The two citizens with the tripod set it down between the old dusty joists upon which the floor boards had rested, and of a sudden a most abominable glare, like the white heat from molten iron, shot in a shaft upon a corner in the uncovered lower flooring. It was brilliant beyond the dreams of avarice. It revealed like remorse. Mr. Collop with an agility surprising in a man of his build, leaped down that little distance, and kept on shouting directions. "That's right now! Sweep it along! Sweep it along! Sweep it along!" The blinding shaft of light slowly traversed the edges of the shallow void from end to end, from left to right. "Now back again!" said Mr. Collop. "Now back again!" The intense beam travelled back in another band, slightly nearer, from right to left; and all the while the detective followed with keen eyes every patch which it successively illuminated. It was not a long process. Three or four minutes at the most. And while it continued, the Home Secretary, perched in security on his window-sill, was interested in spite of himself: new science is always a toy.... And that was how they searched for the jewels in the flooring of the West Room. Mr. Collop's hand went up, and the blinding shaft of light disappeared as suddenly as it had come. "That'll do, lads!" he said. "We know one thing now, any'ow. It didn't get down through the flooring; that's certain. Now then, if you please, we'll open the furniture." Mr. de Bohun did not please. "Surely, surely it can be spared," he begged. "It's Victorian." "Now, sir," protested Collop firmly, "I'll be responsible for nothing unless I'm pursuing my own method." The Home Secretary sighed and surrendered. With deft fingers two of the three extras began picking out the stitching of the chairs after every loose cushion had been lifted, shaken, and put aside. It was beautiful to see such expert work; at least, it was beautiful in Mr. Collop's eyes; but the Home Secretary almost shed tears. Those chairs were his father's! The Great Peal, the immortal Benjamin Israel, had graced them. And again--who was going to pay for all this? All the edges of the leather stood out; the secret places were revealed. There was no emerald. Mr. Collop beamed with satisfaction. "That, sir," he said triumphantly, "is the end of what we've called our _Negative_ process. Hey! Number One!" And he ticked off on his thumb, as he had done before. "We are now assured," he boomed, tucking his thumbs into the armholes of his waistcoat, "that wherever the Em'rald may be, it's not in this room. Stay a moment! I'd forgotten! The pictures down, please!" Again the owner gave tongue. "Do you _really_ think, Mr. Collop ..." "Yes, I do," answered Mr. Collop with decision. "Come. Smartly, lads!"