And then his responsibility, in view of the discovery he had made, flashed upon him.
"I must warn the flagship at once," he exclaimed, seizing the oars and sending the boat forward with a spurt.
But after a couple of strokes he suddenly stopped again.
"What a fool I am!" he exclaimed. "By the time I can row out to the flagship, it will be too late. They must be warned instantly, and there is only one way of doing it."
He reached for the signal rockets he had brought at the rear admiral's order. Should he fire them?
Those on board the strange boat that was nearly abreast of him did not know that he was there. If he gave the signal it would betray his presence, and no doubt lead to an attack upon himself in his open boat.
Clif looked far out to sea for a moment, half hoping to see the flash of the searchlight play upon the water, and lead to the detection of the strange craft.
But the delay was only momentary.
"It is my duty to warn the ships," he exclaimed, as he set a rocket up in the stern, and drawing a match from his pocket, struck it upon the seat of the boat. "Here goes!"
A moment later, with a sharp whirr and a flash of light, the rocket shot up into the air. A second and third followed; then Clif sprang back upon his seat and seized the oars.