“We know,” went on Dorothy, “that when the man who is trying to stop all war uses this force, a tremendous amount of radio-active energy is generated, enough to affect reflectoscopes half around the world.”
“We know there is something which is even more than all those things,” I broke in. “We know there is a man who is slaughtering men by the hundreds, in pursuit of his ideal, and that it is our business, in more ways than one, to run him down. How will the data we have on hand enable us to do that?”
As I spoke, Dorothy was sitting looking meditatively out of the window. The fog had lifted a little more. Hamerly straightened in his chair.
“Miss Haldane,” he said, “if you will look straight across the street from where you are sitting, you can see the spot from which the sign fell on the day that Dr. Heidenmuller died.”
Dorothy turned in her chair, and we all crowded about her. Hamerly pointed across the road. There, against the brick wall of an old house, blackened by the smoke of many sooty years, two small rectangles showed in light relief against the surrounding darkness. The sight of those spots, where the supports to the sign had once stood, brought the whole horror of it home to me more forcibly than anything else. The very smallness, the homeliness of the thing drove it in. The accumulated effects of the charged electroscopes, of the wave-measuring machine, of the bodies on the ocean’s floor, of Dr. Heidenmuller’s death, and of the gas we had just found, rose to their very crest in those small, light gray spots, less sullied than the rest of the wall.
“And there is where the wooden sign fell down, and its iron supports disappeared,” said Tom reflectively. “Jove, I’d like to have seen it happen. If anybody had seen it, though, he wouldn’t have believed his eyes.”
We were still standing, peering out through the rising mist, when Dorothy spoke out excitedly. “That’s the next clue, there’s nothing else that will do so well,—the hunt for disappearing iron.”
“What good will that do?” said Tom. “We know where iron has disappeared, and we’ve run everything down as far as we could. It isn’t likely that Heidenmuller or the man went around shooting off signs for fun.”
“Of course not,” answered Dorothy impatiently. “But don’t you see the man must have had a laboratory, or lodgings, anyway, somewhere in London, if he got his data and his power from Dr. Heidenmuller here. When Dr. Heidenmuller let his discovery get away from him, it killed him, and caused all the metal which it reached to disappear. Now, the man hasn’t been killed by his weapon, unless it happened very recently, but it’s perfectly possible that he might have allowed some of his magic substance to escape without injury to himself. If that happened, it would destroy any metal at hand. If we could find some place where iron disappeared, we might get a direct clue to the whereabouts of the man. It’s worth trying, anyway.”
“I’m sure it is,” I cried. “Tom, you old doubter, speak up and admit Dorothy knows twice as much about it as you and I put together.”