A square stone temple-like structure of Greek Doric style.
Initially proposed by the Royal Society of Edinburgh on 17 January 1820, who requested a site near Calton Hill Observatory from the Town Council - an appropriate situation as John Playfair had been President of the Astronomical Institution there. He was a distinguished mathematician and was Professor of Natural Philosophy at Edinburgh University from 1805.
W.H. Playfair the eminent architect, who was John Playfair’s nephew, designed the monument, and it was built by Smith and Cuthbertson. Completed in 1826, it is sited in the Southeast corner of the Observatory wall.
