"I mean that I intend destroying all this excellent espionage work of yours. You've lived here for two years, and have been very busy travelling in your car and gathering information. But," he said, "you were a little unwise in putting upon your car the new Feldmarck non-skids, the only set, I believe, yet in England. They may be very good tyres, but scarcely adapted for spying purposes. I, for instance, noticed the difference in the tracks the wheels made one evening when you met your wife outside Metfield Park, and that is what led me to you." "You'd destroy all my notes and plans!" he gasped, with a fierce oath in German. "You shall never do that--you English cur!" "Then stand aside and watch!" he cried, withdrawing from the room on to the landing. "See, look here!" and he opened his bag. This caused both men to withdraw from the room to peer inside his bag. With a quiet movement, however, Ray flung a small dark object into the centre of the room, and in an instant there was a bright blood-red flash, and the whole place was one mass of roaring flames, which, belching from the door, caused us all to beat a hasty retreat. In a moment the place was a furnace. The spies shouted, cursed, and fired their revolvers at us through the thick smoke, but we were quickly downstairs and out in the road. "That will soon drive out the rats," laughed Ray, as we watched the flames burst through the roof and saw the two men escape half dressed through the window we had opened. And as, with the red glare behind us, we hurried back to the spot where we had left our car, Ray remarked, with a laugh of triumph: "Stolberg bought that place two years ago with money, no doubt, supplied from Berlin, so he's scarcely likely to come upon us for incendiarism, I think. It was the only way--to make one big bonfire of the whole thing!" CHAPTER IV HOW THE GERMANS ARE PREPARING FOR INVASION "We're going down to Maldon, in Essex," Ray Raymond explained as we drove along in a taxi-cab to Liverpool Street Station late one grey snowy afternoon soon after our return from Norfolk. He had been away from London for three weeks, and I had no idea of his whereabouts, except that one night he rang me up on the telephone from the Cups Hotel, at Colchester. An hour ago he had returned to New Stone Buildings in the guise of a respectable mechanic in his Sunday clothes, and, full of bustle and excitement, urged me to run across to Guilford Street and assume a similar disguise. Then, each with his modest bag, we had hailed a motor-cab and given the man instructions to drive to the Great Eastern terminus. "You've read the affair in this evening's paper, I suppose?" my companion asked; "the mystery at Button's Hill?" "Yes," I replied. "Are we about to investigate it?"