James Watt was a Scot who, at nineteen, spent a year in London studying instrument-making. Then he returned to Glasgow to open up his own shop. Within a year, he was made "Mathematical Instrument Maker to the University of Glasgow." At first, he worked on many things -- even musical instruments.
Then, in 1763, a professor brought him a task that changed history. The Newcomen engine model bought for the natural philosophy course at the university, had never run for more than a few strokes. They'd sent it off to an instrument-maker in London who couldn't make it run. And they wondered, what was wrong? Could Watt identify the problem and eliminate it?
The Glasgow model of a Newcomen engine presented to Watt for rework (after Thurston)
Watt saw the problem. Fixing it was another matter. The problem was that each time steam was admitted, it entered a cylinder cooled by the condensation that'd just taken place. Most of the steam condensed on the cold cylinder wall. Very little of it remained to create a working vacuum. How to keep the walls hot after the condensation stroke?
In 1764 Watt finally had an answer: If he could separate condensation from the cylinder, the cylinder would stay hot and the condenser cold. No more wasted steam! Of course he had to use a vacuum pump to hold his external condenser at very low pressure. In any case, 1764 was a great year for Watt. He also married his cousin Margaret Miller that summer, and things were good -- at least for a while.
But now Watt had to make a working engine, and the wind shifted. He was soon going broke, so he sold two thirds of his patent to a speculator named John Roebuck. Roebuck's iron works were in trouble because its coalmines were flooding. He meant to use Watt's engine to pump them out. But the engine still had too many bugs. Then Roebuck made some bad business deals and had to sell off his holdings to get out of debt. And no one would put up a farthing for his share of Watt's patent.
Watt's first engine design
The Birmingham industrialist Matthew Boulton finally saw what others had not. He bought Roebuck's share of the patent for £1200 and bailed out both Watt and Roebuck. Watt kept struggling during the next four years. His wife tried to buoy him. "If it will not do, something else will," she wrote. "Never despair." Meanwhile, two of their children died as infants. Then Margaret died in 1773, and the last threads of Watt's life seem to come undone. Finally Watt wrote, "I know grief has its period; but I have much to suffer ... ."
His fortunes finally turned in 1776. His engine was running and he moved to Birmingham to go into production with Boulton. He also remarried. That was the year when Boulton was able to say to Samuel Johnson's biographer, James Boswell, "I sell here, Sir, what all the world desires to have -- POWER."
And there's the fulfillment of the path taken by the English dissidents. They'd embraced steam power at the turn of Watt's century; now they had economic power. Watt's external condenser had roughly doubled the efficiency of Newcomen's atmospheric engine, and that was only the beginning.
Watt would bring far more inventive genius to the steam engine before he was done. He also brought us to another door -- one through which he would choose not to pass. And that was the door that would lead us into a new fixation -- a fixation upon speed.
A more fully evolved Watt engine
The many good biographies of James Watt are generally consistent; I recommend J. P. Muirhead, The Life of James Watt, with Selections from His Correspondence. 2nd ed., revised. London: John Murray, 1859; M. Arago, Life of James Watt. 2nd ed. (Edinburgh: Adam & Charles Black, 1839) (M. means "Monsieur." Arago's initials were D.F.J); R. H. Thurston, A History of the Growth of the Steam Engine. (New York: D. Appleton, 1888); A. Carnegie, James Watt, (New York: Doubleday, Doran & Co., 1933/1905), and I. B. Hart, James Watt and the History of Steam Power. (New York: Henry Schuman, 1949).