Water, Stone, Heart - By Will North Page 0,42

the big stone rocked slightly.

“There's your weak spot, Burt. All it needs is trigging.”

“Triggin'?” Burt said. None of them had a clue what Jamie was talking about.

“A trig's a small stone you use as a shim, almost always on the inside of the face, like here.” Jamie poked around the stone yard and found a shard. He lifted the inside edge of Burt's stone, slipped the smaller stone beneath it, and then dropped the big one with a loud thwack.

“That's what we want to hear! Like the clack of two snooker balls when they collide. See, you have to listen to the stone. Stone will tell you when it's happy.”

Andrew saw Case lift a skeptical eyebrow. Listen to the stone. Don't look for a stone; discover it. A hedge is a space within space that wants to be filled. It was like sitting at the feet of a Zen master, Andrew thought to himself. What he'd thought would be a course about developing a new set of mechanical skills was turning into a lesson in contemplation, in the use of all your senses, not just the application of brute force.

After lunch, Jamie hauled a five-foot-tall piece of plywood out of his truck and carried it to the slowly rising hedge. It was cut in the shape of a shallow D, except that the curve of the D didn't join the vertical at the top.

“Right now, lads … and lady,” he said, bowing to Becky with exaggerated formality, “let's talk geology. Back at my place, as you saw, I've got granite wherever I look. But here on the coast, we're in a different geologic province, an older one. Here we've got slate. Slate is a metamorphic rock, which means that pressure and heat have turned it from what it was originally into something else—‘morphed it,’ as the computer types might say. Slate started out as shale, which started out as fine grains of clay and other minerals washed down from the hills into muddy deltas eons ago. As the sediments deepened, the weight exerted tremendous pressure on the layers below and changed them, hardened them. The heat and weight of the volcanic rock that came later—the granites we see up on Bodmin Moor—hardened the slates even more.

“A lot of the slate and shale in the buildings and hedges along this coast was mining waste: rock blasted loose by the old tin-mining industry hereabouts. The Delabole quarry just over the hills there, a bit west of Camelford, produces high-quality slate, for roofing tiles and such. Been operating since Elizabethan times, they have. But here we're working with rougher stuff.

“Now, there's good news and bad news in hedging with slate. The bad news is you don't get big pieces. The good news is that slate has nice, smooth parallel faces, and, if a piece is irregular, it's easy to split and dress. Slate has an obvious grain and flat cleavage planes. Of course, that's also why it busts up.

“Stacks real good, though,” Case commented.

Jamie nodded. “As our colleague, Mr. Casehill here, knows well, it's easy to build walls and houses from slate; you just slap them and stack them, like flapjacks, and mortar them together.”

Case smirked.

“But out in the fields, where most hedges get laid, you can't be fussing around with mortar. You have to come up with some other way to make the stones hold together. And that other way is called gravity.”

“Is this where the herringbone thing comes in?” Becky asked.

“Top prize to the lady!” Jamie said.

“But it's so dainty-looking,” she said.

“That's how it looks, but not how it works. How it works is like interlocking teeth, like a zipper. Tight and strong. It's all about the batter.”

“Is that like mortar?” Case asked. Burt and Newsome laughed. It was getting to be a running gag with Case.

Jamie didn't even respond. Instead, he grabbed the big piece of plywood.

“See that curve? That's what we call the ‘batter.’ A Cornish hedge curves inward, gently, and that curve creates stability. It focuses the weight of each stone toward the center. It puts gravity to work holding the whole structure in place.

“See, stones are lazy buggers,” Jamie continued. “You may have noticed this already: They don't like to be lifted. They don't like to be moved. They don't like to be stood on end. They want to lie down as soon as possible. It's not surprising; they're elderly. Their natural disposition is to be at rest, like your old granny. So your job, as a