A Scottish farmer staring into ditches worked out that Earth is ancient
In 1753, James Hutton wrote that he peered with "anxious curiosity" into every pit, ditch and riverbed he passed. He was running a family farm in Berwickshire at the time, draining fields. Those muddy trenches set him thinking about how rock forms, and eventually about how enormously old the planet must be.
Hutton came to geology sideways. Born in Edinburgh in 1726, he lost his father at three, studied classics, drifted from a law apprenticeship because chemistry interested him more, and took a medical doctorate at Leiden in 1749. Back home, he and his friend John Davie learned to make sal ammoniac from soot. Until then the salt, used in dyeing, metalwork and smelling salts, had to be imported from Egypt, and their chemical works turned a healthy profit. He also inherited farms and spent the 1750s improving them with methods borrowed from elsewhere in Britain.
His friend John Playfair recalled that Hutton was in no hurry for credit. It took roughly 25 years before his Theory of the Earth reached the Royal Society of Edinburgh in 1785, read in two parts, the first by Joseph Black on 7 March and the second by Hutton himself on 4 April. Its argument was that most land was built from sediment laid down on old seabeds, hardened, and then pushed up above the ocean, while an earlier world of sea, land and living creatures had existed before it. Processes still at work, given vast stretches of time, could explain everything.
Fieldwork followed. At Glen Tilt in the Cairngorms that summer he found veins of granite cutting through schist, proof the granite had once been molten and was younger than the rock around it, against the popular view that granite settled out of water. Similar intrusions at Salisbury Crags in Edinburgh are now called Hutton's Section. Late in 1787, at Inchbonny near Jedburgh, he found near-vertical greywacke capped by flat layers of Old Red Sandstone and wrote that he rejoiced at his luck.
Hutton was a fixture of the Scottish Enlightenment, friendly with Adam Smith and David Hume, and with Black and Smith he founded a weekly Oyster Club. He helped found the Royal Society of Edinburgh in 1783. Bladder stones forced him out of the field from 1791, and he died in 1797.
Source: James Hutton
