Away with imagination! Be practical! Dispense with theory! Do nothing that cannot be justified and explained to perfection. To succeed; to enjoy the wonderful practicality of the engineer-- PRESS HERE! Poltergeist Conversion Co., Ltd. Tom blinked and got the idea at once. The engineer knew. The physicist had dreamed up this thing; it must contain some sort of thing that caused the shift in personality at the physicist's will. He took hold of it and lifted. It slipped out of his fingers. He set both hands on it and lifted. It stayed on the table. He grunted and strained, and succeeded in getting it off the table by several inches. Then he gave up and returned it slowly to the top again, fearing to drop it lest it damage the desk top. Metal, huh? Must be practically solid, then. What metal? Tom thought. Must be tougher than a battleship's nose, for if entry were easy, the physicist knew he'd be rebuilding the thing every time he wanted to use it. He took a cold chisel, set the edge against one corner and walloped it with a hammer. The edge of the cold chisel turned back in a neat Vee. Tom took a file, set the cutting edge against one corner and filed. The file slipped across the corner of the box with all the bite of a solid, slick bar of smooth steel. An atomic hydrogen cutting torch stood nearby. Tom fired up and set the ultra-hot flame against the same corner that had defied his previous efforts. Nothing much happened excepting that the box got hotter. That spoiled Tom's fun for the moment. The desk below the box started to smoke and then burst into flame. Tom grabbed a carbon tetrachloride extinguisher but stopped before he played the stream on the hot metal. It was charring the desk through. The desk was ruined anyway, so Tom ignored it for the moment. He ran a bucket of water and slid it underneath the desk just in time to catch the ultra-hot box just as it passed through the table. While it was sizzling in the bucket of water and sending forth great clouds of vapor, Tom busied himself with the extinguisher, putting out the fire on the desk. Tungsten! Well, tungsten or not, it must be ruined after immersion in water after being red-hot all over. Nothing on God's green earth-- Holy entropy! He'd said that before. It presented a couple of large, bright red question marks. One. That thing was apparently tungsten clear through. Therefore, how had the physicist cast it? Two. Granted that thing had been cast--what in the name of howling rockets had the physicist used for the inside circuits? And three. If running molten tungsten into the mold hadn't ruined the guts of the box, how could heat and water do anything at all? And, disquieting thought, was the pushbutton waterproof?