Breakdown of Numbers.

This catalogue of Scottish bridges comprises all those which can be identified on any one of four ancient maps: the Military Survey of Scotland (surveyed 1747-55), John Adair’s manuscript maps (1680s), Timothy Pont's manuscripts (circa 1600) and  Joan Blaeu's Atlas Novus Vol V (published 1654).   Numerical analysis is affected by the confidence in the data.   In this context, it was not difficult to distinguish a bridge on Roy's map and to attribute it to a present location. Blaeu's atlas is very clear but orientation is often poor, and the absence of detailed contour on rivers and coasts sometimes needs an intelligent guess based on the proximity of named settlements.   This compromise is required even more when scanning Pont's manuscripts. Pont requires a great deal of interpretation: no differentiating colours or textures are used, overwriting is frequent and the maps are messy and cluttered; orientation is impossible and frequently a judgment is required as to whether or not a bridge is actually being described, far less where it is or whether it exists today.  Perhaps it is not surprising that this account of the number of bridges on Pont’s maps does not match the numbers found by one or two other researchers. 

 

Any bridge which is not on one of these four maps has not been included whether or not this might appear to be an eighteenth-century (or earlier) surveying omission.   By definition, of course, some very fine later eighteenth century bridges will be absent whilst many younger than this are included by virtue of an older predecessor at the same location.

 

There are 600 bridges in the catalogue.  Included are 44 which could be located with confidence on the map but at locations where there is no bridge today.   Further research has confirmed that 185 (30%) of the 600   are preserved: i.e. they remain structurally intact and substantially as they were in the 18th century.  Most have been given a maroon coloured marker on the OS map although those of the 16th century are given a red marker.   The remaining 413 have been given a navy marker indicating that they have been completely replaced by a more modern structure, or so extensively repaired and restructured that they no longer qualify as preserved; some no longer exist or remain only as a ruin. 

Roy divides the country by a line from Dumbarton to Stirling and the Forth Estuary. On this basis, there are more bridges in the South than in the North (335/265).  However, there are fewer 'preserved' bridges in the South (83/102).  It is clear from the distribution that there was an enthusiastic 19th century programme of replacement in the central belt, which largely accounts for the difference. The ‘preserved’ rate was 39% in the North compared to 24% in the South.  

There are 34 bridges which belong to the 16th century, both historically and architecturally. There is room for discussion about some dating features.  Most of these bridges are pre-reformation multi-arched bridges, but there are eleven single arches which belong to the same period.  Bridges in this whole group are given a red marker.  A separate list is provided.      

Eight of the bridges which are structurally pre-1600 are still taking vehicle traffic, along with a further sixty of those which have pre-1750 structure.  Most of these bridges are on very minor roads. 

There were 252  bridges on the older two maps which suggests a 16th century date.  Sixty-three of these remain today in some form that is clearly ancient.