"Not so far as I know. Have a plan to catch him red-handed. You watch the motor-boat."
Saluted by the whistles of a hundred water craft, the Columbia made stately progress into Southampton harbor. As her leviathan bulk moved majestically along under reduced speed, her whistles blowing and her flag dipping in acknowledgment of the greeting, Jack with a beating heart, stood on the upper deck watching earnestly for developments.
He knew that Billy and the two firemen he had selected to help him, on what might prove a dangerous job, were below watching Prof. Dusenberry. They all wore stewards' uniforms so that the man who Jack believed struck down the diamond merchant and stole the stones might not get suspicious at seeing them about in the corridors.
"I believe they must have changed their plans, after all," Jack was thinking when, from the shore, there shot out, at tremendous speed, a sharp-bowed, swift motor-boat. It headed straight for the Columbia. As it drew closer, Jack saw it held two men. Both were blowing a whistle, waving flags and pointing at the big ship as if they, like many other small water craft, were just out to get a glimpse of the triumph of American shipbuilders.
They maneuvered close alongside, while Jack's fingers grasped the rail till the paint flaked off under the pressure he exerted in his excitement. What was happening below? he wondered. Could Billy and his companions carry out their part of the program? Not far from the boy the diamond merchant, unconscious of the drama being enacted on his account, stood, with bandaged head, explaining for the hundredth time the beauty and the value of the gems he had lost.
"Five thousand thalers I give if I get them back," he declared.
Suddenly Jack's heart gave a bound. From a port far down on the side of the ship, and almost directly under him, a white object was hurled. It struck the water with a splash and spread out, floating buoyantly.
Instantly the black motor-boat darted forward, one of the men on board holding a boat hook extended to grasp the floating life-preserver, hidden in which was a king's fortune in gems.
Jack stood still just one instant. Then, driven by an impulse he could not explain, he threw off his coat, kicked off the loose slippers he wore when at work, and the next moment he had mounted the rail and made a clean, swift dive for the life-preserver.
Billy rushed on deck, excitement written on his face, just as Jack dived overboard.