A chart of the Mediterranean Sea including The Gulf of Venice abd Black Sea drawn from the latest surveyes by William Heathe

Etching, printed on three-sheets, with fine later hand colour, very good condition.

Updated map of the Mediterranean Sea, first published by William Heather in 1797, here in the reprint by his pupil John William Norie.

The map belongs to the so-called "blueback charts" which began to appear in London in the second half of the 18th century; they were nautical charts of great or very large format, so named for their particular blue paper support. The media - a blue sheet commonly available and traditionally used by publishers to contain unblocked printed pamphlets - was adopted as a practical way to reinforce the low quality paper used by nautical charts publishers in an effort to reduce costs. The first known blueback cards are the ones published by Mount & Page typography around 1750 and later by Robert Sayer (1787).

Tradition took off in the early 19th century, when British publishers such as John Hamilton Moore, Robert Blachford, James Imray, William Heather, John William Norie, Charles Wilson, David Steel, RH Laurie and John Hobbs began to dominate the cartography trade boating. The bluebacks became so popular as to be adopted by the Americans Edmund March Blunt and George Eldridge, as well as by Scandinavian, French, German, Russian and Spanish cartographers. The blueback cards remained popular until the end of the 1800s, when government-subsidized organizations, such as the British Admiralty Hydrographic Office and the United States Coast Survey, began to publish their own nautical tables on high-quality paper that did not require reinforcements.

Bibliografia: J. Alexander, Loxodromes: A Rhumb Way to Go, in “Mathematics Magazine”, vol. 77, no. 5, December 2004; cfr. S. Fisher, The Blueback Charts, in “The Map Collector” n. 31, Londra 1985, pp. 18-23; S. Fisher, The Makers of the Blueback Charts, History of Imray Laurie Norie & Wilson Ltd, Londra 2001; cfr. National Maritime Museum, Catalogue of the Library - Vol. Three, Atlas & Cartography, Londra, 1971, pp. 402-414.