“Go to it, old top!” exclaimed Macaroni, dropping into what he thought the latest English slang.  “I’m going to turn in.”

The lanky helper of the moving picture boys had spent the hours of his watch with his eye close to a small hole that had been bored in the door of the boys’ stateroom.  The hole gave a view of the staterooms of Lieutenant Secor and Mr. Labenstein, which adjoined.  And, as Charles had said, he had not observed either man leave his apartment.

If what the boys had only guessed at were true—­that one or both of the men contemplated giving a signal to the enemy by means of the flashlight—­the time for it had not yet come.

“Well, I’ll try my hand,” Blake said.  “You turn in, Mac, and if I need any help I’ll call you.  If I don’t see anything up to about one o’clock I’ll let Joe do his trick.  Good-night and pleasant dreams.”

Charlie did not answer.  He was already in his bunk and asleep, for he was tired, and the last half hour of his watch he had kept himself awake with difficulty.

Then Blake began his turn of duty.  He took a position at the door where he could look out through the hole into the dimly lighted corridor.  He had a view of the doors of the staterooms of the two men who were under suspicion, and as soon as either or both of them came out he intended to follow and see what was done.

For an hour nothing happened, and Blake was beginning to feel a bit sleepy, in spite of the fact that he had rested during the early part of the evening, when he was startled by a slight sound.  It was like the creaking of a rusty hinge, and at first he thought it but one of the many sounds always more or less audible on a moving ship.

Then, as he tuned his ears more acutely, he knew that it was the squeaking of a hinge he had heard, and he felt sure it meant the opening of a door near by.

Through the hole he looked at the door behind which was Levi Labenstein, whether sleeping or preparing for some act which would put the ship in peril and endanger the lives of all the passengers, could only be guessed.

Then, as Blake watched, he saw the door open and the German come out.  Labenstein looked around with furtive glances, and they rested for some little time on the door behind which Blake was watching.  Then, as if satisfied that all was quiet, the man stole silently along, the corridor.

“Something doing,” thought Blake.  “Something doing, all right.  He has something in his hand—­probably my flashlight.  Much good may it do him!”

As Labenstein passed the stateroom where Lieutenant Secor was quartered, that door opened softly, but not until the German was beyond it.  And then Blake saw the Frenchman peer out as though to make sure his fellow-conspirator was fairly on his way.  After that the lieutenant himself emerged and softly followed the German.

“Both of ’em at it,” mused Blake.  “I’d better rouse Joe and let him keep track of one, in case they should separate.”