Under the tutoring of Hiram Nelson, the wireless scout, the others had all become fair operators. It was agreed that day and night one of them should be at the apparatus, seeking for news of the green motor boat.
It was the ensign's opinion that the craft would not put into a port immediately, fearing a hue and cry, but would cruise about or hide in some little frequented part of the coast. But he hoped that if the wireless "caught" some vessel that had spoken to her, he could at least obtain a line on which direction she had taken.
The first "session" at the wireless was taken by Hiram, then came the others in rotation; but when at ten o'clock that night Donald, who had learned wireless on his father's yacht, came on duty, there had come no word from the air of a green motor boat. Several ships had been spoken to, but not one reported anything to give the boys hope.
"Well, good-night, old man," said Merritt, as Donald, who relieved him, came on duty, "and good luck."
"I'll keep a good watch out, all right," was the earnest response. "It's our only way to get poor old Rob back."
"I'm afraid so," sighed Merritt, leaving the place with a despondent air. As Donald had said, it was a chance—but what a long, seemingly hopeless one!
Donald, left alone, began sending out calls, and every little while he paused for an answer out of space to his appeals. As he pressed the sending key the blue, lithe spark leaped and crackled between its points like a fiery snake. Then all would become silent again as he listened for an answer to his call.
Once he caught a steamer bound north and carried on quite a conversation with its operator. He felt quite lonesome when he closed down his sending apparatus with a parting "good-bye."
It was very still about the encampment. So still, in fact, that the boy began to feel more and more lonesome. He longed for someone to talk to; but he knew that chance would not come till Tubby, his relief, appeared.
The stout youth was almost due when Donald suddenly got into communication with a steamer called the Cambria, bound north from New Orleans to New York. He put his customary query about the green motor boat.