Keep to the discovery of lines through undoubted sighting points, as artificial mounds (including castle keeps), moats and islands in ponds or lakes. In practice churches can be treated as sighting points, but in some cases a ley passes through a tump or well close to the church. Avoid for a time the temptation of taking every bit of narrow straight road and extending it into a ley. Scrap every ley you think you have discovered if it does not pass through at least four undoubted sighting points exclusive of roads. You must use Government ordnance maps. One mile to the inch is the working scale. Other maps of two or four miles to the inch are quite useless, save for checking long leys. The (B) “Popular edition, mounted and folded in covers for the pocket,” is the most convenient for field work and is the cheapest, as it contains over double the area of the older (C) 18 x 12 edition; but I have found the latter (uncoloured, in flat sheets) necessary for transferring leys from one map to the next on drawing boards in the office. Maps cut in sections are useless for this exact work. About four drawing boards, a light 24-inch straight edge, a T square for pinning down the maps accurately to line with the boards, a moveable head T square to adjust to the angle of the ley, so as to transfer to the next map, and a box of the glass headed pins used by photographers (in addition to the usual drawing pins) are the minimum essentials for real work. A sighting compass for field work used in conjunction with a special divided quadrant on the moveable head of square are aids I have found valuable. Remember that the entire course of a ley can be found from two undoubted sighting points on it if marked on the map. Therefore stick a glass headed pin in these two points, apply the straight edge, and rule the line, pencil it at first, ink afterwards. When you get a “good ley” on the map, go over it in the field, and fragments and traces of the trackways will be found, always in straight lines, once seen recognised with greater ease in future. Where close detail is required, as in villages and towns, the 1´´scale is far too small, and the 6´´ scale is necessary. The angle of the ley is transferred to it from the 1´´ map with the aid of the moveable head square. Maps must be pinned square on the board by the T square passing through identical degree marks on the edges, latitude for leys running E. and W., but longitude for leys N. and S. The edges of the maps are not truly in line with the degree lines, and must not be the guide. Ley hunting gives a new zest to field rambles, and the knowledge of the straight ley provides new eyes to an eager observer.