南磁極
Seeing the consistent reduction of the crews, decimated by misfortunes, Dumont expressed his intention to leave this time for the Antarctic with "Astrolabe" only, in order to attempt to reach the South Magnetic Pole around longitude 140°. A deeply wounded Captain Jacquinot urged the hiring of a number of replacements (generally deserters from a French whaler anchored in Hobart) and convinced him to reconsider his intentions; "Astrolabe" and "Zelée" both left Hobart on 1 January 1840. Dumont's plan was very simple: to head south, wind conditions permitting.