156 MAPS AND THEIR MAKERS 



Meanwhile the land question in Ireland had created a 

 demand for maps on a larger scale which would allow the 

 areas of smaller administrative units to be shown clearly. 

 The six inch to one mile survey of that country was con- 

 sequently begun in 1824. Later, survey on this scale was 

 extended to Great Britain, and from 1840 the One Inch sheets 

 of northern England and Scotland were reductions from the 

 Six Inch. The latter is now the largest scale which gives 

 complete coverage for the whole country. 



With the industrial developments and the great expansion 

 of towns and communications in the mid-nineteenth century, 

 the demand for large-scale plans became insistent. In 1858, 

 partly under the influence of continental ideas, it was decided 

 to publish plans of the whole cultivated area on the scale of 

 1 : 2,500 (as it happens, this is very nearly equivalent to twenty- 

 five inches to one mile). The twenty-five inch is now the base 

 from which, so far as it extends, all smaller-scale maps are 

 derived. 



For many years, apart from what were essentially index 

 maps to the various series, the One Inch to a mile was the 

 smallest scale map published by the Ordnance Survey. It was 

 not until 1888 that the Quarter Inch map was completed, 

 though it had been started in 1859 at the instance of the War 

 Office and the Geological Survey. This was followed some 

 twenty years later by the Half Inch and the Ten Mile maps. 

 The demand for these in the first place was mainly military, but 

 with the development of the motor car they have become 

 increasingly popular. 



Recently, another map has been added to the national 

 series, the 1 : 25,000 (approximately two and a half inches to the 

 mile), begun in 1945. This fills usefully the gap between the 

 One Inch and the Six Inch and is a scale commonly in use on 

 the Continent. This is the smallest scale on which it is possible 

 to show roads and similar features without having to exaggerate 

 them for clarity, and to include most minor topographical 

 features. Up to date, sheets covering most of England and 

 Wales, except for central Wales, and parts of Scotland have 

 been published in a 'provisional' edition. Here provisional 

 indicates merely that it is based on the existing Six Inch survey. 



