perils of another sort were hovering around the treasure-seekers, and they were soon to experience them.

It was much different from sailing along in the airship, Tom thought, for there was no blue sky and fleecy clouds to see, and they could not look down and observe, far below them, cities and villages. Nor could they breathe the bracing atmosphere of the upper regions.

But if there was lack of the rarefied air of the clouds, there was no lack of fresh atmosphere. The big tanks carried a large supply, and whenever more was needed the oxygen machine would supply it.

As there was no need, however, of remaining under water for any great stretch of time, it was their practice to rise every day and renew the air supply, also to float along on the surface for a while, or speed along, with only the conning tower out, in order to afford a view, and to enable Captain Weston to take observations. But care was always exercised to make sure no ships were in sight when emerging on the surface, for the gold-seekers did not want to be hailed and questioned by inquisitive persons.

It was about four days after the disabling of the rival submarine, and the Advance was speeding along about a mile and a half under water. Tom was in the pilot house with Captain Weston, Mr. Damon was at his favorite pastime of looking out of the glass side windows into the ocean and its wonders, and Mr. Swift and the balloonists were, as usual, in the engine-room.

"How near do you calculate we are to the sunken wreck?" asked Tom of his companion.

"Well, at the calculation we made yesterday, we are within about a thousand miles of it now. We ought to reach it in about four more days, if we don't have any accidents."

"And how deep