Francis Buchanan (15 February 1762 – 15 June 1829), later known as Francis Hamilton but often referred to as Francis Buchanan-Hamilton was a Scottish physician who made significant contributions as a geographer, zoologist, and botanist while living in India.
The standard botanical author abbreviation Buch.-Ham. is applied to plants and animals he described, though today the form "Hamilton, 1822" is more usually seen in ichthyology and is preferred by Fishbase.
He was born Francis Buchanan at Bardowie, Callander, Perthshire; his family originated in Spittal[disambiguation needed] and claimed the chiefdom of the name of Buchanan. Francis studied medicine at the University of Edinburgh. After several voyages on Merchant Navy ships to Asia, he served in the Bengal Medical Service from 1794 to 1815. He also studied botany under John Hope in Edinburgh.
Career in India
In 1799, after the defeat of Tippu Sultan and the fall of Mysore, he was asked to survey South India resulting in A Journey from Madras through the Countries of Mysore, Canara and Malabar (1807). He also wrote An Account of the Kingdom of Nepal (1819).
He conducted two surveys, the first of Mysore in 1800 and the second of Bengal in 1807-14. From 1803 to 1804 he was surgeon to the Governor General of India Lord Wellesley in Calcutta, where he also organized a zoo that was to become the Calcutta Alipore Zoo. In 1804, he was in charge of the newly founded 'Institution for Promoting the Natural History of India' at Barrackpore.
From 1807 to 1814, under the instructions of the government of Bengal, he made a comprehensive survey of the areas within the jurisdiction of the British East India Company. He was asked to report on topography, history, antiquities, the condition of the inhabitants, religion, natural productions (particularly fisheries, forests, mines, and quarries), agriculture (covering vegetables, implements, manure, floods, domestic animals, fences, farms, and landed property, fine and common arts, and commerce (exports and imports, weights and measures, and conveyance of goods). His conclusions are reported in a series of treatises that are retained in major United Kingdom libraries; many have been re-issued in modern editions. They include an important work on Indian fish species, entitled An account of the fishes found in the river Ganges and its branches (1822), which describes over 100 species not formerly recognised scientifically.
He also collected and described many new plants in the region, and collected a series of watercolours of Indian and Nepalese plants and animals, probably painted by Indian artists, which are now in the library of the Linnean Society of London 
He succeeded William Roxburgh to become the Superintendent of the Calcutta botanical garden in 1814, but had to return to Britain in 1815 due to his ill health. In an interesting incident the notes that he took of Hope's botany lectures in 1780 were lent to his shipmate Alexander Boswell during a voyage in 1785. Boswell, lost the notes in Satyamangalam in Mysore and the notes went into the hands of Tipu Sultan who had them rebound. In 1800 they were found in Tippu's library by a major who returned them to Buchanan.
Buchanan left India in 1815, and in the same year inherited his mother's estate and in consequence took her surname of Hamilton, referring to himself as "Francis Hamilton, formerly Buchanan" or simply "Francis Hamilton". However he is variously referred to by others as "Buchanan-Hamilton", "Francis Hamilton Buchanan" or "Francis Buchanan Hamilton".
- Vicziany, Marika (1986). "Imperialism, Botany and Statistics in Early Nineteenth-Century India: The Surveys of Francis Buchanan (1762-1829)". Modern Asian Studies 20 (4): 625–660.
- Buchanan, Francis (1807). A Journey from Madras through the Countries of Mysore, Canara and Malabar. London: T. Cadell & W. Davies / Black, Parry & Kingsbury. – in three volumes, publishers noted as booksellers to the Asiatic Society and the East India Company, respectively.
- Noltie, H.J. (1999) Indian botanical drawings 1793–1868. ISBN 1-872291-23-6