One of the wonders of Harris, when Martin visited the island, was a lunar stone lying in a hole in a rock. Like the tides, it felt the moon's influence, for it advanced and retired according to the increase or decrease of that luminary. Perforated stones were formerly much esteemed as amulets. If a stone, with a hole in it, was tied to the key of a stable-door, it would prevent the witches from stealing the horses. Pre-historic relics of this kind were much used to ward off malign influences from cattle, or to cure diseases caused by the fairies. Ure, in his "History of Rutherglen and Kilbride," refers to a ring of black schistus found in a cairn in the parish of Inchinnan. It was believed to work wonderful cures. About a hundred years ago, a flat reddish stone, having notches and with two holes bored through it, was presented to the Society of Antiquaries of Scotland. It came from Islay, and had been used there as a charm. It belonged to the Stone Age, and had, doubtless, served its first possessor as a personal ornament. Ivory had magical properties attributed to it. The famous "Barbeck's Bone"--once the property of the Campbells of Barbeck, in Craignish parish, Argyllshire, and now in the National Museum of Antiquities--is a piece of ivory seven inches long, four broad, and half an inch thick. At one time it had a great reputation in the West Highlands for the cure of insanity. It was counted so valuable that, when it was lent, a deposit of one hundred pounds sterling had to be made.