Kaye, finding his antagonist crashing, flattened out, and, as he did so, became aware of the presence of the three triplanes and of his chum flying at full speed to intercept them. Without hesitation Kaye joined in the fray. There was no loss of time, for the combatants were approaching an aggregate speed of well over two hundred and twenty miles an hour. A mutual exchange of machine-gun fire produced no visible result, although several tracer-bullets passed perilously close to Kaye's 'bus. Then, banking steeply, the triplanes again endeavoured to close. It was Derek's opportunity, and he seized it. Broadside on to two of the Huns, he let fly with his machine-gun. Down went one of the triplanes in flames, while the second, considerably damaged, rocked violently until the pilot succeeded in getting the machine again under control. Fitting a fresh drum of ammunition, Derek again manoeuvred to renew the attack. As he swung round he saw, to his consternation, that Kaye's 'bus was falling, while long-drawn tongues of flame showed that his chum's machine was not only shot down, but that it was shot down in flames. Filled with a blind rage, and eager to avenge his comrade, Derek dived steeply upon the triplane that had sent Kaye's 'bus on its headlong flight. The German machine-gunner at the after gun was pumping in lead as fast as he could. Bullets, many of them of the tracer pattern, whizzed and screeched past the little British machine. A tension-wire snapped like a harp-string, one end cutting through Derek's flying-helmet and drawing blood from his forehead. He was dimly conscious of jagged rips in his leather coat, of rents in the planes, and particularly of a bullet cutting a deep groove in the three-ply decking of the fuselage. Then, just at the critical moment, the gun jammed badly. Desperately Derek strove to rectify the defect, the 'bus meanwhile steering itself. Once he glanced up to see where his antagonist was. The triplane had vanished. Struck in a vital part a few seconds before the jamming of the British aeroplane's gun, the Hun was falling absolutely out of control. To change over the two automatic-guns was a matter of a few moments; then, again fit for action, the biplane made towards the remaining Hun. The triplane, however, had had enough. With her powerful engines all out she incontinently fled from her much smaller antagonist. Leaning over the side of the fuselage Derek looked earthwards. The ground was well-wooded, and apparently flat, although the pilot knew the deceptive aspect of undulating land when viewed from a height. Two columns of smoke, trending towards the west, marked the spots where the British and the Hun machines had descended in flames.