born Sept. 21, 1756, Ayr, Ayrshire, Scot.
died Nov. 26, 1836, Moffat, Dumfriesshire
Scottish inventor of the macadam road surface.
He made an early fortune in his uncle's New York countinghouse (1770–83). Back in Scotland, he noted the poor condition of the highways near his estate and undertook experiments in road making. He recommended that roads be raised above the adjacent ground for good drainage and covered, first with larger stones and then with smaller stones, the whole mass to be bound with fine gravel or slag. In 1823 his views were officially adopted, and in 1827 he was appointed Britain's Surveyor General of Metropolitan Roads. Macadamization was quickly adopted in other countries and did much to facilitate travel and communication.