The following is the entry for Henry Mangles Denham in William O'Byrnes 1849 'Naval Biographical Dictionary'.
DENHAM, F.R.S. (Capt., 1846. f-p.,37; h-p., 1.)Henry Mangles Denham was born 28 Aug. 1800.
This officer entered the Navy, in April, 1809, as a Volunteer, on board the Daphne 20, Capt. Philip Pipon, on the Guernsey and Jersey station; where he next served, from April, 1810, to May, 1814, latterly as Midshipman, in the Vulture 10, Capts. Martin White, Geo. Morris, and Henry Baugh. During the three following years we find him borne on the books of the Queen Charlotte, Boyne, and Prince, ships of the line, but detached the whole of the time on the survey of the Channel Islands, under his former Commander, Capt. Martin White; with whom, as Midshipman and Lieutenant (commission dated 26 Dec. 1822), of the Shamrock 14, he was further employed, from March, 1817, to May, 1827, in examining the English and Irish Channels, and the south-west and north-east coast of Ireland. In Oct. 1827, Mr. Denham assumed command of the Linnet 10, for the purpose of surveying the coast of France; and while nominally attached, between Sept. 1828, and March, 1835, to the St. Vincent, Caledonia, and San Josef, he conducted a survey of the Bristol Channel, and of the ports of Liverpool and Milford. As an especial mark of their approbation of the high merit and talent displayed by Lieut. Denham in the important public services which he had thus performed, the Lords of the Admiralty promoted him to the rank of Commander on the 20th of the month last mentioned. He was subsequently employed, from Jan. 1842, to July, 1845, as Commander of the Lucifer steam-vessel, and of the Royal Sovereign yacht, in defining the coasts of Lancashire and Cumberland. He was then appointed to the Avon steamer; and on 27 Sept, following he sailed on a surveying expedition to the coast of Guinea, including the mouths of the Niger. He returned to England on the attainment of his present rank, 17 Aug. 1846; and since 2 Dec. following has been borne on the books of the William and Mary yacht. Thirty years of Capt. Denham's servitude in the Navy have been employed in the construction of charts, and eighteen in the actual command of maritime surveys. In 1830 this scientific officer received the thanks and a vote of plate from the Trinity Board; in 1834 he was further presented with the freedom of the borough of Liverpool, and elected a member of the Literary and Philosophical Society at that place; and in 1830 he was chosen a Fellow of the Royal Society; as likewise, in 1841, a Younger Brother of the Trinity Corporation, and a member of the United States' National Institution for the Advancement of Science. He has received the thanks of the Geological Society, of several Refuge Harbour Committees, and of the Committee at Lloyd's.
Commander Denham, who married 18 March, 1820, has issue three sons and three daughters.