The Empty Chair (Lincoln Rhyme 3)

Nitrates

Camphene

Rhyme stared at the charts. Finally he said, "Thom, make a call. Mel Cooper."

The aide picked up the phone, dialed from memory.

Cooper, who worked with NYPD forensics, weighed in at probably half Ben's weight. He looked like a timid actuary and he was one of the top forensic lab men in the country.

"Can you speaker me, Thom?"

A button was pushed and a moment later the soft tenor of Cooper's voice said, "Hello, Lincoln. Something tells me you're not in the hospital."

"How'd you figure that one out, Mel?"

"Didn't take much deductive reasoning. Caller ID says Paquenoke County Government Building. Delaying your operation?"

"No. Just helping out on a case here. Listen, Mel, I don't have much time and I need some information about a substance called camphene. Ever hear of it?"

"No. But hold on. I'll go into the database."

Rhyme heard frantic clicking. Cooper was also the fastest keyboarder Rhyme had ever met.

"Okay, here we go ... Interesting ..."

"I don't need interesting, Mel. I need facts."

"It's a terpene--carbon and hydrogen. Derived from plants. It used to be an ingredient in pesticides but it was banned in the early eighties. Its main use was in the late 1800s. It was used for fuel in lamps. It was state of the art at the time--replaced whale oil. Common as natural gas back then. You're trying to track down an unsub?"

"He's not an unknown subject, Mel. He's extremely known. We just can't find him. Old lamps? So trace camphene probably means that he's been hiding out someplace built in the nineteenth century."

"Likely. But there's another possibility. Says here that camphene's only present use is in fragrances."

"What sort?"

"Perfumes, aftershave and cosmetics mostly."

Rhyme considered this. "What percentage of a finished fragrance product is camphene?" he asked.

"Trace only. Parts per thousand."

Rhyme had always told his forensic teams never to be afraid to make bold deductions in analyzing the evidence. Still, he was painfully aware of the short time the two women might have to live and he felt they had only enough resources now to pursue one of these potential leads.

"We'll have to play the odds on this one," he announced. "We'll assume the camphene's from old lanterns, not fragrances, and act accordingly. Now, listen, Mel, I'm also going to be sending you a photocopy of a key. I need you to trace it."

"Easy. From a car?"

"I don't know."

"House?"

"Don't know."

"Recent?"

"No clue."

Cooper said dubiously, "May be less easy than I thought. But get it to me and I'll do what I can."