As the chums were about to pass into the building there was a hail.

"Wait a minute, Jack!" called one of their fellow pilots, hurrying up with some object in his hand at which the two boys stared with rising curiosity. "I've got something here for you!"

"For me?" cried the youth addressed. "I'm ever so much obliged, but it strikes me I've got beyond the point of playing with a toy balloon; though honestly now, when I was a kid I used to be pretty fond of sailing one of 'em at the end of a long string, until it would get away, and leave me staring up while it climbed toward the clouds."

"Oh, this one is about past doing any climbing, I should say," replied the pilot, laughing at Jack's description of his childish woes. "In fact, it's been out during the night, and the heavy air forced it to come down. Listen, and I'll tell you a strange story that will make you believe in fairy tales."

"Go on then, please," urged Jack. "You've got me all worked up already. So there's a history attached to this little balloon, is there?"

"There was something attached to it, something that may mean much or little to you fellows," came the reply. "This thing was found by a French dispatch bearer on his way across country. Out of curiosity he stepped aside to look at the bobbing red object he had noticed among some bushes in an open field. When he found that it had a paper fastened to it, which on the outside had an address, he concluded to bring the whole business along with him. He came here half an hour back inquiring for Jack Parmly, and on finding you were away at the time left the balloon and the paper in my charge. Take it, and see what the message is, Jack!"

CHAPTER V
THE STRANGE WARNING

"Open it, Jack, and see what the message is," urged Tom, as his chum stood with the scrap of damp paper held between his fingers, having allowed the sagging little toy balloon to fall at his feet.

Jack was thinking just at that moment of the other message his companion and he had found attached to the homing pigeon. But of course they could not possibly have any sort of connection!