Julius Plücker – A path from geometry to optics

This paper evaluates possible reasons and motivations for 19^th century geometer Julius Plücker's change in direction from his purely mathematical work to experimental physics. The author argues that this change did not happen suddenly in 1846 as is frequently suggested but rather, was a gradual change. This move took more than a decade and was triggered by Plücker's idea to apply his mathematical formalism to physical objects and phenomena, such as crystals and the trajectories of light in crystalline materials, a move which eventually led him to the newly discovered phenomena of diamagnetism.