John McAdam | Letter on road repairs by the inventor of "macadamisation", to Viscount Keith, 1819

John Loudon McAdam

Letter signed ("Jn Loudon M'Adam"), to Viscount Keith

warning that "nothing is more difficult than to put in writing the means of amending an ill made road", discussing in particular the road between Glasgow and Stirling, and the problems of inadequate surveyors and corruption, 2 pages, 4to, Muirkirk, 4 September 1819; with an enclosure entitled "Directions for road repairs", 3 pages, folio, 4 September 1819; minor wear at folds

"In repairing an old road, the safe principle to proceed upon and the most effectual, is to consider it only as a quarry. To begin and remove the materials to the side of the road, then to smooth the surface of the

natural soil giving it an inclination of One Inch in a yard from the Centre to the side..."

ADVICE ON ROAD IMPROVEMENTS BY THE INVENTOR OF "MACADAMISATION". The application of McAdam's designs of road surfaces made from convex layers of crushed stone improved the road network throughout Britain in the early 19th century. It remained influential into the time of the motor vehicle, although to prevent dust clouds the small stones need to be bound together with tar - tarmac.

PROVENANCE:

Bowood House Archive; sale, Christie's, London, 12 October 1994, lot 45