the boys were just aching in spirit for even a word with the supposed sailor, safely out of range of the lynx-eyed roque, but the latter, after the experience in kiel, stuck closer than a burr to his charges.

the face had passed from the mirror, and the owner of the smiling countenance sauntered through the street door of the café, mingling with many of his kind, smoking and chatting on the sidewalk.

“how will we make it?” tapped billy on the table.

“do not know,” was henri’s answering tap.

roque had paid the waiter for the dinner service, and was placidly puffing a long, black cigar.

“we might take a stroll,” suggested billy.

“something like you did at kiel?”

the secret agent seemed to have amused himself with this sly dig, but it was lost upon his young companions, who were working their wits to invent a getaway.

“how would you like to go to the theater?”

“bully idea!” this was billy’s vote.

“fine!” echoed henri.

[245]

as the three passed out of the café, the boys brushed against the very man with whom they were eager to speak.

billy was inspired at the moment to distinctly address herr roque regarding their return journey to the air camp:

“what time to-morrow do we leave for hamburg, sir?”

roque gave billy a look of stern rebuke.

billy was not worried about the answer he did not get in words. he saw a certain bystander uncover a fine set of teeth, and that was enough.

the play at the theater was a war drama, which was not at all like the real thing, but billy was so delighted with the success of his stratagem at the café door that he was inclined to applaud at both the right and the wrong time.

henri held his praise for his chum, when the two retired for the night.

“it looks like a case of ‘diamond cut diamond’ to me,” he observed, “for you can wager that they would never send a fool over here to buck against the like of roque.”

“i bet they wouldn’t,” was billy’s sleepy opinion.

the next evening the boys were back in the air camp at hamburg.

“you have your hands full, lieutenant,” remarked roque, with a wink and a nod at our aviator boys.

[246]

there is no telling what he might have said had he known what billy had put over on him the night before.

“well,” said the lieutenant, “though it appears that roque has the first call on you, i’m going to keep you busy between times, and as there is nobody around now to scuttle your air mounts you can fly to your hearts’ content.”

they flew the air as they willed, in monoplanes and biplanes, singly or doubly, and, as usual, at the same time these boys managed to fly together into some of the ticklish affairs of earth.

it was on a sunday morning that a jolly party of sailors came over from the harbor to the air camp, and, as they were all supposed to be “true blue,” or, rather, “true gray,” they were permitted to poke their noses into the hangars without restraint.

billy and henri, as the chief aviators present, were counted in as part of the exhibit, and delegated to represent the lieutenant, who claimed this one day for late slumber.

one of the sailors, while he and his comrades were watching the a?rial maneuvers of a zeppelin, had picked standing room as near to our aviator boys as he could conveniently get. so enthusiastic was this man over the majestic flight of the big airship that he grasped the hand of the nearest[247] member of the flying profession, which proved to be henri.

there was something more than the mere pressure of the shake, however, for henri’s fingers closed over a wad of paper.

the sailor kept on cheering, but he did not keep on standing in the same spot.

the paper wad lay in an itching palm, for the holder was itching to open it.

he knew the man who had “delivered the mail!”

billy also had something of an acquaintance with the bubbling sailor.

when the boys jointly read the faint tracing of the tissue message they could not comprehend all that it was intended to convey. that understanding was to come later.

then, too, roque must be in the reckoning.

here we shall have to leave them, flying toward kiel harbor, but their further adventures in their chosen profession will be found in the second book of this series under the title of “our young a?roplane scouts in germany; or, winning the iron cross.”