Experience had taught us that in the Zeppelin raids upon England the airships generally approached by crossing the coast-line between Lowestoft and Margate, therefore I decided upon a district that would be the centre of a danger-zone. Having studied my map I saw that my most direct route would be over Tonbridge, thence by the railway line to Sevenoaks, and then north-east till I could pick up Gravesend--which would be easy on account of the river Thames--and afterwards due north would bring me to G--, which would be easily distinguishable by certain landmarks. We had wheeled out the machine, and I was tuning her up before starting, both Teddy and I ready in our air-clothes, when Theed, who was giving the machine a final look round, suddenly gave vent to an ejaculation of dismay. "Why look, sir!" he cried. "What's this?" I hopped quickly out of the pilot's seat and, joining him, saw to my surprise that, beneath the wooden petrol-tank a fine insulated twin-wire had been, placed, and upon it, tacked lightly to the wood, was a small disc of some black-looking material through which the fine wire ran. In breathless eagerness I traced the wire and, to my horror, saw what a devilish contrivance it was. The twin-wire had been connected up to the battery that ran the lamp over my map and instruments, therefore had I switched on the light at night, it would have failed, for it was intended that the current should ignite that little disc of inflammable material and explode my petrol-tank behind me! Truly, the device of those crafty and subtle enemies was a devilish one. That wire had been connected up by an Invisible Hand--by the hand of one who certainly knew the most vulnerable point of the machine. Teddy and Roseye both stood aghast at this latest revelation. Then, when I had disconnected the wire, I placed it with the little black incendiary disc upon the ground and connected up the wires to an accumulator from the car. In a moment the black substance shot into a fierce red flame which burned and spluttered with intense heat for fully five minutes. From the barn, a few minutes later, Theed emerged carrying a piece of the wire, evidently discarded by the intruder who had so swiftly and so cunningly prepared another death-trap for me. A further hour we spent in making a second examination of the machine, and then having appointed to meet that evening at the old King's Head, in G--, at seven o'clock, I climbed into the pilot's seat and, with Teddy at my side, we shot forward and soon left the ground heading for the railway line which I knew would run from right to left across our track at Tonbridge.