"The experiments he indulged in," I continued, trying to hide the shiver pimpling my flesh, "were to produce an actual state of absolute zero. It is years since he told me this. I had almost forgotten it." "And exactly what is an absolute zero?" The chief's eyes never left mine. "Well," I protested, "please understand that I also am a layman in these matters. According to my friend, an absolute zero has been the dream of scientists for ages. Once upon a time it was attained, but the secret became lost." "And exactly what is an absolute zero?" Curse the man! I could have struck him down for the chilling level of his tone. I forced myself to go on, realizing that I was damning myself at every step. "An absolute zero is a cold so intense it will destroy flesh, bone and tissue. Remove them," my voice rose in spite of myself, "leaving absolutely no trace." * * * * * No trace! Something attracted my eyes. The chief had opened his hand. The diamond there flashed and sparkled as if mocking me. I pulled myself together, and went on. "It all comes back to me now. One day I came out here and found the professor terribly distraught. He told me that, with the aid of electric currents he had been able to invent the absolute zero, but he could not invent a _container_." "Why?" Those eyes continued to bore into mine. "Because--remember it is years since he told me this--there was difficulty in controlling the power. Besides destroying living things, it would destroy bricks and mortar, stone and iron. Only one substance it could not wipe out--crystalline of diamond hardness. "I know, now!" I jumped to my feet and grabbed the chief's arm. "I know now what he meant. Fool, fool! Why did I not think of it before? This--" I swung towards the cage--"is compensation." Almost panting in my eagerness I went on: "My friend told me that the law of compensation would atone to him for the tragedy of his youth. Absolute zero in suffering would be atoned for by a real state of absolute zero. Chief!" I whirled on him. "Don't you understand? This is the perfected dream of my friend. It is the absolute zero." "Humph! Plausible but not convincing." I slumped back at the officer's words. "That does not explain the professor's disappearance. Even if it did, what about Mr. Lathom? And don't forget this contrivance is worked from outside. We found the diamond inside. Of course, he might have placed it there himself to test the machine," he concluded. "Of course, that's it," I commenced. But I regretted the words when I saw suspicion flicker again in the chief's eyes. Lamely I finished, "And he has probably rushed off, in an ecstasy of triumph, to acquaint professional colleagues." "Without unlocking any doors or taking a car, eh?