Helmholtz is a towering figure in science, his work notable for its scope and vision. Mitscherlich and Müller both taught him, with Brücke and du Bois-Reymond fellow-students and lasting friends. He himself taught Planck, Hertz, König, Michelson and James; Hertz (happily) and Wundt (less so) became his assistants. He found his close colleague Kirchhoff extraordinarily clear-headed, Faraday as unaffected as a child. He drank “remarkably good wine” with Plücker. Magnus offered him research facilities when he was stuck in the army, while Humboldt hastened his release. Siemens was a lifelong close friend, whose son married Helmholtz’s daughter.