“You forget the stowaway, sir,” said Frank.
“But there is no stowaway.”
“There must be a stowaway! How else do you account for this? The vessel could not do it by itself.”
There was still a perceptible motion of the vessel.
“We’re rising,” cried Jack in alarm. “Someone has tampered with the tanks. We are likely to hit a mine.”
Lord Hastings turned to the sailors.
“Men,” he said quickly, “until this matter has been finally settled, I must let you all go. But, each of you keep an eye on your companion, and at the first sign of treachery, shoot him. Search the ship.”
He followed Frank, who had dashed toward the compartments in which were located the water tanks, by means of which the vessel rose and submerged. As he dashed forward there came to his ears the sound of a shot.
The commander of the D-16 redoubled his stride and the men, also having heard the shot, piled after him. As he passed the door to the engine room, the figure of a large man, rushing forth at that moment, struck him squarely and knocked him down.
Lord Hastings was up in a moment and had his opponent beneath him. The latter was a powerful customer, however, and had it not been for the crew, who rushed to their commander’s aid at that moment, it would have fared badly with him.