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Notable Scots: Innovation & Discovery

James Watt (1736-1819):

Inventor & Mechanical Engineer

"James Watt... Enlarged the resources of his country[,] increased the power of man[,] and rose to an eminent place among the most illustrious followers of science and the real benefactors of the world."
~ inscription on Frances Chantrey's statue of James Watt. St. Paul's Cathedral, London
James Watt
James Watt

James Watt was born in Greenock, Renfrewshire, a seaport on the Firth of Clyde. His father was a shipwright and his well- educated mother, Agnes Muirhead, hailed from a distinguished lineage. Instead of attending school regularly, James was largely educated at home by his mother, and showed great interest in mathematics.

When Watt was eighteen, his mother passed away and his father's health began to fail. Watt traveled to London to study instrument making, but when he returned to Glasgow a year later, the Guild of Hammermen blocked his application to set up shop because he had not served a seven-year term as an apprentice. Watt was saved when professor Joseph Black from the University of Glasgow invited him to set up a small workshop within the university.

Four years after establishing his workshop, Watt, in collaboration with Black, began to experiment with steam. He toyed endlessly with the university's model Newcomen engine before coming to a critical insight: the steam, which was condensed in the cylinder by an injected stream of cold water, lost 80% of its heat to warming the cylinder. His solution was to condense the steam in a chamber separate from the piston in order to equalize both the temperatures of the injected steam and the cylinder - but he did not know how to accomplish such a task.

Watt's Steam Engine
Watt's Steam Engine

Watt's "eureka" moment suddenly came to him while he was taking a walk on Glasgow Green: he would create a vacuum in the condenser to suck the steam out of the cylinder by using an air pump. A working model was completed by 1765.

Joseph Black provided some of the capital for Watt to make a full-scale engine, for which a patent was granted in 1775. Watt then partnered with Matthew Boulton, owner of the Soho foundry near Birmingham. Their firm enjoyed great success for the next twenty-five years as they continued to make improvements to the steam engine. Watt retired in 1800 and spent his time with small inventions in his home workshop.

The improvements Watt made to the Newcomen engine, which had remained untouched for half a century, ushered in the modern industrialized western world. His name is honored with a unit of measurement for the rate of energy conversion, the watt.

Watt Memorial
Watt Memorial
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