But even Henri, as a self-claimed prophet, had no idea that the man he knew as Anglin would bob up in Strassburg, though the city was as likely a point as any in the war zone for secret service activity.
When Billy jokingly asked his chum if he had any predictions to fit this occasion, Henri admitted that his second-sight "was off the job."
It soon developed that the secret service experts of both sides were matching wits in this quarter. Reported in Roque's calendar of the week was the giving away by one of his workers in hostile territory of a French attack on the Germans during a fog, with the result that the intended surprise resulted in a rout, and the assailing force mowed down almost to a man. The mute testimony was in a low-lying valley out in the Lorraine field—700 graves in a space 200 yards wide and about 50 broad.
Then a counter-move, wherein the French had advices from some source unknown of the coming flight of a Zeppelin out of the Black Forest, and three French aëroplanes were ready to charge at the big dirigible, which, after a continuous exchange of fire lasting forty minutes, made narrow escape to the north, just when the lighter craft had succeeded in getting above it for a finishing stroke.
As it came about, and in a queer way, too, the boys were the first to blunder upon a cunning ruse being resorted to by a smooth worker in getting away information under the very nose of the astute Roque.
Billy and Henri, indulging their liking for high places, and having a little leisure to look around, found a favorite perch in one of the famous towers of Strassburg. They were interested, as airmen, in watching the daily flying exhibit of the pigeons 'round about.
"Have you noticed, Henri, the streak of feathers every once in a while that don't stop to associate with this housekeeping bunch? I've seen two of these birds already this morning; they act just like an aëroplane, circle about, and then break away like a bullet. There's one now. Look!"
Henri followed the aim of Billy's finger, and, sure enough, a long-tailed flyer was cutting the air like greased lightning in a straight line west, without the slightest notice of the many of its kind pluming themselves on neighboring towers and housetops.
"They make long visits," commented Billy; "I've watched, but never see any of these air hustlers come back."
"That's funny," observed Henri, "let's borrow a glass this afternoon and find out, if we can, where they start from. Why, this is good sport; we'll be wearing badges next as pigeon detectives."