"Now!"
The word came suddenly, and was followed by an almost imperceptible movement of the inventor's hand to a polished quadrant. A lever moved swiftly across the shining sector.
Almost instantly a shock made the submarine quiver. Tom knew that the tremendous forces that were to drive the bomb through the water had been released.
"Watch the wreck, please. If all goes well, you'll see something worth watching."
It was Mr. Ironsides speaking again. The faces of the visitors to the submarine were speedily glued against the observation lenses.
Tom saw a white streak cut through the water, leaving a train of bubbles in its wake. Then came a jar, and he felt a queer sensation on his ear drums, but that was all. All except that right ahead of them the black bulk of the wreck seemed suddenly to dissolve into nothingness. It had been and—was not!
Obadiah Ironsides' twentieth century revenge on the object that had so nearly caused disaster to his wonderful diving craft was complete.
"It's like magic!" gasped Tom, hardly able to believe that the solid timbers had been entirely obliterated before his very eyes.
"It is magic," breathed the professor.
"Now, I think we may as well arise and note the effects of our shot," said Mr. Ironsides, in his usual matter-of-fact voice. Now that the shot had been fired, and had been successful, the slight flush of anxiety on his pale face had vanished, leaving it as icicle-like as ever.