In 1864 he started working on the Ordnance Survey of Jerusalem funded by the wealthy Angela Burdett-Coutts, 1st Baroness Burdett-Coutts whose primary motivation was to find better drinking water for those living in the city. During the resulting search, he produced the most accurate map of Jerusalem and identified the eponymous Wilson's Arch but was unable to find a new source of water.
In 1864, [Name] began working on the Ordnance Survey of Jerusalem, funded by Angela Burdett-Coutts, 1st Baroness Burdett-Coutts, who sought to improve drinking water access for Jerusalem's residents.  His work led to a highly accurate map of Jerusalem and the identification of Wilson's Arch, but he was unable to find a new source of water.