Dumont d’Urville In a Frenchman's wake The zig-zagging line cutting across this close-up is the path of a ship. Standing at its helm in the hot summer of 1827 was the man who made this map the French explorer Dumont d'Urville. This tacking line shows how his vessel, the Astrolabe, regularly turned to fill its sails with wind as it moved through the sheltered channels of the Waitemata Harbour. The tiny numbers scattered across the sea are soundings, or measurements of water depth. To take each reading, the sailors on the Astrolabe had to bring the ship to a standstill then drop a weighted rope, marked with fathoms, into the water. It would have been a very stop-start voyage. Dumont d'Urville thought Auckland would make an ideal site for a French colony. With this in mind perhaps, he gave both French and Māori names to the features on this map. The body of water he named Canal de l'Astrolabe (Astrolabe Channel) is now known as Tāmaki Strait. Île Koreha, at the bottom right corner, is a French version of Motukorea, the Māori name for Browns Island.