At the very instant the lad disappeared beneath the water there was a flash of fire above the submarine, followed by a violent explosion-fearful, terrific.
The upper work of X-9 was blown high into the air and came down in splinters, scattered to the four winds of heaven. The deck was rent and open up with a great, yawning scam, through which the ocean rushed, driving the craft below the waves as though it had been drawn down by some mighty whirlpool. A minute later, where had been one of Germany's most terrible fighters, there was only a seething flood of water covered with floating wreckage.
The force of the explosion sent the water spouting high in the air like giant gushers. The sea boiled and lashed out angrily at what was left of the German craft. Not a living figure was to be seen upon the wreckage.
The deadly melinite had done its work.
Beneath the waters of the North Sea, where Frank and Jack had sought what shelter they could, the water tossed them about at will, in spite of their frantic efforts to hold themselves steady and remain below the surface.
Frank, not having time to take such a long breath as Jack, because of the suddenness with which he had dived, was the first to come to the surface. He was tossed high on the still angry waves, but by a Herculean effort, the lad managed to keep his head above water.
His first thought was of the small boat he had so recently left. Glancing around, he saw it floating, bottom up, about a hundred yards away. He swam rapidly toward it; and as he hurried along, a head suddenly bobbed up directly in front of him.
It was Jack, struggling and gasping. Frank swam rapidly to him, and lent what assistance he could. Soon Jack was swimming easily with his friend toward the little upturned boat.
They laid hold of the little craft, and after a struggle, succeeded in righting it and clambering aboard, where they sat down, wet and weak, Then, for the first time, Jack turned his eyes toward the spot where so short a time ago had been the German submarine. He saw the mass of floating wreckage.
"Gone," he said simply, "and the poor fellows with it." He turned to Frank. "You certainly did a good job. I never knew that you were so handy with a gun."