The Most Powerful Idea in the World

by William Rosen

  Muscle, either human or animal;

  Water; or

  Wind.

  Muscle power is, needless to say, older than civilization. It’s even older than humanity, though humans are considerably more efficient than most draft animals in converting sunlight into work; an adult human is able to convert roughly 18 percent of the calories he consumes into work, while a big hayburner like a horse or ox is lucky to hit 10 percent—one of the reasons for the popularity of slavery throughout history. The remaining two were, by the seventeenth century, relatively mature technologies. More than 3,500 years ago, Egyptians were using waterwheels both for irrigation and milling, while at the other end of Asia, first-century Chinese engineers were building waterwheels linked to a peg and cord that operated an iron smelter’s bellows; the following century, another Chinese waterwheel used a similar mechanism for raising and dropping a hammer for milling rice. The first-century historian known as Strabo the Geographer described a water-driven mill for grinding grain in the palace of Mithridates of Pontus that was built in 53 BCE. A century later, the Roman architect and engineer Vitruvius (the same one who inspired Leonardo’s “Vitruvian Man”) designed, though possibly never built, a water mill that used helical gearing to turn the rotation of the wheel into the vertical motion of the grinding stone, “the first great achievement14 in the design of continuously powered machinery.”

  Europeans had been putting water to work for hundreds of years before they started harnessing the wind, possibly during the tenth century, and certainly by the twelfth. This was probably due to the fact that, even more than waterwheels, the utility, and therefore the ubiquity, of windmills was a function of geography. They were, for example, common in northern Europe,15 because of the flat topography, and their comparative advantage in a climate where rivers freeze in the winter, but rare enough in the Mediterranean that Don Quixote could still be astonished by the appearance of one.

  Windmills and waterwheels were, and are, used for everything from pumping water to sawing wood to operating bellows to smoothing (the term of art is fulling) wool. As we will see, it was a century before steam engines were used for a function that was not previously, and usually simultaneously, performed by wind or water mills. Their most important function, however, from antiquity forward, was milling grain; in the case of muscle power, the same grain used for feeding the draft animals themselves.

  Whatever their productivity in milling grain, wind and water mills suffered from two fundamental liabilities, one obvious, the other less so. The first was the fact that water mills, especially, are site-specific; work could be performed by them only alongside rivers and streams, not necessarily where the work was needed. The second, however, proved to be the more significant: The costs of wind and water power were largely fixed, which profoundly reduced the incentives to improve them, once built, any more than someone who bought a car that came with a lifetime supply of gas would seek to drive economically. One can make a water mill more powerful, but one cannot, in any measurable way, reduce its operating expenses. The importance of this can scarcely be underestimated as a spur to the inventive explosion of the eighteenth century. So long as wind, water, and muscle drove a civilization’s machines, that civilization was under little pressure to innovate. Once those machines were driven by the product of a hundred million years of another sort of pressure, innovation was inevitable. One is even tempted to say that it heated up.

  COAL IS SUCH A critical ingredient for the Industrial Revolution that a significant number of historians have ascribed Britain’s industrial preeminence almost entirely to its rich and relatively accessible deposits. Newcomen’s engine, after all, ran on coal, and was used to mine it. One would scarcely expect to read a history of the steam engine, or the Industrial Revolution, without sooner or later encountering coal.

  Encountering it in the same chapter that documents the rise of the experimental method is perhaps a little less obvious. But that proximity is neither sloppiness nor coincidence; the two are subtly, but inextricably, linked. The mechanism by which the steam engine was first developed, and then improved, was a function not only of a belief in progressive improvement, but of an acute awareness that incremental improvements could be measured by reducing cost. Demand for Newcomen’s steam engine was bounded by the price of fuel per unit of work.

  For a million years, the fuel of choice for humans was hydrocarbons, in the form of both wood and charcoal, but it did no work, in the mechanical sense. Instead, it was used exclusively to cook food and combat the cold, and, occasionally, to harden wood. Several hundred thousand years later, a group of South Asians, or possibly Middle Easterners, discovered that their charcoal fires also worked pretty well to turn metals into something easier to make into useful shapes, either by casting or bending. For both space heating and metalworking, wood, the original “renewable” fuel, was perfectly adequate; measured in British Thermal Units—as above, the heat required to raise the temperature of one pound of water 1°F—a pound of dry wood produces about 7,000 BTUs by weight, charcoal about 25 percent more. Only as wood became scarce did it occur to anyone that its highest value was as a construction material rather than as a fuel. It takes some fourteen years to grow a crop of wood, and burning it for space heating or for smelting became a progressively worse bargain.

  Europe’s first true “wood crisis”16 occurred in the late twelfth century as a bit of collateral damage from a Christian crusade to destroy the continent’s tree-rich sanctuaries of pagan worship and open up enough farmland to make possible the European population explosion of the following centuries. A lot more Europeans meant a lot more wooden carts, wooden houses, and wooden ships. It also meant a lot more wood17 for the charcoal to fuel iron smelters, since smelting one pound of iron required the charcoal produced by burning nearly eight cubic feet of wood. By 1230, England had cut down so many trees for construction and fuel that it was importing most of its timber from Scandinavia, and turned to what would then have been called an alternative energy source: coal.

