Plan d'un Marais Salant avec la description des parties qui le composent et la maniere de faire le sel

[French technical drawing] Plan d'un Marais Salant avec la description des parties qui le composent et la maniere de faire le sel, [17--. 1 sheet, ink and colour wash/ms. Drawing depicts plan and perspective of salt pans at Brouage near Marennes in western France and bears textual information, signed by Dubois, explaining both their construction and the manufacture of salt. This item is on SM b & w neg. and col. trans.]