1797 Carte des Déclinaisons et Inclinaisons de l’Aiguille Aimantée
DESCRIPTION
This uncommon chart of Australia, New Zeland, and New Guinea presents the region under the cartography of magnetic behavior rather than a conventional geographic survey, plotting observed values of magnetic declination and inclination across the southwestern Pacific. A regular latitude and longitude grid, referenced to the Paris meridian, structures the sheet, while numerical annotations scattered across the oceans record measured compass variation at specific points. Land is included only to anchor these readings spatially, making the sea, rather than the continents, the primary subject of the map.
The coastlines shown are intentionally partial and uneven, revealing the limits of contemporary geographic knowledge. Australia (Nouvelle Hollande) appears with a relatively well-defined eastern coast but an incomplete southern outline, while Tasmania (Terre de Diemen) is shown without full coastal closure. New Guinea (Nouvelle-Guinée) is likewise only partially delineated, with gaps and uncertainties along its shores. These omissions underscore that the map’s purpose was not to finalize coastal geography, but to situate magnetic observations within the best available outlines known to French navigators at the time.
Compiled for the Atlas du Voyage de La Pérouse and closely associated with the scientific work of Jean-Charles de Borda, using data gathered during voyages culminating in the expedition commanded by Jean-François de Galaup, the map illustrates an Enlightenment approach to cartography grounded in measurement and experiment. Its selective coastlines, sparse interior detail, and dense numerical notation make clear that this is a tool for understanding navigational forces at sea, capturing both the progress and the remaining uncertainties of late eighteenth-century exploration.
CONDITION
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