such as are used on most submarines, were put into gear.
They did well, but were not equal to the plates, nor was so
much expected of them.

"I am perfectly satisfied," announced Mr. Swift as he once
more headed the boat to sea. "I think, Captain Weston, you
had better go below now."

"Why so?"

"Because I am going to completely submerge the craft. Tom,
close the conning tower door. Perhaps you will come in here
with us, Captain Weston, though it will be rather a tight
fit."

"Thank you, I will. I want to see how it feels to be in a
pilot house under water."

Tom closed the water-tight door of the conning tower. Word
was sent through the tube to the engine-room that a more
severe test of the ship was about to be made. The craft was
now outside the line of breakers and in the open sea.

"Is everything ready, Tom?" asked his father in a quiet
voice.

"Everything," replied the lad nervously, for the
anticipation of being about to sink below the surface was
telling on them all, even on the calm, old sea captain.