Latitude Sud. Hémisphère Occidental. – Rigobert Bonne, Atlas Encyclopédique (Paris, 1787–1788)

Monde Horizontal de latitude Sud. Hémisphère Occidental.

Rigobert Bonne (1727–1794)
From Atlas Encyclopédique, contenant la géographie ancienne...
Paris: Hôtel de Thou, 1787–1788
Copperplate Engraving on Laid Paper
Approx. 28cm x 39cm

The composition offers a sophisticated oblique projection oriented around 45° south latitude, depicting the Western Hemisphere from an uncommon southern viewpoint. It encompasses the Atlantic and Pacific Oceans, the Americas, and the South Pacific island chains, while two inset diagrams at upper and lower right illustrate the geometry of the Earth’s sphere and the projection method—reflecting Bonne’s deep concern with mathematical geography and Enlightenment precision.

How this map was made: 

Your specific map is labelled “sur un plan incliné à 45° de latitude sud” — literally, “on a plane inclined to 45° south latitude.”
That means Bonne projected the Western Hemisphere onto a tilted mathematical plane, intersecting the globe along the parallel of 45°S.

• It’s a horizontal or oblique stereographic projection, designed to represent the hemisphere as if viewed from above the South Pacific.

• The circles of latitude and longitude were computed by trigonometric formulae — not drawn freehand.

• The two small inset diagrams (top right and bottom right) demonstrate his geometric method: one shows the relationship between the sphere and the inclined plane, the other the “Sphère oblique” with the Earth’s axial tilt.

This projection was used to teach spherical geometry and astronomical navigation, it’s not just a map, it’s an Enlightenment diagram of how the Earth itself can be mathematically modelled.

Rigobert Bonne (1727–1794), one of the most important French cartographers of the late Enlightenment, served as Royal Hydrographer and Cartographer to the French Navy. His maps are celebrated for their precision, clarity, and restrained elegance marking a shift away from the decorative flourishes of earlier Baroque mapmaking toward a more scientific and empirical geography.

The Atlas Encyclopédique represents one of the most ambitious mapping projects of the 18th century, integrating ancient, medieval, and modern geography into a single comprehensive visual reference. Bonne’s engraving of Europe here captures a pivotal moment in the continent’s cartographic and political understanding just before the French Revolution, delineating the old kingdoms and maritime boundaries of the late 1700s with exceptional accuracy.

Condition:
Very good to excellent. Crisp impression with visible plate mark, wide margins, and light toning consistent with age. Minor faint offsetting in places, as expected for a fine 18th-century sheet.

Literature:
Bonne, R. & Desmarest, N. Atlas Encyclopédique, Paris: Hôtel de Thou, 1787–1788.

Collector’s Note:
Collectors prize this plate not only for its beauty but also for its didactic purpose it bridges the decorative and the scientific, embodying the intellectual ambition of late-18th-century Parisian cartography. Uncoloured impressions like ours, with strong platemark, clean paper tone, and visible watermarking, are increasingly scarce. The map’s condition and projection make it particularly appealing to collectors of Enlightenment scientific illustration and early geographic visualization.