So Arvo Kivisto took her down. He went down the wooden stairs ahead of her in the dark, without the flashlight, touching the rail, counting under his breath in Finnish, and when they got to the bottom he went straight across the boiler room to the little copper pipe on the floor and crouched and put his big hand on the wheel of the valve, on the stripe of white paint, without feeling for it, the way you'd put your hand on your own knee.
"Look at the glass," he said. "Tell me where it is."
"A little under half. A third, maybe."
"So. Open this one quarter turn. Only a quarter. Listen." He turned it, and she heard the water hiss in the pipe. "Now watch the glass. When it comes to the half, you close it. Not more than half. Too much is no good either; she'll throw water up the pipes and they knock. You must watch, every time, before you do anything else. Before the fire, before the coal. First the glass. Johanna always said. First the glass, then the fire."
She watched the glass. The water in it rose, so slowly that at first she wasn't sure it was moving, a dark line climbing against a white card someone had wired behind the tube with a pencil line on it at the middle. When it touched the pencil line, she said, "Now," and Arvo turned the wheel back and the hiss stopped.
"Good," he said. "You see? Easy."
"What if it's empty?"
Arvo turned his white eyes toward her. In the orange light from the fire door his face was all hollows.
"Then you don't touch it," he said. "Then you don't touch it ever. If the glass is empty, the iron is dry inside, and if the iron is dry and the fire is under it, the iron gets hot, very hot, red hot maybe. And if you put cold water on red-hot cast iron..." He took his hand off the valve and opened it in the air, all five fingers, slowly. "Then the boiler is in the lobby and we are in the alley. Or the other way. Johanna's husband's father was killed that way, in Cornwall, in a mine engine house. She told me once. That is why she is like this about the glass."