John Playfair

Playfair is known, not for original discoveries, but for his clear expounding of theories (especially Hutton’s). Hutton was a close colleague — Playfair, Black and he often spending evenings together, including at the Oyster Club, where other members (and friends of Playfair) included Smith and Ferguson, whom Playfair held a joint professorship with. Playfair encouraged Somerville, investigated Edinburgh geology with Nasmyth, and met his lifelong friend Maskelyne (who got him to publish his first mathematical paper, and introduced him to London colleagues) by visiting and helping with his experimental measuring of mass at Schiehallion.