Derek had to make up his mind. There was a choice between flight and pure bluff. He chose the latter. The Hun and the British machines were on widely-converging courses. Already the lurid colourings on the former's fuselage were plainly visible. He was closing with the evident intention of taking stock of a possible opponent. "I'll make him sit up," declared Derek, as he swung round and headed straight for the Hun. Count von Peilfell--for it was he who piloted the gaudily-painted 'bus--at first made no effort to avoid a possible collision. It was not until Derek was within fifty yards that he dived steeply, and, looping, came up under the tail of the British biplane, a manoeuvre which Derek encountered by looping and practically sitting on his adversary's tail. Thus both the British pilot and the Hun had a chance which they ought to have seized, but neither of them opened fire. Derek knew why he could not; his opposite number was in a similar plight. For a space of four minutes the pair engaged in bluffing tactics, each trying to "put the wind up" the other by bearing down at full speed and then adroitly avoiding a disastrous collision. Then the encounter fizzled out. British and Hun machines set off on parallel courses at a bare fifty yards apart, the respective crews laughing and gesticulating at each other as if mortal combat in the air was a thing unheard of. "In working order!" shouted Kaye, tapping the rear machine-gun. "Good!" yelled Derek in reply. "We've had enough of this joy-stunt. Let rip right aft." Without a shadow of doubt the Hun, had he been similarly placed, would have fired a tray of ammunition straight at his opponent, but British airmen are made in a different mould. Even at critical moments the innate sporting instinct shows itself. Directing the muzzle of the gun away from the tempting target afforded by the gaudily-hued Hun, Kaye let rip. For a moment Von Peilfell's face--or rather that portion of it not masked by his goggles--showed consternation and astonishment; then, realizing that the "fool Englander" was chivalrously throwing away a decided advantage, he gave a farewell wave with his gauntleted hand, banked, and was soon a mere speck in the sky. Four minutes later EG 19 passed over the opposing lines, not a hostile air-craft being in sight, although five thousand to seven thousand feet below the air was "stiff" with 'planes bearing the distinctive red, white, and blue circles. Evidently Fritz was in for a very sticky time, to use a common service phrase. A violent bump, followed by a succession of sideslips that well-nigh flung Kaye from his precarious perch, gave unpleasant warning that even at a height of nine thousand feet there are dangers from the ground. Ten, perhaps twelve, miles away a long-range naval gun was busily engaged in shelling the Boche back-areas, and a fifteen-inch shell approaching the zenith of its arc is no respecter of persons.