"I am, but I'm no chemist. I don't know anything about how wax burns. All I know is what it's used for, roughly, and who's in the market for it."
"Well, you know about those jumbo molecules, don't you?" I asked. "They have everything but the kitchen sink in them, including enough oxygen to sustain combustion even under water or in a vacuum. Not enough oxygen to make wax explode, like powder, but enough to keep it burning. Chemical extinguishers are all smothering agents, and you just can't smother a wax fire. And water's worse than useless."
He wanted to know why.
"Burning wax is a liquid. The melting point is around 250 degrees Centigrade. Wax ignites at 750. It has no boiling point, unless that's the burning point. Throw water on a wax fire and you get a steam explosion, just as you would if you threw it on molten metal, and that throws the fire around and spreads it."
"If it melts that far below the ignition point, wouldn't it run away before it caught fire?"
"Normally, it would. That's why I'm sure this fire was a touch-off. I think somebody planted a thermoconcentrate bomb. A thermoconcentrate flame is around 850 Centigrade; the wax would start melting and burning almost instantaneously. In any case, the fire will be at the bottom of the stacks. If it started there, melted wax would run down from above and keep the fire going, and if it started at the top, burning wax would run down and ignite what's below."
"Well, how in blazes do you put a wax fire out?" he wanted to know.
"You don't. You just pull away all the wax that hasn't caught fire yet, and then try to scatter the fire and let it burn itself out.... Here's our chance!"
All this conversation we had been screaming into each other's ears, in the midst of a pandemonium of yelling, cursing, siren howling and bell clanging; just then I saw a hole in the vertical traffic jam and edged the jeep into it, at the same time remembering that the jeep carried, and I was entitled to use, a fire siren. I added its howls to the general uproar and dropped down one level. Here a string of big manipulators were trying to get in from below, sprouting claw hooks and grapples and pusher arms in all directions. I made my siren imitate a tail-tramped tomcat a couple of times, and got in among them.
Bottom Level Broadway was a frightful mess, and I realized that we had come down right between two units of the city power plant, big mass-energy converters. The street was narrower than above, and ran for a thousand yards between ceiling-high walls, and everything was bottlenecked together. I took the jeep up till we were almost scraping the ceiling, and Murell, who had seen how the audiovisual was used, took over with it while I concentrated on inching forward. The noise was even worse down here than it had been above; we didn't attempt to talk.