“Jack, we’d like to talk to you a moment if you can break away.”
Crandall’s eyebrows raised slightly; he looked at Da Silva inquiringly. The swarthy detective nodded.
“Mr. Crandall—”
“Call me Jack.” The stocky man considered his offer and then placed a condition upon it. “Unless, of course, you’re going to arrest me for disturbing the peace with this brawl. In that case I suppose Mr. Crandall would be more appropriate. Look more dignified on the blotter.” He glanced about. “Breaking away is no problem. I doubt if any of my guests know I’m here. Or even that it’s my party. Come on — follow me.”
He led them into the thick of the crowd, carrying his glass high, in the manner of Joan of Arc leading her armies into battle. The hallway was the first bastion to be won; the struggle here was only slightly less fierce until the bathroom had been reached and passed. Beyond that there appeared to be only stragglers. Crandall twisted the knob of a door beyond, peeked in to check its occupancy, and then held it while the other two passed in. He closed it behind him. The sudden silence was startling after the noise of the party.
“My den. Soundproofed, thank God! And, oddly enough, unoccupied. It’s amazing how many of my guests prefer to wrestle on a couch upholstered in leather. Doubtless a fetish.” Crandall grinned, nodded toward large leather chairs, and sank into one himself. He sipped his drink and nodded. “I should have thought of hiding here myself. I didn’t realize how noisy it was out there. If you did arrest me for creating a nuisance, I wouldn’t blame you.”
Da Silva smiled broadly. “Frankly, I wouldn’t blame me either. But that’s not why we’re here.” His smile disappeared; he became serious. “Mr. Crandall — Jack — what I’d really like from you, as I told Wilson, is a short, fast, ten-minute course in radioactivity.”
Crandall looked at him sardonically.
“Are you sure you wouldn’t want to spend fifteen minutes and get the long, full course?” He shook his head, smiling. “I couldn’t cover the subject in ten hours or twice that long. And I’m not talking about the physics involved; I couldn’t cover that in any amount of time, because it isn’t my field. There are hundreds of books on the subject, each one covering a different phase. What phase are you interested in? Its history? What it is? Where it’s used?” His smile broadened. “Why don’t you just ask me questions? And give me a fighting chance not to look uninformed in front of Wilson?”
Da Silva twisted his brandy glass between his large hands staring at the floor. His eyes came up.
“Well, to begin with, just what is radioactivity?”
Crandall set his drink aside and clasped his hands in his lap. He seemed to be forcing himself to answer soberly.
“The definition of it is the emission of energy, basically the property possessed by certain elements — whether free or combined — of spontaneously emitting certain rays of energy owing to the disintegration of the nuclei of their atoms. The chief elements I’m talking about are radium, uranium, and thorium, although there are others.” He spread his hands. “The actual mechanics of this disintegration is in the field of physics. I’m more familiar with the end result.”
“You said ‘free or combined.’”
“Yes. Actually, none of these elements is found in its free state; they are in combination with other metals and have to be separated. There are, literally, hundreds of such radioactive combinations. All the halides, for example — the combinations of salts of such materials as bromine and chlorine — with the specific metal itself.” He smiled. “Don’t get me involved in the chemistry of the subject either. It’s been a long time since I went to school, and in the practical aspects of the subject of mineralogy, the chemistry gets lost in the shuffle.” He tilted his head toward the bookshelves. “I have plenty of material here, if you’re interested in borrowing it. And I have plenty more in my office at the embassy. You’re welcome to any of it.”
Da Silva smiled grimly. “One of my major problems is that I really don’t know what questions to ask. I was hoping that if you gave me a short lecture, you might say something that would give me an idea.” He sipped his drink, thinking, and then set the glass down, leaning forward. “Let me ask you this: Could mere contact with a radioactive material cause an ordinary object to retain enough of that radioactivity to activate a Geiger counter?”
Crandall raised his shoulders.
“If I understand you, if some of the radioactive material itself adhered to your ordinary object, I should say yes. It would have to be a sufficient amount, of course, and the source would have to be sufficiently strong, but it could happen.” He thought a moment and then looked at Da Silva steadily. “You realize, I’m sure, that skin contact with some of these materials can be quite dangerous.”
“I’m not talking about personal contact; at least, not skin contact. Actually, I’m talking about a shoe—”
“A shoe?”
“Yes. Let me ask you this: If one had in his possession a shoe that activated a Geiger counter, could the shoe be analyzed to tell which radioactive material was involved?”
“I doubt it.” The fringed head shook. “Not unless there was enough of whatever was adhering to it to analyze. And separation and analysis of most of these compounds are difficult enough even with large samples.” He smiled. “It would probably be easier to find out where the man worked, because, frankly, if I found a shoe that was radioactive, I’d suspect a job in a separation plant or something of that nature. It’s rather rare to walk around on radioactive material and not know it.”
“I wish it were that simple.” Da Silva sounded unhappy. “We don’t know whether he knew it or not.” He thought a moment. “Let me go a step further. Suppose — just for the sake of argument — that the actual source of this radioactivity could be identified. I mean, the actual mineral or combination of minerals. Then, based on that identification, could one tell precisely where that material had come from? I mean, to be more specific, in Brazil?”
Crandall considered the question for several moments before answering. When he did so, there was a slight frown on his face.
“Well, to begin with, I think positive identification would be almost impossible. However, to go along with your assumption and with a very big if — if the material identified was in its native state and had not already been processed and separated — then I suppose one could make an educated guess about many places it might have come from. Let me put it this way: one could make a fairly good guess about where it had not been found.” He smiled apologetically for his double-talk. “These elements and their combinations are usually found in rather definite geological circumstances. I have an overall geological map of Brazil in my office, and if the mineral could be positively identified, I suppose I might be able to give you some ideas along those lines. It would be in more than one place, of course.”
Da Silva nodded thoughtfully. “I imagine you’ve traveled quite a bit in Brazil. What radioactive materials do we actually have here?”
Crandall grinned. “I haven’t traveled all that much. You have to know the expense-account procedure at the embassy to appreciate that. But I have studied the geological maps very thoroughly. To answer your question, I should say nobody knows the full extent — not just here in Brazil, but in most places in the world. For example, most people think of uranium as being very rare, although in fact it’s present in the earth’s crust to a far greater extent that such so-called common elements as cadmium, or bismuth, or silver, or even iodine or mercury. How much of it is here in Brazil? And in what combined forms?” He raised his shoulders. “That would be hard to say. Especially since large sections of the country are still unmapped.”