Artillery officer and writer on all aspects of gunnery. He served in Spain 1808–1809 and 1812 and provided Southey with information for his History of the Peninsular War (1823–1832). In return, Southey tried to arrange for Douglas’s Observations on the Motives, Errors and Tendency of M. Carnot’s System of Defence (1819) to be reviewed in the Quarterly Review. Douglas was later a General and Governor of New Brunswick 1823–1831, and High Commissioner of the Ionian Islands 1835–1840.