The French botanist Michel Adanson spent five years in precolonial Senegal in the 1750s, under the auspices of the Compagnie des Indes. This essay follows the archival traces of Adanson’s engagement with African indigo, including experiments conducted in an ad hoc “laboratory” near the French fort of Saint Louis. A reconstruction of these experiments exposes the multifarious connections to and from the island garden-laboratory, mediated by materials and different kinds of indigo knowledge, including that of local Wolof informants. A microhistory (...) of encounters in and around a tiny island off the West African coast merges with a transatlantic story connecting Senegal to Paris and to French colonies in the Caribbean (Saint-Domingue and Guyana). The essay explores geographies of knowledge and French imperial ambitions through close attention to the material properties of indigo, the practices associated with its cultivation and transformation from plant to dye, and the material remnants of Adanson’s engagement with it in Africa. These remnants—herbarium sheets, experimental notes, color samples on paper strips, dyed fabric swatches, sketched maps, correspondence, collection catalogues, and plant taxonomies—put various kinds of African knowledge and Caribbean plantation experience into dialogue with European botany and dye chemistry. (shrink)