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No. 1615:
Learning to Use Coal

Today, we learn why we shouldn't bring coals to Newcastle. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

History does offer some reports of the ancients burning coal. But when Marco Polo went to China in the late thirteenth century, he was still surprised to see black stones being burned there. He would've been equally surprised if he'd gone to England. For the English were already using coal for smithing, brewing, dyeing, and smelting. The English had even begun exporting it to France.

European millwrights had been building waterwheels of wood for three centuries by then, and they were now beginning to build the new windmills as well. Iron smelting was an even worse destroyer of forests. To smelt one pound of iron took about eight cubic feet of wood, which had first been made into charcoal.

Wood became too precious to keep burning as fuel. In AD 1205 an Italian settlement created a reforestation plan in which each citizen had to plant ten trees a year. Such measures were not enough. By AD 1230, the English had to start importing Scandinavian timber.

But they also learned to replace wood fuel with surface coal, also called sea-coal. That's because the largest outcroppings of the stuff were to be found near the English coast.

The reason we don't bring coals to Newcastle is that sea-coal deposits surrounding that city were mined in open cuts thirty feet deep. Newcastle was soon girdled by a dangerous maze of water-filled trenches.

Sea-coal was filthy stuff, loaded with bitumen and sulfur. It created environmental problems from the start. As early as AD 1257, fumes from the city below drove Eleanor, Queen of England, out of Nottingham Castle. But the medieval population explosion drove people to use this foul fossil fuel anyway. An anonymous fourteenth-century balladeer vented his anger at its use:

Swart smutted smiths, smattered with smoke,
Drive me to death with din of their dints; ...
The crooked caitiffs cryen after col! col!
And blowen their bellows that all their brain bursteth.

For a century or so, medieval environmentalists fought with medieval industrialists over the use of coal. Then famine and plague ended their argument until the middle of the fifteenth century.

As Europe began repopulate after the plague, people returned to coal, using the new techniques of metal mining. With more people smelting metals, wood shortages reappeared. So people followed coal seams into the earth, mining it the way they mined metal.

They found their way down to the clean hard coals that we use today. Just over two centuries ago, we learned to make coke from those coals and use it in place of charcoal for smelting steel.

For six hundred years, coal, wood, and metal swirled about one another. As energy needs keep changing, coal, which Emerson once called "a portable climate," could well emerge to play some new role in the ongoing balance of human cold and warmth.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Gimpel, J., The Medieval Machine. New York: Penguin Books, 1976.

For a complete account of medieval mining, see: Agricola, G., De Re Metallica. (tr. by Herbert Clark Hoover and Lou Henry Hoover) New York: Dover Publications, Inc., 1950. (reprint of the 1912 edition.)

This is a greatly revised version of Episode 135.

Agricola's picture of sixteenth-century iron smelting

Agricola's picture of sixteenth-century iron smelting