Denbigh handled it gingerly. There was something hard inside. Curiosity prompted him to unbuckle the strap and open the case. Within was a pocket-compass. What was more, it was a spirit one and seemingly in good order. Without compunction the sub abstracted the compass and slipped it into his pocket.
As he did so he was startled to hear a deep groan. It seemed to sound close to his ear. He wheeled abruptly and shot a glance in the direction of one of the bunks, thinking that he had made a mistake in deeming it untenanted.
There was no one there. Again the groan was repeated. This time the sound seemed to come from the adjoining cabin--the one occupied by Pat O'Hara.
A hole in the bulkhead attracted Denbigh's notice. It was the aperture drilled by the Germans when they made their ineffectual attempt to chloroform the three British officers.
Through it Denbigh could see but a very small portion of the next cabin, but sufficient to observe O'Hara lying on his back in his bunk. He was writhing and groaning. His eyes were wide open and rolling in a horrifying manner.
"I say, old man," whispered Denbigh. "What's wrong?"
At the sound of his voice O'Hara raised himself. He tried to speak, but could not. With an effort he rolled out of his bunk and stood clinging to the edge for support.
"Open the door," said Denbigh peremptorily. "I cannot get in."
"If he's not able to it's the last straw," he soliloquized. "I'll have to give myself up and get assistance."
With a great effort the Irishman lurched across the floor and removed the chair which had been wedged against the lock. Then, unable to regain his bunk, he pitched inertly upon his face.
Denbigh waited no longer. He darted into the alley-way, not even waiting to see if everything were clear. The door opened easily. He entered, and lifting O'Hara as easily as a child placed him on his bunk.
"Felt jolly rotten almost as soon as you cleared out," muttered the Irishman. "Sorry, but I couldn't help it."
"I don't suppose you could," replied Denbigh, for O'Hara's regret was genuine. "I'll ring for assistance."
He touched the electric bell. Then, and only then, he remembered that he had to replace a portion of the lock. Grasping the screw-driver he set to work, and had just driven home the last screw when the locked turned, and a petty officer entered.