"It was the worst one," Eli admitted. Thomas studied the page a little longer, then closed the notebook and placed it on the table between them. "You know," he said, "if I'd been willing to write down my mistakes at fourteen, your grandfather might have saved himself a great deal of trouble teaching me." Eli looked at him, unsure how to answer, and Thomas pushed the notebook back with a small smile.
The following evening, Old Mr. Henderson appeared at the barn door carrying a bent pair of pliers. He said he needed a different tool for his gate, though Thomas knew perfectly well the old man owned at least three suitable pairs. Thomas sent Eli to fetch the toolbox, then watched Henderson wander almost casually toward the pear tree. The older farmer stopped at the strip, leaned on his cane, and examined the stones in silence.
"This is what they're making all the noise about?" Henderson asked without turning. Eli came to stand beside him and nodded. Henderson crouched slowly, groaning once as his knees folded, and lifted a pale flat stone just enough to see the earth beneath. His face changed, losing the faint amusement it had carried since his arrival.
"Well, I'll be," he murmured. He moved to a neighboring patch, examined the exposed soil, and compared it with the darker ground beneath the stones. The old man stayed so long that Thomas finally came to ask whether he had found a tool or intended to move in. Henderson ignored the joke and asked Eli who had taught him to use stone mulch.
The words made the boy blink. "Stone what?" he asked. Henderson held a piece of soil between his fingers and explained that some farmers in dry climates had used loose stone coverings for generations to reduce evaporation and protect fragile ground. He had read about similar methods in an old agricultural book years before, though he had never tried one on his own fields. "It's not a way to make rain," he warned, "but it can sometimes help you keep the rain you get."
Eli felt as though someone had opened a window in a room where he had been working in the dark. The arrangement was not a foolish invention peculiar to him, and other people had spent time thinking about the same problem. He asked whether stones could also make soil too hot. Henderson nodded at once and said the effect depended on the kind of rock, the arrangement, the season, and the water beneath it.
"Some places it'll help, some places it'll do little, and some places you'll make a mess," the farmer told him. "That's why your little test is worth more than a hundred speeches about the idea." He examined the shallow channels and the open spaces around the bean stems, then asked who had suggested those. When Eli described the first runoff failure, Henderson nodded as though hearing about a familiar mistake he had made himself in a different form.