A couple of hours went by and no one came to disturb my solitude, not even to feed me. Maybe they planned to starve me out; or maybe they weren't used to being jailers and had forgotten the animals had to be fed. I had a short scrap of metal I'd worked loose from my wallet. It was mild steel, flimsy stuff, only about an inch long, but I was hoping the screw might not be set too tight. Aluminum threads strip pretty easily, so it probably wasn't cinched up too hard. There was no point in theorizing. It was dark now; I'd give it a try. I went to the window, fitted the edge of metal into the slotted screw-head, and twisted. It turned, just like that. I backed it off ten turns, twenty; it was a thick bolt with fine threads. It came free and air whooshed into the hole. The screw apparently sealed the panel after the air was evacuated. I thought it over. If I could fill the space between the panels with water and let it freeze ... quite a trick in the tropics. I might as well plan to fill it with gin and set it on fire. I was going in circles. Every idea I had started with 'if'. I needed something I could manage with the materials at hand: cloth, a box of matches, a few bits of paper. I got out a cigarette, lit up, and while the match was burning examined the hole from which I'd removed the plug. It was about three-sixteenths of an inch in diameter and an inch deep, and there was a hole near the bottom communicating with the air space between the glass panels. It was an old-fashioned method of manufacture but it seemed to have worked all right: the air was pumped out and the hole sealed with the screw. It had at any rate the advantage of being easy to service if the panel leaked. Now, with some way of pumping air _in_, I could blow out the panels.... There was no pump on the premises but I did have some chemicals: the match heads. They were old style too, like a lot of things in Peru: the strike-once-and-throw-away kind. I sat on the floor and started to work, chipping the heads off the matchsticks, collecting the dry, purplish material on a scrap of paper. Thirty-eight matches gave me a respectable sample. I packed it together, rolled it in the paper, and crimped the ends. Then I tucked the makeshift firecracker into the hole the screw had come from. Using the metal scrap I scraped at the threads of the screw, burring them. Then I started it in the hole, half a dozen turns, until it came up against the match heads. The shoes Margareta had bought me were the latest thing in Lima styles, with thin soles, pointed toes, and built-up leather heels: Bad on the feet, but just the thing to pound with. I thought about trying to work loose a piece of rug to shield my face, but decided against it. I'd have to stand aside and take my chances.