“But how comes it you are leaving so early the next morning?” asked the officer, with a little fresh suspicion in his manner. “We have a most beautiful and renowned city here, and travelers usually find it difficult to tear themselves away from it, even after a stay of days. You seem to have been in a great hurry.”

“We own up that we are, sir,” continued Jack. “You see, the first thing I did on arriving was to hasten to the postoffice for our letters from home. It was then that I realized the city was in a feverish state of excitement. I suspected what must have happened, for we heard rumors when above. I managed to learn that war had been declared by Germany on Russia, which would mean for Austria-Hungary, too. And after we had talked it all over we decided that it would be best for us not to waste any time here, but hurry along our way.”

“Would you mind showing me those letters?” asked the officer.

“With the greatest of pleasure, sir,” Jack told him. “Boys, hand him the last ones you received, please.”

The other took them as they were thrust out. He examined the postmarks as if making sure of the dates, and also read each name in turn. Then he deliberately opened that belonging to Jack and seemed to be glancing over it, though the boy felt rather surprised to see him do this.

Still, it was good to find the officer nodding his head as he gleaned something of the contents. At least he could see it was genuine, and that counted for a good deal.

“I am quite satisfied now that you are just what you claim to be—tourists, who have no connection with our enemies, or those who in a short time we must look on as such. You are wondering, no doubt, why I went so far as to pry into the contents of your letter from home, and I believe an explanation is due. To tell the truth, we rested under the belief that you were four desperate young Serbian youths, who were said to be on their way up the Danube bound for Vienna, with the mad intention of trying to assassinate our good kaiser, Francis Joseph, just as the Austrian heir apparent to the throne was killed not long ago.”

Buster could not keep from giving a little gasp at hearing this. Really never before, so far as he knew, had he been taken for a desperado. He did not know whether to be ashamed or flattered. It would be something with which to thrill those boy comrades at home, if ever they were lucky enough to get safely back again.

“That would be a serious charge against us, I am sure,” said Jack; “but it pleases us to know that you are now convinced we are not what you thought. Seeing four strangers in a boat, and all young at that, of course made you suspicious.”

“The fact that you were headed down-stream puzzled us considerably,” continued the officer, apparently willing to explain things in order to prove that he and his comrades were only doing their duty; “but we figured that something may have caused a change in plans, perhaps the breaking out of war, and that the four desperate Serbians were on the way back to their native land.”