Rare and important chart showing the coast either side of the Rio de la Plata estuary, marking La Citta (Buenos Aires). Sir Robert Dudley’s Dell Arcano Del Mare is renowned as the first atlas of sea charts of the world, on a uniform Mercator projection. The chart was elegantly engraved with fine calligraphy, a bold title cartouche, sailing ship and compass rose by the Florentine craftsman Arnoldo Lucini. Two sheets joined as issued. This is the second state, with "Lo.6o." added to the title cartouche.

Robert Dudley was the first Englishman to produce a sea atlas, Dell Arcano del Mare (Secrets of the Sea). Dudley, a skilled mathematician and navigator, was exiled from England and settled in Florence where his atlas was published. He introduced a totally new style for sea charts in the atlas with only lines of latitude and longitude and no rhumb lines. The charts were meticulously compiled from original sources and were both scientific and accurate for the time. This important atlas was the first sea atlas of the whole world; the first to use Mercator's projection throughout; the earliest to show the prevailing winds, currents and magnetic deviation; and the first to expound the advantages of Great Circle Sailing. In an introductory leaf found in one copy in the British Library, the engraver states that he worked on the plates in seclusion for twelve years in an obscure Tuscan village, using no less than 5,000 pounds of copper for the printing plates. It was only issued in two editions and the maps are rarely seen on the market. This map is from the second edition.

References: Shirley (BL Atlases) M.DUD-1b.

Condition: A

A sharp impression on paper with the watermark of three small hills. There is a bit of printer's ink residue at top and minor toning along the centerfold. The right margin has been extended with old paper.