John Purdy (1773–1843) was an important English

hydrographer Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers, as well as with the prediction of their change over time, for the primary ...

. His work and influence extended beyond hydrography with the coinage of the term pharology, the study of modern lighthouses and their designs. Purdy's work ''Memoir, descriptive and explanatory, to accompany the New Chart of the Atlantic Ocean'' was adapted and improved; continuing to be released in its fifteenth edition fifty years after his death.

Life

The son of a bookseller at

Norwich Norwich () is a cathedral city and district of the county of Norfolk, England, of which it is the county town. It lies by the River Wensum, about north-east of London, north of Ipswich and east of Peterborough. The population of the Norwich ...

, Purdy took up the study of naval charts and similar subjects. Before 1812 he succeeded De la Rochette as hydrographer to Messrs. Laurie & Whittle, of 53

Fleet Street Fleet Street is a street in Central London, England. It runs west to east from Temple Bar, London, Temple Bar at the boundary of the City of London, Cities of London and City of Westminster, Westminster to Ludgate Circus at the site of the Lo ...

, London. Purdy does not seem to have taken part in hydrographic expeditions himself, and his work consisted in writing works and constructing charts based upon the reports of others; but eventually he became a leading authority of his time on hydrography. He was mainly instrumental in bringing '' Rennell's Current'' before the notice of navigators, and in 1832

James Rennell Major (United Kingdom), Major James Rennell (3 December 1742 – 29 March 1830) was an English geographer, historian and a pioneer of oceanography. Rennell produced some of the first accurate maps of Bengal at one inch to five miles as well as a ...

's daughter, Lady Rodd, asked Purdy to edit his ''Wind and Current Charts''. Purdy died on 29 January 1843.

Works

In 1812 Purdy published a ''Memoir, descriptive and explanatory, to accompany the New Chart of the Atlantic Ocean''. This work went through many editions, the fifteenth appearing in 1894, edited by William Kettle, F.R.G.S.; Kettle was a nephew of

Alexander George Findlay Alexander George Findlay (1812–1875) was an English geographer and hydrographer. His services to geography have been compared with those of Aaron Arrowsmith and August Heinrich Petermann. Life Findlay was born in London, 6 January 1812, a ...

, who succeeded Purdy as a leading hydrographer, edited and improved many of Purdy's works, and took over the firm of Laurie & Whittle. Among Purdy's other major publications were: *''Tables of Positions, or of the Latitudes and Longitudes of Places'', 1816. *''The Columbian Navigator'', 1817; other editions 1823–4, 2 vols., 1839, and 1847–8. *''Memoir to accompany the General Chart of the Northern Ocean'', 1820. *''The New Sailing Directory for the Ethiopic or Southern Atlantic Ocean'', 1837; 3rd edit. Findlay, 1844. Similar ''Sailing Directories'', dealing with many other regions, were also published by Purdy. *''The British American Navigator'', 2nd edit. 1843. A list of Purdy's maps and charts was given in the ''Catalogue of the Map Room of the Royal Geographical Society''. They include: a chart of the Atlantic Ocean (1812); a ''map of Cabotia, comprehending the Provinces of Upper and Lower Canada'', (1814); a map of the world on Mercator's Projection (1825); The Azores (1831); Jamaica (1834); the Viceroyalty of Canada (1838); Newfoundland (1844). Others published by Findlay, after Purdy's death, include the Indian and Pacific Oceans (1847); St. George's Channel (1850); the coasts of Spain and Portugal (1856). His nephew Isaac published a chart of the coasts of China in 1865.

Lighthouses

Purdy is credited as the coiner of the word " Pharology" as the study of modern lighthouses from the 1800s. The word appeared in Purdy's 1839 ''The Colombian Navigator; Or, Sailing Directory for the American Coasts and the West-Indies''. The following year, 1840, it was used in Purdy's ''The New Sailing Directory for the Strait of Gibraltar and the Western Division of the Mediterranean Sea: Comprehending the Coasts of Spain, France, and Italy, from Cape Trafalgar to Cape Spartivento, the Balearic Isles, Corsica, Sardinia, Sicily and the Maltese Islands, with the African Coast, from Tangier to Tripoli, Inclusive ... Improved, by Considerable Additions, to the Present Times''.

Notes

;Attribution {{DEFAULTSORT:Purdy, John English hydrographers English cartographers English topographers 1773 births 1843 deaths 19th-century English scientists 19th-century English people 19th-century British cartographers