James Watt, the steam engine, and the day Scotland started to change the world

Steam engines had already existed since 1712, but only of a rudimentary kind. The first standard model was the Newcomen engine, named after its inventor Thomas Newcomen. It was used mainly to pump water out of coal or tin mines in the south-west of England.

Probably the earliest to arrive in Scotland belonged to the progressive Jacobite George Lockhart of Carnwath at his estate of Dryden in Midlothian. It had big drawbacks. It could only be used on one site and was not portable. The equipment remained notoriously unsound and had poor fuel efficiency dependent on large quantities of coal.

The operator of a Newcomen engine needed ready access not only to the various raw materials but also to cash, always short in Scotland in the first decades of the Union. Progressive entrepreneurs often ran into financial trouble. It was a hazard that could affect established landed families, not just those over-confident of their business acumen. Scotland was also a pioneer of banking and even banks went bust too.

READ MORE: The Scottish innovation that changed banking forever

There were more modest families such as the Watts with at least a sound financial basis built up on local success, in their case at Greenock.

They were strong Presbyterians with a history of devotion to the Scottish Covenants. Thomas Watt, grandfather of James, was besides a teacher of mathematics, surveying and navigation. In the next generation another James rose in the public life, such as it was, of the busy wee burgh and became its chief bailie in 1751.

James senior had higher ambitions still, ambitions on an international scale. He started trading to the West Indies in slaves and in slave-produced goods. Recent researches have shown he would involve his inventor son James in this business, too. It is already known how vital slavery was to the fortunes of the commercial elite of enlightened Scotland. Evidently, the Watts considered themselves part of this elite.

James Watt the younger was the most vital of all. Without a radical improvement in the power, efficiency and cost-effectiveness of steam engines, as they had so far existed in the 18th century, there could never have been enough progress in Scottish industry. There had to be a breakthrough of some kind. That was the work of Watt.

Watt was born at Greenock in 1736, the son of the shipwright and shipowner, and chief bailie of the busy harbour at a time when seagoing vessels could not get any further up the River Clyde.

Hanging round his father’s workshops, the lad started fashioning mathematical instruments. This was not always with the approval of the social-climbing parent, who disapproved of his “insolence, sauciness and disobedience” and would have preferred him to master Latin and Greek.

Luckily, the younger James took no notice at all and by the age of 21 he had landed a good job supplying his mathematical instruments to the University of Glasgow. He had no other way to use his skills in the city because he was not allowed into its merchant guild. That was the way Scotland worked in pre-industrial times. Watt’s patent No 913 guaranteed him the legal rights of the inventor whatever the local merchants might say.

It was one of the most important documents in Scottish history. Like the Declaration of Arbroath in the 14th century or the Confession of Faith in the 16th century, the patent changed the face of the country.

This was not because it actually invented the steam engine, as keen schoolmasters used to claim to their pupils, but because it was the decisive improvement of the Newcomen engine. For that reason Watt is rightly credited with being the father of the steam power that drove the Industrial Revolution.

Watt was never satisfied but constantly sought improvements in the technology of steam engines. In fact, he spent years of experiment on a system with a chamber, separate from the main piston, where the steam could be condensed. He realised that existing designs wasted too much energy by repeatedly cooling and reheating the cylinder. His improved designs relied on a separate condenser to cut out the excessive waste.

There was a further major improvement when eventually Watt adapted his engine to produce rotary motion. This allowed its use to be broadened far beyond pumping water.

It finally had the function of efficiently converting thermal energy, from the coal that was being burned to supply the heat, into mechanical energy, which worked the engine’s parts. This prefigured, a century beforehand, the concepts of energy and thermodynamics that in Victorian times became commonplaces of industrial science.

As was said in the text of Watt’s patent, with admirable clarity, “in engines that are to be worked wholly or partially by condensation of steam, the steam is to be condensed in vessels distinct from the steam vessels or cylinders, although occasionally communicating with them.

“These vessels I call condensers, and whilst the engines are working, these condensers ought at least to be kept as cold as the air in the neighbourhood of the engines by application of water or other cold bodies.”

The patent did not produce an immediate effect because Watt did not have enough money to exploit it. He had started off with support from John Roebuck, head of the Carron Ironworks at Falkirk, who, however, went bust in 1768. The interest in the steam engine was sold off to Matthew Boulton of the Soho Manufactory near Birmingham. His experienced workers provided Watt with the precise metalworking needed for his new engines.

Watt constantly sought improvements. Soon he and Boulton were making their own fortunes as their steam engines transformed textile mills and just about every other facet of the Industrial Revolution.