Dell'arcano del mare [Books 1-4]. Robert Dudley1573-1649. Firenze: Francesco Onofri, 1646. 2 volumes [of an eventual 3] in one. Folio (13 x 9 4/8 inches). Half-title, title-page dated 1646, with fine engraved vignette of a compass (without half-title and title-page to volume 2, ie Books 3-4, and errata leaf at end, dampstaining to half-title, title-page and folding engraved patent plate, some minor and occasional spotting), folding engraved facsimile of the patent of nobility granted to Dudley in 1620 by Ferdinand II, 15 engraved folding charts in Book 2, including 5 double-sheet, and 66 (of 69) engraved plates by Antonio Francesco Lucini, various sizes, 49 folding, the plates variously numbered (see Phillips), , including 30 plates of astronomical or nautical instrument designs with volvelles, pointers or string-pointers, 7 double-sheet plates of diagrams of ship-building in Book 4, and one very small engraved diagram pasted down in lower margin of folio I2 in Book 4, four plates in Book 1 with letterpress text on versos, 5 inserted unnumbered leaves in Book 3 containing 10 letterpress diagrams of naval formations (without 2 plates in volume one, and one folding plate in Book 4, three plates with tears near the gutter, map of the Americas with small tear at fold juncture, a few of the double-sheet maps slightly browned along sheet junctures from original paste, else EXCEPTIONALLY FINE). Contemporary vellum, manuscript title on spine, edges stained red (a bit creased, especially at the extremities, and with a few pale stains, pastedowns torn). Provenance: with the near contemporary ownership inscription of the library of the Colegio Mayore Cuenca in Salamanca ("En la libreria del Colegio . Cuenca") on the title-page, numbering to the plates, and extensive underscoring and a few marginal notes in red pencil throughout. "THE ONLY EXCEPTION TO THE TOTAL DOMINANCE OF DUTCH SEA ATLAS PRODUCTION." (Burden) First edition of Books 1-4 of an eventual 6 (Books 5 and 6 being published later because the European charts needed updating). Dudley's great, and rare, sea-atlas "Dell' Arcano del Mare" or "Secrets of the Sea", is the first sea-atlas compiled by an Englishman, the first atlas to show the charts constructed on the Mercator projection, the first to show prevailing winds and currents in the principal harbors, and the first to give magnetic declination. The 15 maps in book 2 consist of large-scale maps of the four continents; five relate to the Americas, including "Carta prima Generale d'America." of Central America and Peru with a detailed inset showing the Californian coast, which is the first printed sea chart of the west coast of North America (Burden 266), and "Carta seconda Generale del' America." of the eastern seaboard that is the first printed sea chart by an Englishman of the eastern North American coast, as well as the first to methodically record soundings. The soundings in Chesapeake Bay are recorded only here: they are "curiously lacking in the more detailed chart published in the sixth part... The most interesting area is that of New York where any indication of the Dutch presence is removed" (Burden 267). The Hudson River is named in deference to its discoverer, rather than the Dutch "Noort River". In the dedicatory epistle to the second edition of 1661 the engraver Lucini stated 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 in the making" (Phillips). The sources for Dudley's maps were clearly wide and varied, his position in society gave him admission to many quarters, and it has been proposed that these include his cousin Thomas Cavendish (the third circumnavigator of the world), it has even been suggested that Dudley had access to Henry Hudson's notes, and Sir Francis Drake's papers, although it is more likely that the charts of John Daniell, that still reside in Florence were the source for the important "Carta prima Generale d'America." Phillips 457; Burden 266-267; Nordenskiöld Collection, 7. Guidance: Sotheby’s, 1988 - £ 48,400 GBP