There is a stone wall on the campus that most visitors never notice. It starts a little way behind the doghouse, where the ground begins to rise, and it runs up the side of the hill beside the path that climbs from there toward the ridge, keeping roughly to the same line for a little under half a mile before it stops at a rocky shoulder where the slope gets too steep to bother with. It is about four and a half feet high, about three feet thick at the bottom, and about half that at the top. It is gray where the weather has got at it and green where it hasn’t. Nobody knows who built it. It was there before the campus, and it will probably be there for a long while after.
It is a dry-stone wall, which means it was built without mortar. Nothing holds it together except the weight of the stones and the way they were placed. That sounds less sturdy than a wall set in cement, but it isn’t. A mortared wall is rigid, and when the ground under it shifts, as ground does over the years, it cracks. A dry-stone wall moves a little with the ground and settles back. Water runs straight through it instead of collecting behind it. When a part of it does fall, the stones are all still there, lying at its foot, ready to go back up. Some walls of this kind have been standing for several hundred years with no more care than an occasional mending.
Walls like this one were built for ordinary reasons. Fields had stones in them, and the stones had to go somewhere. Animals had to be kept in one place and out of another. Wood was scarce on high ground and stone was everywhere, so people built with stone. Over generations, in hill country in many parts of the world, this produced long lines of walls running across slopes and up over ridges, so many of them in some places that they seem to be part of the land rather than something put on top of it.
The hill wall no longer keeps anything in or out. It marks the edge of the path, gives the moss somewhere to grow, and breaks the wind a little for anyone walking up on the lee side. Once or twice a year, after a hard winter or a very wet spring, a stretch of it comes down. A length of wall that has fallen is called a gap, and the work of putting it back is called gapping. It is slow work, and not complicated, and it has hardly changed in a very long time.
The rest of this account describes that work: how a gap is taken down to sound wall, how the stones are sorted, how the foundation is set, how the two faces are built up together with the middle packed between them, how the long stones are laid across at half height, and how the top is finished. It goes in the order the work goes in. There is no hurry in it, because there is no hurry in the work.
A word about the tools, since there are so few of them. A waller needs a pair of strong gloves, a spade, a hammer for trimming the occasional stone, a set of wooden frames shaped like the end of the wall, and some string. That is nearly all. Most of the work is done by hand, and most of the skill is in looking at a stone, turning it over, and seeing where it will sit.