CHUCK HANNI STOOD with me and Joe in the dank basement of the building where I used to live, showing us the fine points of archaic knob-and-tube wiring as water dripped on our heads. The door to the fuse box was open, and Hanni held his Mag-Lite on a fuse he wanted me to see.

  “See how this penny is annealed to the back of the fuse?”

  I could just make out the dull copper blob.

  “The college girls on the second floor - you know them?” Hanni asked.

  “Just to wave hi.”

  “Okay, well, apparently they’ve been blowing fuses every other day with their hair dryers and air conditioner and irons and whatnot. And your super got tired of running over here to change the fuse, so he put this penny in here.”

  “Which does what?”

  Chuck explained everything that happened, how the copper penny overrode the fuse so that the circuit didn’t trip. Instead the electricity went through the penny and melted down the wiring at its weakest point. In this case, the ceiling lights on the second floor and the electric sockets in my apartment.

  I visualized flames shooting out of the socket, but I still didn’t get it - so Chuck took his time explaining to me and to Joe how my building, like a lot of old buildings, had “balloon construction,” that is, the framing timbers ran from roof to ceiling without any fire stops in between.

  “The fire just rac............