[1] He was employed as a naval officer by the East India Company, a midshipman in 1811, becoming a commander in 1827 on the Marchioness of Ely.
[2] In 1831 he left the service of the East India Company, in order to marry, and joined his elder brother Frederick, who had taken over their father's business, as a partner.
[5] Mangles acquired the Poyle Park estate near Farnham, Surrey, by purchase, under the terms of the will of his father.
[8] Active in promoting the Victoria Dock for London by Act of Parliament (1850), he worked with Edward Ladd Betts, Samuel Morton Peto, and another banker, J. P.
Charles Bradlaugh brought an action against the English Joint-Stock Bank, for unpaid commission.