or Bunon, the name of an ancient species of building, of a circular form, common in the Orkney and Zetland Islands, the Hebrides, and the northern parts of Scotland. The latter term indicates the founders, who at the same time bestowed on them their native name of borg, a Sugo-Gothic word signifying a defence or castle; and the Highlanders universally apply to these places the Celtic name dun, signifying a hill—a term easily transferred to the tower itself by which a hill was usually defended. They are confined to the countries once subject to the crown of Norway. With few exceptions, they are built within sight of the sea, and several of them within sight of each other; so that, on a signal by fire, by flag, or by trumpet, they could give notice of approaching danger, and afford mutual support. In the Orkney and Zetland Islands they are most frequently called wort or ward hills, which shows that they were garrisoned. They had their wardmuther, or watchman, a sort of sentinel, who stood on the top, and challenged all who came in sight. The gackman was an officer of the same kind, who not only had to watch against surprise, but was also bound to give notice if he saw any ships in distress. He was allowed a large horn of generous liquor, which he had always by him, to keep up his spirits. Along the Orkney and Zetland shores they almost formed a chain, and by that means not only kept the natives in subjection, but were situated commodiously for covering the landing of their countrymen, who were perpetually roving on piratical expeditions. These towers were even made use of as state prisons; for we learn from Toricus, that after Sueno had surprised Paul, count of Caithness, he carried him into Sutherland, and confined him there in a Norwegian tower. Out of this kingdom no buildings similar to these are to be found anywhere, except in Scandinavia. On the mountain of Swanhberg in Norway is one; on the Stir-biskop, at Upsal, in Sweden, is another; and on Umshorg, in the same kingdom, is a third.

These towers vary in their inner structure, but externally they are universally the same, though some have an addition of strength on the outside. The burgh of Culswick, in Zetland, notwithstanding it is built on the top of a hill, is surrounded with a dry ditch 13 feet broad; that of Snaburgh, in Unst, has both a wet and a dry ditch, the first being cut with great labour through the solid rock. The burgh of Moura is surrounded by a wall, now reduced to a heap of stones, and the inside is cylindrical, not tapering, as is usual with others. The burgh of Hogster, upon an isle in a loch of the same name, has also the addition of a wall; a peculiarity in a causeway to join it to the mainland, and a singular internal structure. Numbers of little burghs, with single cells, are scattered about in the neighbourhood of the greater, and were probably built by the poorer sort of people, in order to enjoy their protection. A multitude of places in these islands have the addition of burgh to their names, notwithstanding there is not a vestige of a tower near them, the materials having long since been carried away and applied to various uses.