[AUSTRALIA-NSW] Port Jackson

The first issue of this important Hydrographic chart of Port Jackson dated 11th February, 1857 surveyed by Captain Henry Mangles Denham. Shown are soundings, details of streets and large residences of the harbour side suburbs. At lower left is an inset of The Heads and along the bottom of the map is a coastal profile from the sea, titled; Port Jackson Entrance.

This first issue of the map is identified by placement of the title which is positioned closer to the centre and the lack of an inset of North and Middle Harbour which appears at the top in later editions.

On 18 February , 1852 Denham was appointed commander of H.M.S. Herald and sailed for Port Jackson on June 9, arriving on February 19, 1853. His arrival marks a distinct change in Admiralty policy in Australian marine surveys in the use of more scientifically young surveyors rather than the explorer surveyors of earlier days. During his nine years in Australian waters Denham completed surveys totalling 200 sheets of charts and drawings. He observed 163 geographic positions, and obtained the variation of the compass, 2410 times afloat and 191 times on shore. He contoured over 700 miles of edge of soundings and erased from charts twenty-three fabulous dangers, or vigias-reported shoals, the existence of which had previously been doubtful. While the Herald was at Port Jackson undergoing a refit, her officers completed a thorough survey of the harbour. This Admiralty chart was the result of this survey and superseded the earlier charts by John Septimus Roe and Owen Stanley. Denham was assisted in this new survey of the Harbour by Lieutenant J. Hutchinson, J.H. Smith, E. Wilds, masters, and F. Howard and F. Hixon.

The regular updating of Hydrographic charts by the Hydrographic Office was to ensure that Commanders of ships, pilots and other mariners were able to have the most to date information available to safely navigate foreign waters and ports as new information of changes to sea depths, sand bars, wrecks or other any other pertinent nautical information that could hinder passage became available. As updated charts were offered for sale, the earlier outdated charts in the hands of mariners, pilots, ships owners and sailors were invariably discarded, subsequently making all British Admiralty issued hydrographic charts of the period rare but especially the first issues.