John Purdy (hydrographer)

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.

Before 1812 he succeeded De la Rochette as hydrographer to Messrs. Laurie & Whittle, of 53 Fleet Street, London.

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).

[5] 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 ...