John London Macadam, a Scottish engineer, born at Ayr, Sept. 21, 1756, died at Moffat, Dumfriesshire, Nov. 26, 1836. On the death of his father in 1770 he was sent to his uncle William Macadam in New York. During the revolution he was agent for the sale of prizes at the port of New York, an office in which he made a considerable fortune, the greater portion of which he lost, however, at the peace of 1783, when with the other loyalists of the city he was compelled to abandon America. He returned to Scotland in May of that year, and soon afterward purchased the estate of Sauchrie in Ayrshire. He took a prominent part in the affairs of the county, was in the commission of the peace, a trustee of the roads, and deputy lord lieutenant of the county. It was in the course of his duties as a magistrate and trustee of roads that his attention was first drawn to the subject of road making. In 1798 he was sent by the government to the west of England to regulate and remove abuses in the victualling of the navy, in which service he was kept till 1802, when he removed from Falmouth to Bristol. After 1827 he resided at Hoddesdon, Hertfordshire. From 1798 to 1815 he was engaged during all his leisure in travelling through Great Britain and investigating the condition of the roads.

In this investigation, made at his own expense, he travelled 30,000 miles and spent more than five years and £5,000. In 1811 he made a communication to a committee of the house of commons upon the state of the roads of the kingdom, containing the outlines of his system and directions for repairing roads. In 1815 he was appointed surveyor general of the trust or district of roads of Bristol, and in 1816 commenced carrying his system into operation. He met with great opposition from the farmers, traders, and common people, as well as from the employees under the old system; but after the benefits of the system became palpable, the rapidity of its adoption was remarkable. Within four years 700 miles of road in 15 different trusts were made; and within eight years he had given his personal attention and advice and assistance to no fewer than 70 trusts in 28 different counties in Great Britain. In a few years, out of the 25,600 miles of public roads in the kingdom, nearly seven tenths were macadamized; and at his death it is believed that there were not 250 miles of the whole not macadamized. (See Road.) Mr. Macadam never demanded nor received any remuneration from the various authorities, committees, and trusts by whom he was consulted, except what was freely tendered; and very many of them never even paid the expenses that they occasioned him.

In 1825 the British parliament voted him £4-,000 toward paying his expenses, and an additional sum of £2,000 as a consideration for the benefit the nation had derived from his labors and the free gift of his invention. Even this inadequate compensation was never wholly paid. He was at the same time offered knighthood, which he refused; but a similar offer was accepted by his son James, superintendent of the road district of London, who died in 1852.