to be fine reading.'
'Thank you.' He hadn't quite thought of the article as 'fine reading' himself, but then each to his own. Dienphong's idea of fine reading was Johnson’s Rambler essays.
'The presentation is all ready,' he said, gesturing toward a double row of metal chairs set up before a projection screen. 'We're going to begin with a brief visual presentation.'
'Excellent.'
The agents seated themselves with murmurs, coughing, and scraping of chairs. Special Agent in Charge Carlton took up position in the front row center, his thick thighs spilling off the edges of the seat.
Dienphong nodded toward his assistant and the lights dimmed. He switched on the computer projector.
'Please feel free to interrupt with questions at any time.' He called up the first image. 'We'll go from simplest to most complex. This is a 50x sample of the sulfur recovered at the site. Our chemical analysis showed it to be natural, with trace elements that indicate a volcanic origin. It had been rapidly heated and burned by unknown means. When sulfur burns, it combines with oxygen to make sulfur dioxide gas, SO2, which has a very strong odor- the smell of burned matches. If it then comes in contact with water, it creates H2SO4, also known as sulfuric acid.
'These fibers here' -the next image came up-'are from the victim's clothing. Note the pitting and curling: clear effects of sulfuric acid on the victim's clothes.'
Three more images in quick succession. 'As you can see, there was even microscopic pitting on the victim's plastic glasses, and in the varnish on the walls and floor, from the intense release of sulfur compounds.'
'Any idea of the specific volcanic source?' It was Pendergast who spoke.
'That's almost impossible to answer. We'd have to analyze and compare this with thousands of known volcanic sources, an overwhelming job even if we could get the samples. What I can tell you is that the high proportion of silicon indicates a continental, as opposed to an oceanic, source. In other words, this sulfur didn't come from Hawaii or, say, the seafloor.'
Pendergast settled back, his expression unreadable in the dark room.
'This next image shows some microsections of the burned wood of the floor from the so-called hoofprint.' Several more images flashed across the screen. Dienphong cleared his throat. Here is where the difficulties began.
'You will note the very deep penetration of the burn into the wood. You can see it better at 200x.'
Another slide. 'This was not caused by a 'branding iron' effect.' He paused, swallowed. 'That is to say, this mark was not burned into the floor by a red-hot object being impressed into the wood. It was caused by an intense burst of no ionizing radiation, probably in the very short infrared wavelength range, which deeply penetrated the wood.'
Carlton spoke up, as Dienphong knew he would. 'You mean, the perp didn't heat something up and press it on the wood?'
'Exactly. Nothing actually touched the wood. The burn was made by a short blast of pure radiation.'
Carlton shifted, the chair uttering a dangerous groan. 'Wait a minute. How can that be?'
'My job is to describe, not interpret,' said Dienphong, flicking up the next slide.
But the chief hadn't finished. 'Are you saying the mark was made with some kind of ray gun ?'
'I can't say what the source of the radiation was.'
Carlton settled back with a dubious grunt.
'This brings us to the cross.' The next slide came up. 'Our art expert has identified this as a rare example of a seventeenth-century Tuscan cross, commonly worn by the noble classes. It is made of gold and silver, layered, fused, and hand-chased to produce a rather interesting effect known as llamelles fines . It was then set in wood, which has largely burned away.'
'How much's it worth?' Carlton said, asking an intelligent question for a change.
'Given the precious stones, eighty, perhaps one hundred thousand dollars. Undamaged, that is.'
Carlton whistled.
'The cross was found around the neck of the victim, touching his skin. Here is a photograph of it at the scene of the crime, still around the victim's neck.'
The next slide came up, prompting noises of disgust and disbelief.
'As you can see, the cross heated to the point of melting, deeply burning the skin where it lay. But observe that the surrounding flesh is not scorched or even reddened. Something-and I really can't say what-selectively heated the cross without heating the surrounding skin. The cross then partially melted and burned itself into the victim's flesh in situ.
'And here'-he brought up the next image-'is an electron micrograph at 3,000x, showing this extraordinary pitting along the silver-but not the gold-surface of the cross. I can't account for this, either. I suspect it might have been caused by an intense and prolonged dose of radiation that seems to have stripped off the top layers of electrons and vaporized part of the metal. It acts much more strongly on silver than on gold. Again, I have no idea why.'
Carlton was on his feet. 'Can we have this in plain English?'
'Of course,' Dienphong said dryly. 'Something heated up and melted the cross without heating up anything around it. I guess it must have been some kind of radiation that was taken up by metal more strongly than flesh.'
'Like maybe the same radiation that burned the hoofprint?'
Carlton, Dienphong had to admit, was not as stupid as he pretended to be.
