These rather early thematic maps depict the wind currents across the world's major shipping routes, showing the world on an unusual oval projection. Both maps are centered on the equator and depict the currents by means of engraved directional lines. The trade winds are shown with little arrows, augmented with the names of months. The first map focuses on the Pacific and shows a portion of North America with the island of California and partial coastlines for Australia. The second map displays the winds across the Atlantic and Indian Oceans. This pair of matched maps was engraved by Cosmant. Most of the maps in Prevost's work are by Jacques Nicolas Bellin, but these maps do not contain any attribution.

References: Mickwitz & Miekkavaara (Nordenskiold-3) #638, vol. XI, map 9 & 10.

Condition: B+

Nice clean impression with some minor toning primarily in the blank margins. The map of the western hemisphere has a unobtrusive repaired tear on verso in the upper-right portion of the image. Issued folded.