Plumbo was waiting, and as they hastened down the street he explained in his odd rhyming speech just what had happened. He could not describe the men except to say that one had whiskers on his chin. In a part of the country where this is a favorite facial adornment this information was not much of a clew.
It took the alarmed party much less time to reach the wharf than they would have thought was possible. In fact, almost the whole distance was traversed at a run. But when they arrived at the wharf and a lantern, which Dr. Perkins had had the foresight to bring along, had been kindled, they found nothing to inform them as to what had taken place. The doctor had not expected to find Plumbo’s three men there, but he had had an idea that he would find something damaged about the Sea Eagle. But as careful an examination as it was possible to make by lamplight failed to reveal any trace of damage.
Naturally this, instead of helping to clear the mystery, only deepened it. What object could the men have had who had sent Plumbo off on his wild goose chase if it had not been to wreak injury to the Sea Eagle?
“Maybe they were some inventors who wanted to steal your ideas,” suggested Harry, recalling some experiences of their own with unscrupulous aviators.
But Dr. Perkins shook his head.
“Every important feature of the Sea Eagle is fully covered by patents,” he said; “there isn’t a single idea they could appropriate in the short time they could have spent here anyhow.”
Harry had to admit that this was so, but to tell the truth his thoughts were centered more on Frank and on the strange circumstances surrounding his disappearance than they were on the Sea Eagle.
“I’m as certain as that daylight will come again that Frank fits into this mix-up somewhere,” he said, voicing his thoughts, “but the question is where?”
“Well, he’s not here now, that’s certain,” declared Dr. Perkins. “I propose that we should return to the hotel now that we have discovered that no damage has been done. He may meet us there.”
“Let’s search the wharf first,” said Harry, but, naturally, even their painstaking search failed to reveal any trace of Frank’s fate till, all at once, Harry, who was carrying the lantern, came upon his brother’s cap lying where it had fallen in the scuffle among the boxes.