JAMES WATT'S role in the evolution of steam power is often misrepresented. He did not invent the steam engine, despite all that eighteenth-century propaganda about him watching a kettle boiling on the kitchen range and noticing how the steam raised the lid. Someone had noticed that a long time before him.
In fact, engines using steam were running well before Watt was born. The Scot's claim to fame is based on the radical improvements he made to Thomas Newcomen's atmospheric engine, which turned steam into the major power source of the Industrial Revolution. He truly introduced the Age of Steam.
Yet a closer look at his story suggests that Watt was by no means the great guiding light of the Industrial Revolution that so many people assume. His proprietorial attitude to steam power may well have delayed Britain's industrial progress for a decade or more, with far-reaching consequences.
Watt was born in Greenock on the River Clyde in Scotland in 1736, the son of a merchant. At 18, he went on horseback to London to train as a mathematical instrument maker. He returned to perform this job for Glasgow university for six years and still found time to supplement his income by carrying out surveys for the Forth and Clyde, Caledonian and other canals.
It was while repairing a model of a Newcomen engine for the university in 1763 that he noticed the deficiencies of the machine, and had the idea for a separate condenser.
Newcomen's engine had worked by using steam to create a vacuum beneath a piston inside a cylinder. The vacuum was formed by condensing the steam using a water spray inside the cylinder, allowing atmospheric pressure to force the piston downwards.
Watt realised that cooling the cylinder in this way on every stroke, then heating it again with the introduction of more steam, was a massive waste of energy. His solution was to divert the spent steam out of the cylinder and into a separate chamber, called a condenser, where it was cooled. This allowed the cylinder itself to remain hot and more efficient throughout the cycle.
Newcomen's cylinder had been open at the top, allowing the atmosphere to do the work - the steam he used was at little more than atmospheric pressure, and was there simply to fill the space beneath the rising piston and to create the vacuum as it was reduced back to water.
But Watt decided to make the steam do all the work. He sealed the top of the cylinder, increased steam pressure and introduced it alternately to the top and bottom of the piston. The result was a huge increase in power and efficiency.
Watt was by no means a rich man, and he knew he needed money and facilities to develop his idea. His problem seemed to be solved when he went into partnership with Dr John Roebuck, proprietor of the Carron Ironworks near Falkirk
A WATT engine of 1787, equipped with rotatory motion and the engineer's patent governor. The boiler is on the extreme left, supplying steam to the cylinder, whose piston raises and lowers the beam which turns the big wheel.
But fortuitously for Watt, the partnership failed when Roebuck's business hit hard times. It allowed him to form his famous partnership with Matthew Boulton at Birmingham's Soho Works in 1774.
Watt's engine was quickly seen to be superior to Newcomen's. It was more powerful, more reliable and used only about a third as much coal as its predecessor. With successive patents between 1781 and 1785 for improvements, such as the sun-and-planet motion, the expansion principle, parallel motion and a smokeless furnace, he further refined the system.
An air pump, a steam jacket for the cylinder and the double-acting principle also flowed from his fertile mind.
Boulton and Watt engines were soon replacing uneconomic Newcomen machines in Cornish mines. Boulton introduced a novel charging system to help sell the engines: The customer paid for the parts and labour, plus an annual percentage of the saving in the cost of coal compared with a Newcomen device.
Having perfected the pumping engine to his own satisfaction, in 1781 Watt turned his attention to developing a rotary motion, rather than the up-and-down motion of the pumping engine.
Within two years, Richard Arkwright had a Watt engine installed in his Nottingham mill, and soon Soho-built engines were powering the cotton mills of Lancashire and were in use in industry throughout the country. By 1800, when his patents finally expired, there were more than 500 of Watt's machines in Britain's mines and factories.
However, it is impossible to escape the conclusion that the dog-in-a-manger attitude of Watt and Boulton delayed the course of the Industrial Revolution for several years. And in the end, their cumbersome, low-pressure engines proved a blind alley. High-pressure, non-condensing engines were the way forward.
MATTHEW Boulton's magnificent Soho Manufactory in Birmingham and, right, the hive of activity inside the factory.
But the pair protected their interests so well that virtually all development in that direction was stymied - even William Murdoch, one of their own employees, was barred by law from developing the steam carriage he had invented.
Nothing would induce Watt to develop engines using what he termed "strong steam". He felt the idea was inherently dangerous. Thankfully, others thought differently and with the expiry of Watt's patent, men like Richard Trevithick moved in to take steam power to the next level, with more powerful, lightweight engines that could be mounted on wheels and made to pull wagons. Without high-pressure steam, the age of the locomotive would not have dawned.
Watt retired in 1800, having done much to transform the industrial landscape. He died at his home, Heathfield Hall, near Birmingham, in 1819. The watt, a unit of power, is named after him, and it was he who first coined the term 'horsepower.'
In 1817, Watt's son, James, fitted the engine to the SS Caledonia, the first ocean-going steamer to leave port.
James Watt