A map from Cook’s second visit to New Zealand

Chart of Resolution Harbour and Dusky Sound, on the south west of the South Island, New Zealand, drawn by Lieut. Henry Roberts (1756-796), who served with Cook on his Second and Third Voyages. Cook named Dusky Bay on his first voyage (1768-71), and returned there on his second (1772-5), spending two months exploring the fjord, planning its use as a harbour. Many of the names are still used, including Resolution Island and the unimaginative First, Second and Third Coves in Breakwater Sound. However there was a limit to their knowledge: below Third Sound is an 'Apparent Island' and, beneath that, a bay marked 'No body knows what'.

In 1791 George Vancouver, who had started his naval career as a midshipman on Cook's Second Voyage alongside Roberts, returned to Dusky Sound for re-provisioning en route to the American North West. Exploring the Sound further he reached the end of the southern bay: he could not resist adding to his map 'Somebody knows what', a joke that carried over to the published version.