John Loudon McAdam

John Loudon McAdam (23 September 1756 – 26 November 1836) was a Scottish civil engineer and road-builder. He invented a new process, "macadamisation", for building roads with a smooth hard surface, using controlled materials of mixed particle size and predetermined structure, that would be more durable and less muddy than soil-based tracks.

Modern road construction still reflects McAdam's influence. Of subsequent improvements, the most significant was the introduction of tar (originally coal tar) to bind the road surface's stones together, "tarmac" (for Tar Macadam.)

Early life

McAdam was born in Ayr, Scotland. He was the youngest of ten children and second son of the Baron of Waterhead. He moved to Lagwine at Carsphairn when still a child to live with his grandparents. The family name was traditionally McGregor, but was changed to McAdam (claiming descent from the Biblical Adam) for political reasons in James VI's reign.

He moved to New York in 1770 and, as a merchant and prize agent during the American Revolution, made his fortune working at his uncle William McAdam's counting house. He returned to Scotland in 1783 and purchased an estate at Sauchrie, Ayrshire.

Besides taking part in local Ayrshire affairs, McAdam operated the Kaims Colliery. The colliery supplied coal to the British Tar Company, of Archibald Cochrane, 9th Earl of Dundonald, and partners in the coal tar trade; McAdam ran its kilns. He further was involved in the ironworks at Muirkirk, which was a customer for the coke byproduct of the tar business. This business connection is the only direct relationship of McAdam and tar.