"I went back to the piazza and caught up a pair of stereo-binoculars that were lying on the table. There, shining like a star through the close curtain of green that veiled 'The Thimble,' was the projecting end of a highly polished tube of steel. And even as I gazed a man's face peered out as though in the act of sighting--Aram Balencourt! "Then I understood. The tube was the means of projecting some enormously powerful heat-beam whose nature must be akin to that of the so-called X-ray. The article I had been reading not ten minutes ago--what was the title?--'Radium, the Wizard Metal'--that incomprehensible substance, forever sending forth its terrible emanations, yet never diminished by even the ten-thousandth part of a grain--a natural force whose properties and functions were but imperfectly understood, even by the learned men who had succeeded in isolating it, an agent of such enormous potency that an ounce or two might serve to put a battle-ship out of commission--a couple of pounds and the universe itself were endangered. Even now from that steel tube, sighted so carefully on the pedestal of the sun-dial, billions of ions might be rushing, invisible to the eye, but certain death to whatever of animal existence they chanced to encounter. There was the pigeon lying dead on the walk. "'Do hurry, George,' called out Betty's thin, sweet treble. She stood at the entrance to the pavilion and waved a tennis-racquet impatiently. "'Coming,' was the cheerful response, and Estes turned the corner of the house. He took the gravelled path at full speed. In an instant or two at the farthest he would be passing between the sun-dial and the dead pigeon, in line with those deadly radiations. "We had been playing a little single-wicket earlier in the day, and a cricket-ball lay on the wicker table at my hand. I could not have uttered a word or a cry to save my life--to save his--but instinct held true. With a full, round-arm sweep the ball left my hand, catching the boy squarely on the forehead. He fell within his stride. "Betty was with us on the instant, but I seized and held her despite her struggles. Naturally, she thought I had gone mad. Then I looked over again at 'The Thimble,' just in time to see a sheet of palest-colored flame shoot up from the island. The dense mass of green foliage seemed to wither and consume away within the tick of a clock. Through the glass I caught a glimpse of a dark figure that rolled down to the water's edge, clutching feebly at the shifting shingle. Perhaps a log, after all--it lay so still. "An instant later 'The Thimble' disappeared in a cloud of grayish vapor, the dull sound of an explosion filled the ear, and the ground under our feet trembled. There was nothing to be seen, even with the glass, save a light scum covering the water and some fragments of charred tree branches. But the air about us was full of a fine dust that powdered Betty's hair, as though for a costume ball, and made me cough consumedly.