Thomas Fiott de Havilland (1775-1866) was a member of the Guernsey family at De Havilland Hall, Havilland, as well as an army officer in the East India Company and civil engineer in Madras. He served at the siege of Pondicherry in 1793 and in the campaign in Ceylon in 1795-6, and was promoted lieutenant in 1796. Under Colonel Browne in Trichinopoly, he assisted in the military maneuvers against Tipu Sultan in 1799, and accompanied Sir David Baird's troops to Egypt in 1801. He was made captain in 1806. In 1808 he married Elizabeth, daughter of Thomas Saumarez, with whom he had two daughters and two sons. In 1814 Havilland was appointed civil engineer and architect for the Madras presidency. A datum line, known as De Havilland's benchmark, was inscribed on the wall of Fort St George, in recognition of his efforts to determine the mean sea level at Madras. He also built the Mount Road, the bulwark or old sea wall of Madras, the cathedral, and St Andrew's Presbyterian Church in Madras. After his retirement, Havilland became a justice and member of the legislature in Guernsey, where he died in 1866.
From the description of Thomas Fiott De Havilland correspondence, 1799-1844. (Unknown). WorldCat record id: 702188787
