So Jack gave the speed wheel a small turn, then rested both hands on the steering wheel. Without an unnecessary sound, and with no outer lights showing, as yet, the "Pollard" was headed for the mouth of the little harbor, Mr. Farnum standing by as pilot.
Just as they passed out on to the edge of the ocean Farnum himself turned on the electric sailing lights.
"She rides the water easily," remarked Pollard, almost in a whisper. "I wonder how she can go at speed?"
"We'll find out, now we've got clear seaway ahead," replied Mr. Farnum.
"Benson, turn on a few miles more."
Quickly obeying the impulse of her twin-propellers, the "Pollard." began to dance over the waves.
"Say, but she's the fine, light-riding boat!" cried the builder, joyously.
"Just as I thought she would be. Give her more speed, Benson."
So the speed was turned on, more and more. The "Pollard," as far as those aboard, could see, had the whole of that part of the ocean to herself. She was still headed due east, and was moving at last at the rate of seventeen of the twenty-one miles an hour of which she was believed to be capable.
Even at this rapid gait the semi-immersed "Pollard" rode splendidly, with hardly any vibration noticeable.
As he watched, instead of feeling the thrill of triumph that influenced the crew, David Pollard's face was whitening with anxiety. His face, almost ghastly in its look, was deeply furrowed.
"We're doing well enough on top of the water," he muttered, hoarsely, at last, to the builder. "But will the boat dive? How will she run under water? I must—know!"