His words served as the signal to the others. Every fellow immediately hastened to dive into his breast pocket and produce the necessary paper, which was always kept in an especially safe place for fear of trouble in case of its being lost.

The officer took the sheaf of papers and proceeded to critically examine the passports, as though looking for signs of fraud. Buster watched him anxiously. He had heard that when war came upon a country all ordinary protection for tourists is annulled, and even passports may not be worth the paper they are written on.

Greatly to Buster’s relief he saw that the tall officer did not look at them so ferociously after he had scanned the papers, which he now handed back to Jack in a bunch.

“They seem to be perfectly correct, so far as I can see,” he proceeded to say; “but perhaps you would not mind explaining what your object is in coming down the Danube in this powerboat?”

“I’ll be only too glad to do that, sir,” Jack announced, with one of his winning smiles that always caused people to feel kindly toward him. “Over in our own country we have three motorboats, with which six of us in times past have made many exciting cruises along the great rivers, and the coast as well.”

The officer nodded his head, while his face lighted up. Evidently he could appreciate the love for adventure that induced these healthy specimens of boyhood to want to be in the open air all they could. Perhaps whenever he had the chance for an outing he might have been found off in the mountains, hunting the wild boar, or it might be in pursuit of the nimble chamois.

“When we had a chance to come to Europe this summer,” continued Jack, “we decided that the thing we would like best of all would be a long trip down the beautiful blue Danube. I had just been reading an account of a cruise taken by an Englishman from near the source down to the Black Sea. While we couldn’t spare the time for all that, we could come to Vienna, find where a suitable boat could be chartered half-way to Budapest, and make our start there. And, sir, that is what we have done. We are now just two days on the way.”

“I admire your courage, as well as your choice of the Danube for your trip. Many a voyage have I taken on its waters when I was younger. But how long have you been at Budapest, may I ask?”

Jack knew that there was only one way to treat such a questioner, and that was by being perfectly frank with him.

“We only arrived late yesterday afternoon, to tell the truth, sir,” he admitted.