Suddenly a huge, ill-defined shape lurched past the battleplane, passing less than two hundred feet underneath. In spite of the terrific speed, for the two objects were moving in the opposite direction and at an aggregate rate of one hundred and eighty miles an hour, both lads recognised the shape as that of a Zeppelin.
Desmond Blake saw it, too, and acted promptly. In a few seconds the battleplane had made a semi-circular motion and, "all out," was following the night-raider.
Athol sprang to the machine-gun but the pilot waved his hand to indicate that the weapon was not to be used. Already the Zeppelin, having gained a great distance during the change of direction on the part of the battleplane, was out of sight.
"No use," he exclaimed hurriedly. "Only dummy cartridges. Must blame the Defence of the Realm Act for that."
Seven minutes later the Zeppelin was again sighted. Apparently she had been engaged in a raid over the Midlands and had lost her way. She was moving jerkily, and was down by the stern. Whether that was owing to injury from anti-aircraft guns or merely through the accumulation of snow on the upper part of her envelope the lads could not decide.
Unperceived by the crew of the Zeppelin the battleplane soared majestically overhead until a vertical distance of less than a hundred feet separated the gas-bag from her winged rival.
"If we had ammunition we should have her at our mercy," remarked the inventor.
"Take charge for a few minutes, Athol. I want to give her a little reminder of our meeting."
The lad gripped the steering levers. So strong was his faith in the masterpiece of the inventor that he handled the swiftly-moving battleplane as faultlessly as if his acquaintance with the mechanical bird had been of two years' duration rather than of a few hours.
Meanwhile, Blake descended to the interior of the fuselage, returning presently with a long steel marline-spike. Through the hole in the rounded end he threaded a string of red, white and blue ribbons for the joint purpose of steadying the improvised dart in its flight and in order to leave no doubt in the minds of the Huns of the origin of nationality of the weapon.