John McAdam / Inventors
- Name : McAdam
- Born : 1756
- Died : 1836
- Category : Inventors
- Finest Moment : Invention of the macadam road surface
Born on 21 September 1756, in Ayr, McAdam was the son of a landowner. In 1770 he went to work in the New York countinghouse of a relative, returning in 1783 with a tidy fortune to purchase the estate of Sauchrie in Ayrshire.
Holding the post of a turnpike road trustee, McAdam was very aware of the unsatisfactory condition of roads in Britain; when it rained they quickly became very difficult or impassable. He began to experiment with various methods of road building. Acquiring the British Tar Company in 1790, it was a loss-maker to the extent that in 1795 he had to sell Sauchrie to pay off debts. He then moved to Falmouth, Cornwall, in 1798, where he was able to continue road experiments with a government appointment.
His blinding flash of insight was that if the subsoil were adequately drained, and if a 10-inch (250mm) layer of broken and graded stone chips, properly cambered, were laid on this, the effects of traffic would be not to break up the surface as before, but in fact compact the surface. In this way the macadam road surface came about, leading to a vast improvement in communications by road, not only in Britain, but in the United States.
Several sons and grandsons continued his work, designing and surfacing much of Britain's roads. He died on 26 November 1836, at Moffat, Dumfriesshire.