The Mystery of the Memorial Day Fire

near desperation, turning back to Brian.
    “Alligation is the word the fire experts use for deep crimp marks, like alligator skin. They show up on wood at the point of origin — the place where the fire’s been set. Any natural fire would have only one point of origin. But in the basement of Mr. Roberts’s store, the investigators found six points of origin. That, in itself, is almost a sure sign of arson,” Brian said.
    “How can they possibly know that?” Trixie asked. “How can they find the points of origin of a fire that’s burned a whole building to a crisp?”
    “That’s just the thing,” Brian said. “The building wasn’t burned to a crisp, although it should have been.”
    “The arsonist’s plan failed,” Mart added.
    “How could it have gone wrong?” Trixie asked. “If you start a fire in six different places, it seems to me that it’s going to burn. It did burn. We saw it!”
    “Correction,” Brian said. “We saw it explode. That’s what went wrong. Apparently the arsonist poured a lot of flammable liquid, like gasoline, in six different places. If he’d then started the fire immediately, there would have been such total destruction from the fire that it would have been impossible to determine anything. Instead, he must have taken his time, and while he was taking his time, the liquid was evaporating, and the vapors were rising to the ceiling. When the arsonist finally lit the fire, there wasn’t much liquid to burn — but there was a lot of vapor to explode. That’s how we wound up with the big ka-boom and the traces of arson left behind.”
    “That’s fascinating!” Trixie said. “I had no idea the fire investigators could prove so much.”
    “Unfortunately, these specialists have ample opportunity to practice their profession,” Mart said. “The statistics in this sidebar are staggering. One source quoted here states that arson may cost as much as one billion dollars a year.”
    “One billion? With a b ?” Trixie asked. “As in a one followed by nine zeros?”
    “My sibling has a clearer concept of numerals than I had previously supposed,” Mart said.
    “One billion it is,” Brian told her. “I read that sidebar, too. Another source quoted says that almost forty percent of the fires that occur in this country are set deliberately.”
    “But why?” Trixie demanded. “Why would anyone want to destroy property and risk lives? Even if the buildings are insured, it’s stupid to burn them down.”
    “The perceived wisdom lies precisely in the protection afforded by insurance,” Mart said, “as you must surely realize if you ponder your prattle for a moment.”
    “Oh,” Trixie said, realizing that her statement had sounded very silly. “You mean that people would set their buildings on fire to claim the insurance on them.”
    “That’s one of the biggest reasons for arson,” Brian said. “Sometimes people over-insure a rundown building and burn it so that they get more money than they could by selling it. Sometimes people want to keep the building but remodel it. Setting a small fire in the room they want to remodel is a good way of raising the money, they think.”
    “Not all arsonists have monetary aspirations,” Mart added. “Vengeance is a motivator, as well.” Trixie shuddered. “Can you imagine hating someone so much that you’d burn down his house or his store to get even with him?”
    “I can’t imagine it,” Brian admitted. “But according to the article, people do it. Or they hire professionals to do it for them. There’s a third reason for arson, too. In spite of what Dad said the other night, some people really do love to set fires and watch them burn.”
    “Ugh!” Trixie said, shuddering again and wrinkling her nose in disgust. “That’s even worse than setting a fire for revenge! Don’t tell me any more. I think I’ve heard as much about arson as I want to know!”
    “The coverage was admirably complete,” Mart said, with a wink at his brother that Trixie didn’t see.
    “I thought so,” Brian said. “Don’t you agree, Trixie? You may not like all the information we just gave you, but you have to admit it’s pretty complete on such short notice.”
    “That is true, I suppose,” Trixie said absent-mindedly, her attention already on the comic strips.
    “Yes,” Brian continued casually, “I knew you’d agree that Jane Dix-Strauss did a first-rate job.” Trixie’s head jerked up so fast that her curls had to