C18th object drawn by Philippe Simmoneau. Amateur translation of the title: “Tree of Iron or Red Iron Vitriol”
This image illustrates a report by L. Lemery le Fils (1677-1743) on the presence of iron in plants. Lemery presents his research on “les cendres de castoreum dont les grains sont attiré par l’aimant.” (Ashes of castoreum, particles of which are attracted by magnet). The castoreum referred to is evidently a plant, not the preputial follicles of the beaver used in perfumery (below left).

The plant in question one assumes, is the castor bean plant, Ricinus, (above right) from which the purgative castor oil and the poison ricin are derived. Lemery describes putting the ashes and sulfuric acid in a pot moistened with water and the flakes of acid-charged iron rising from the ashes like a living thing.