Duncan began his sea life in the merchant service, possibly in that of the
East India Company, but entered the
Royal Navy on in 1755 joining . Duncan later joined . On 3 January 1759, Duncan passed his examination for lieutenant and joined . Duncan then joined
HMS Prince in
Gibraltar, but was soon transferred to and then . He married Mary French in
Dartmouth, on 27 November 1761. He participated in the capture of
Havana in 1762 and was moved to . During this time he had two children, Isabella (born 23 August 1764) and Arthur French (born 9 February 1769). Duncan already had an older son, Henry, who later served in the Navy from 1781 until being lost off the coast of
Newfoundland in 1802 with
HMS Scout. On 26 May 1768, Duncan was promoted to
commander and joined . Soon after he was promoted to
captain. In January, 1776,
William Howe was appointed as
Commander-in-Chief of British forces in North America and chose Duncan to join him as
flag captain of . His career in North America lasted for the next six to seven years. On the commands of General Howe, Duncan commanded an invasion fleet of 26 ships carrying 2,000 men led by General
William Tryon from New York to
Westport, Connecticut, to raid Continental Army supply depots in
Danbury, Connecticut, on 22 April 1777, resulting in the
Battle of Ridgefield. Duncan later returned to Europe to participate in the
relief of Gibraltar in 1781. He was appointed Commissioner at Halifax. He participated in the
North British Society. He was appointed to the
Nova Scotia Council in 1788, resigning in 1801. Duncan remained at Halifax until 1799, when he returned to England, to be appointed Commissioner at
Sheerness, and
Deputy-Comptroller of the Navy in January, 1801. He retired from the post in 1806 and resided at Dartmouth until his death on 7 October 1814. His widow Mary survived until 25 September 1823. == Notes ==