But if the lads against whom their menace, their malice and their machinations were directed were not aware of the activities of these German spies and servants, the Secret Service of the United States was, and its watchful eye was upon them—more cleverly discerning than ever the eye of Constabule Allerson had been in following the movements and thwarting the purposes of that agent of evil, Henryson.
And even as these Hun tools now were watching the American plane disappear over the horizon, so two Government agents, from the secret recesses of the long abandoned Coast Guard storehouse were observing their every movement by the aid of two pairs of strong marine glasses.
Apparently mere curiosity-seekers and hangers-on around the scene of the proposed Transatlantic hop-off, these two men had been constantly on guard, and as a matter of fact, to continue the concealment of their own identity, had apparently unconsciously dropped the tip which had first put Captain Allerson close on the trail of the incendiary and plane-fixer, Henryson.
So it was that within the next ten minutes one of the two, first making certain that he was unobserved, hurriedly left the rear of their hiding-place, leaving his companion there to continue the vigil while he took a circuitous route and a little later, in what seemed to be the most aimless manner, and with a vacant grin on his face like the veriest bumpkin, strolled up to the hangar where all these hasty preparations were going forward.
The man on the door, who gave all the evidence of merely loafing there, but who in reality was an eagle-eyed "look-out," saw the apparent backwoodsman approaching and returned his grin with a scowl.
"Howdy?" the disguised Secret Service man saluted, evidencing an intent to enter into conversation.
"Same to you; what d'you want?" the man on the door returned sharply.
"Nothin', less you got a spare chaw on ye," the other replied.
"Don't chew," came the surly reply.
"Smoke?" The agent, entirely ignoring the other's tone and manner, produced and offered a pouch of tobacco.