Observing The Currents of the Straits of Gibraltar
Rare scientific sea chart, oriented with south at the top, showing the entrance to the Mediterranean through the Straits of Gibraltar, with a meticulous analysis of the currents.
The chart illustrates in great detail the fortifications on both the Iberian and African coastlines, as well as the prevailing currents,
Four tidal tables compare tide levels and times with notes on the currents, best channels for navigation, anchorages, soundings and other important navigational details. A large inset map illustrates the major shipping routes between the British Isles and Marseilles, France.
The note at the top left translates as follows:
"In this strait, the ebb and flow and the currents, even in fine weather, have many changes. The ebb and flow goes east and west, as the tables show, and when the winds are strong, they move against their opposite parts. The current flows so quickly that it seems to carry away the rocks, which are in the depth of the waters. The ebb and flow diminish in proportion to their distance from this strait into the Mediterranean Sea, and it has been observed that during a single lunar cycle, they show many irregularities, rising higher or lower at times. Experience has shown that near Malaga they become almost imperceptible. [This] indicates the ocean currents."
The map would was originally published by Beaurain, with a German copy by the Homan Heirs in about 1756.
Homann Heirs was a German publishing firm that enjoyed a major place in the European map market throughout the eighteenth century. Founded in 1702 by Johann Baptist Homann, the business passed to his son, Christoph, upon Johann’s death in 1724. Christoph died in 1730, aged only 27, and the firm was inherited by subsequent Homann heirs. This altered the name of the company, which was known as Homann Erben, or Homann heirs. The firm continued in business until 1848.