Gother Mann (21 December 1747 – 27 March 1830) was an English army officer and military engineer in the Royal Engineers. He commanded a body of militia on Dominica when the island was captured by the French in September 1778, and his small garrison, outnumbered, surrendered on terms.
In 1781 he was employed in a tour of survey of the north-east coast of England. He was sent to North America as commanding engineer in the province of Quebec from 1785 to 1791, served under the Duke of York in Holland in 1793, and in 1794 went back to the Canadas, where he remained till 1804, when he went home to England.
He was made a colonel in 1797, colonel-commandant of his corps in 1805, lieutenant-general in 1810, and general in 1821. He was appointed inspector-general of fortifications in 1811, and held the office until death. Some of his plans for fortifying Canada are preserved in the British Library and Canada.
Early years, 1747–1771
Gother Mann, second son of Cornelius Mann and Elizabeth Gother, was born at Plumstead, Kent, on 21 December 1747. His father, a first cousin of Sir Horace Mann, went to the West Indies in 1760, and died at Saint Kitts on 9 December 1776. Gother was left under the charge of his uncle, Mr. Wilks of Faversham, Kent. After graduating from the Royal Military Academy, Woolwich, he obtained a commission as practitioner engineer and ensign in the Royal Engineers on 27 February 1763. He was employed in England on the defences of Sheerness and of the River Medway until 1775, having been promoted sub-engineer and lieutenant on 1 April 1771.
West Indies, 1775–1777
Towards the end of 1775 Mann was posted to Dominica in the West Indies and while there was promoted engineer extraordinary and captain lieutenant on 2 March 1777. In the morning of 7 September 1778, the French landed a strong force on the island, beginning a surprise invasion of Dominica. The British garrison, which was small, prepared for resistance, and Mann was named to command a detachment of the militia stationed at the new battery at Guey's Hill (now called King's Hill), which he prepared to defend. The council of the island pressured Lieutenant-governor William Stuart to capitulate; he yielded, and the island was surrendered without an effort being made to retain it.
England, 1778–1781
Mann made a report to the Board of Ordnance dated 14 September 1778, giving full details of the attack. He was only detained for a few months as a prisoner of war, and on 19 August 1779 he was appointed to the engineer staff of Great Britain, and reported on the defences of the east coast of England. He was stationed at Chatham under Colonel Hugh Debbeig. In 1781 he was selected by Lord Amherst and Sir Charles Frederick to accompany Colonel Braham, the chief engineer, on a tour of survey of the north-east coast of England, to consider what defences were desirable, as seven corporations had submitted petitions on the subject.
Quebec, 1785–1790
In 1785 Mann, age thirty-eight, was sent to the Province of Quebec as commanding engineer, succeeding William Twiss, and accompanied by fellow engineer Ralph Henry Bruyeres. Promoted captain on 16 September 1785, he was employed in every part of the country in both civil and military duties, erecting fortifications, improving ports, and laying out townships, such as Toronto and Sorel. In 1788 the governor, Guy Carleton, Lord Dorchester, had him make an extensive examination of military posts, harbours and navigable waterways from Kingston to St. Marys River, Sault Ste. Marie, in which Mann laments the ruination and ill placement of the bases: many of which were on the United States' side of the border established by the Treaty of Paris in 1783, though the British did not quit them till two years after the signing of the Jay Treaty in 1794.
Holland, 1793
Mann returned to England in 1791. He went to the Netherlands in 1792, and, joining the British army under Prince Frederick, Duke of York in June 1793, took part in the Flanders campaign. He was present at the siege of Valenciennes, which capitulated to the Coalition forces on 28 July, at the siege of Dunkirk from 24 August to 9 September, and at the battle of Hondschoote or Menin from 12 to 15 September. He was promoted lieutenant-colonel on 5 December 1793.