By 1700, the British Isles had a problem. Their forests were nearly gone. Coal had become the main heating fuel for the swelling population, but the easy surface coal had been mined out. Deeper seams were flooding faster than horse-driven pumps could empty them.

In 1712, a Devon ironmonger named Thomas Newcomen built a strange machine in a mining region called Dudley. It was enormous: a tower-sized boiler, a single tilting beam, a cylinder big enough to walk into. The mechanism worked by alternately filling the cylinder with steam, then condensing it with a jet of cold water. The vacuum sucked a piston down. The motion drove a pump.

The Newcomen engine was wildly inefficient. It burned mountains of coal per stroke. But mines had limitless coal, and it could lift water from depths no horse team could match. By 1730 there were over a hundred Newcomen engines pumping British mines.

Then in the 1760s, a Glasgow instrument maker named James Watt was repairing a Newcomen for a university. He noticed the cylinder was reheated and recooled every cycle, wasting most of the fuel. He added a separate condenser. Efficiency tripled. Coal use plummeted.

Watt's improved engine was efficient enough to be used away from coal mines. Soon textile mills, foundries, and breweries ran on steam. Then George Stephenson put one on wheels and invented the locomotive.

A pump for coal mines became the engine of industrial civilization. Within a century, steam-powered factories had transformed labor, urbanization, and the global economy.

Nobody planned it. Newcomen just wanted to pump out a flooded coal seam.