“I think I’ve got an idea,” he said; “of course, although it looks all right on paper, it might not work out in practice.”
“Let’s see it, my boy,” said Mr. Chadwick.
The rough sketch that Jack had made showed the White Shark equipped with peculiar looking paddle-wheels of spiral design instead of the ordinary type.
“My idea is,” he said modestly, “that of the Archimedian screw. When on the surface these spirals could be set level, but a slight tilt would drive the White Shark down toward the bed of the sea. To rise, you would simply have to reverse the process.”
Mr. Chadwick nodded thoughtfully.
“Your idea sounds by no means impossible of being put into practice,” he said after a moment’s consideration and a swift scrutiny of Jack’s rough sketch.
“We would have to test it out with a model, of course,” said Tom.
“Of course. But the engines in the White Shark are not so placed that they would drive propellers of this character, for, you know, there would be one on each side, on the principle of paddles instead of stern propellers.”
“That was my idea,” said Jack; “but I think it would be a simple matter to alter the position of the motors and install all the necessary driving shafts and gears.”
The subject was discussed till late and they parted for the night determined to put Jack’s idea to a test in the morning. There was much apparatus of various character about the workshops attached to High Towers, and they anticipated that the work of constructing a rough model would not take long. As readers of the other volumes of this series know, High Towers was a big estate embracing a lake and surrounded by a high fence, insuring privacy.