THE initiation of an entirely new ordnance map series on a scale of 1: 25,000, or about 2 ½ inches to the mile, was one of the chief recommendations of a departmental committee set up in 1935. It was felt that the gap between the 1-inch and 6-inch was too wide for many users. In the areas already covered there are signs that the new scale is growing in popularity. Some five hundred sheets, or about one fifth of the projected total, are now published, and it is hoped that the remainder will be ready in about three years time. The new map is based on the old six-inch map, to which has been added certain revisions made for war purposes. In this sense only is it provisional : the final edition will incorporate 50-in. re-surveys of built-up areas, now in hajid in many towns, and an overhaul of 25-in. plans in rural areas. The sheet edges lie along the 10 kilometre grid lines of the national grid, and each sheet is known by the 10 km. grid reference of its south-west corner. The new map is sold in three styles, the fully coloured, the outline and the administrative areas. In the first, contours and main roads are in brown, water in blue, black for outlines of roads, buildings and railways, and solid black for public buildings. The outline edition is in grey monochrome without contours and is printed on specially heavy paper suitable for drawing offices. The administrative areas edition has all such boundaries shown by a red overprint on the outline edition ; apparently it is being considered whether or not to continue the production of this edition. The following areas are now in the course of being covered by the 1 : 25,000 map: Greater London, Edinburgh, Glasgow, Dundee and Aberdeen; Plymouth and Dartmoor ; Purbeck, New Forest, Southampton and Portsmouth, and most of the south coast; South Wales and Bristol ; Gloucester, Oxford, Reading and Luton; East Anglia and the Broads; Birmingham and district; Tyneside and Lancashire, Yorkshire and Cheshire. These maps, with the 6-in. to the mile, are known as ‘medium scale'. Full descriptions of other Ordnance Survey maps, with illustrations and indexes, are given in two pamphlets, one dealing with small-scale maps and the other large-scale maps, issued by the Director General, Ordnance Survey Office, Chessington, Surrey (Is. 6d. each).