A key to phrenology : containing a brief statement of the faculties of the mind, the history and practical uses of phrenology / by a member of the Phrenological Society.
An 1836 Edinburgh primer on phrenology, written by an anonymous member of the Phrenological Society to explain the mind's faculties and how to read the skull for them. The plate shows four engraved views of a head, a bust, and a skull, each marked with numbered regions, arranged as a diagram for comparing cranial zones. A designer could take the numbered-grid layout and the stark engraved shading as a model for labelled anatomical or diagrammatic charts.
