Rafe was nine, and he turned the quern at the bakehouse in Ellersby every morning before school. The quern was two stones standing upright in an oak frame beside the north wall. The lower stone had a dish worn into it. Furrows ran across that dish like the lines on a spread hand. The upper stone turned under his hands. He walked the handle round and round, and the wheat he had fed in came out at the bottom as flour.

Mrs Ansty gave him three rules on his first morning. Fill the eye before you start. Keep walking even when the handle feels easy. And test the meal with your hand, never with your eyes alone.

The hole in the top was the eye. The hole in the bottom was the mouth. He put a thimbleful of wheat into the eye at a time. The gap between the two stones was set by an iron peg with a head on it. The peg stood in the middle of the upper stone and went down into a hole in the frame. A wedge of wood held it there.

When the peg stood high, the stones were far apart, and the meal came out like coarse sand. When the peg sat low, the stones were close together, and the flour came out fine, like the dust off a flour sack. Mrs Ansty wanted fine flour, because fine flour makes light bread. Coarse meal makes heavy bread, and heavy bread is stale by the second day.

On the ninth morning the wedge was lying on the floor under the frame. Rafe put the peg back and tapped it down with the heel of his hand until it would not go any further. Then he ground. The meal that came out at the mouth was the colour of oatmeal, and there was grit in it. He felt that grit with his palm before anybody said a word.

A bushel of wheat weighs sixty pounds. He ground four bushels that day, which is two hundred and forty pounds, and he had carried every pound of it in from the cart.

He told Mrs Ansty at four o'clock. She put her hand into the flour and rubbed it between her thumb and her finger, then showed the two women who were waiting for their sacks. “That is coarse,” she said. “We cannot sell coarse meal as flour.” Then she gave him the test that matters. She took a pinch and squeezed it in her fist. Fine flour holds together in a lump. Coarse meal runs out of your hand like sugar.

Rafe tried it on the day's flour, and then on the flour from the sack she had kept back. The coarse one ran out. The fine one held. Mrs Ansty showed him the trough as well. Meal left standing in it overnight goes grey and sour at the edges, so the stones have to be run empty to grind that skin off before fresh wheat goes in.

They sent for Jonas Pike, who had ground at the mill up the river. He looked at the top of the peg and said the hole in the frame had been bored too wide. The peg dropped further than it should, so the stones stood too far apart. That was the whole of it. Jonas would not mend it at the forge.

He set a grindstone on the bench and dressed the top of the peg back to its old height. It took him most of an hour, and he said the wedge would hold for years. Rafe ground four bushels again that week. The flour came out pale, and it was smooth in his palm, and it held in his fist.

The bakehouse keeps a peck measure on the shelf by the door, and the poor box takes one peck in every sixteen bushels of wheat. Sixteen bushels is thirty-two pecks. One peck in thirty-two is half a peck, and half a peck is two gallons. A gallon of wheat weighs seven and a half pounds. So the box should weigh fifteen pounds, and Rafe wrote that on the tally board at the end of the week.

Then he put the flour on the little scales, and the scales said fourteen pounds and thirteen ounces, and he wrote that underneath. Mrs Ansty looked at the two numbers. The scales only read to the ounce, and nobody in a bakehouse can measure half an ounce of anything. She did not rub out either line, and both of them are still on the board, and there have been two lines on that board every week since.