Measuring with a Jacob's Staff

The engraving depicts a man shown from the chest up in profile, facing left. He holds a straight, sectioned Jacob's staff (cross-staff) horizontally, with one end pressed against his eye. Dotted lines emanate from his eye, extend past the cross-piece of the staff, and widen to frame a distant cluster of trees on the left. The man has curly, textured hair and wears a simple tunic with a tie at the neckline. The background is translucent, overlaid with faint, partially visible Latin text from the page behind the illustration.

This print originates from Robert Fludd's *Utriusque Cosmi, maioris scilicet et minoris, metaphysica, physica, atque technica historia* (1617–1621), a foundational text for the Rosicrucian movement and Renaissance natural philosophy. It illustrates the application of early modern optical geometry and measurement tools to perceive the macrocosm.