ON sunnier days during the summers of the 1770s, two men and a dog might be seen climbing the slope in front of Salisbury Crags, which overlook Edinburgh from the east. They would scramble up to a level where the hard bedrock of basalt stood exposed to the open air.
We know about this from the series of sketches left by one of the pair, John Clerk of Eldin. In Penicuik, at his family’s property six miles south of the capital, they made money from coalmines, which triggered his own interest in all that lay underground. But the pursuits of the two were as much intellectual and political as economic.