  Coal consists primarily of carbon, but it includes any number of other elements, including sulfur, hydrogen, and oxygen, that have been compressed between other rocks and otherwise changed by the action of bacteria and heat over millions of years. It originates as imperfectly decayed vegetable matter, imperfect because incomplete. When most of the plants that covered the earth three hundred million years ago, during the period not at all coincidentally known as the Carboniferous, died, the air that permitted them to grow to gargantuan sizes—trees nearly two hundred feet tall, for example—collected its payback in the form of corrosion. The oxygen-rich atmosphere converted most of the dead plant matter into carbon dioxide and water. Some, however, died in mud or water, where oxygen was unable to reach them. The result was the carbon-dense sponge known as peat. Combine peat with a few million years, a few thousand pounds of pressure, several hundred degrees of heat, and the ministrations of uncounted billions of bacteria, and it develops through stages, or ranks, of “coalification.” The shorter the coalification process, the more the final product resembles its plant ancestors: softer and moister, with far more impurities by weight. Or so goes the consensus, “biogenic” view of coal’s natural history; an alternative theory does exist, arguing that coal and other fossil fuels have a completely geological origin. The theory, arrived at independently in the 1970s by Soviet geologists and the Austrian-born astrophysicist Thomas Gold,* contends that the pressures and heat present in what Gold called the “deep hot biosphere” formed the hydrocarbon fuels currently being used to run the world’s energy economy, and the presence of biological detritus in coal and other “fossil” fuels is a side effect of the bacteria that fed on them.

  Whether as a result of geologic or biogenic forces, each piece of coal is unique, the result of both different plant origins and differing histories of pressure, heat, and fermentation. What they have in common is that they all share the same relationship between time and energy: Over thousands of millennia, h
ydrogen and hydroxyl compounds are boiled and pushed out, leaving successively purer and purer carbon. The younger the coal, the greater the percentage of impurities, and the lower the ranking. In fourteenth-century Britain, lower-ranked minerals like lignite and sub-bituminous coals were known as “sea coal,” a term with an uncertain etymology but whose likeliest root is the fact that the handiest outcroppings were found along seams leading along the River Tyne to the North Sea.

  Long before concerns about particulate pollution and global warming, coal had PR problems. Almost everyone in medieval England found the smell of the sea coal obnoxious, partly because of sulfuric impurities that put right-thinking Englishmen in mind of the devil, or at least of rotten eggs; by the early fourteenth century,18 it was producing so much noxious smoke in London that King Edward I forbade burning it, with punishments ranging from fines to the smashing of coal-fired furnaces. The ban was largely ignored, as sea coal remained useful for space heating, though distasteful. Working iron, on the other hand, required a much hotter-burning fuel, and in this respect the softer coals were inferior to the much older, and harder, bituminous and anthracite. Unfortunately, along with burning hotter and cleaner—a pound of anthracite, with a carbon content of between 86 and 98 percent by weight, produces 15,000 BTUs, while a pound of lignite (which can be as little as one-quarter carbon) only about 4,000 to 8,000 BTUs—hard coal is found a lot deeper under the ground. Romans in Britain mined that sort of coal, which they called gagate, and we call jet, for jewelry, but interest in deep coal mining declined with their departure in the fifth century. It was not until the 1600s19 that English miners found their way down to the level of the water table and started needing a means to get at the coal below it.

  ANY NARRATIVE HISTORY OF the steam engine must sooner or later make a detour underground. An Industrial Revolution without mining, and particularly coal mining, is as incomplete as rock and roll without drums. Actually, that understates the case; the degree to which cultures have solved the geometric puzzle of extracting useful ores from the complicated and refractory crust of the earth is a pretty fair proxy for civilization itself.

  At more or less the same moment in history that groups of H. sapiens started digging a few inches into the dirt in order to plant seeds, they also began digging a little farther looking for flint that could be chipped into useful shapes. Even earlier, some forty thousand years ago, the caves at Lascaux were decorated with, among other things, pigment extracted from the iron ore known as hematite. Sometime thereafter, every community of humans discovered that clay plus fire equals pottery, and, by about 4000 BCE, that the earth contained semiprecious stones like turquoise and malachite, and easily worked metals like gold, and especially copper. The Roman mines along the Rio Tinto (named for the color its copper ore gave the water) in southern Spain not only provided precious metals but mechanized the process for the first time, using aqueducts to wash the debris out of the excavation and waterwheels to crush the ore left behind. And, of course, for four centuries Roman Britain was a source of silver, copper, and gold—and jet—for the imperial treasury.

  The demand for Roman engineering was a function of the change from surface to deep mining, though the adjective is a relative one. The deepest mine in the world, at 2.4 miles down, is the Tau Tona gold mine outside of Johannesburg; the world’s deepest coal mine is barely three-quarters of a mile to the bottom, which means that the most elaborately dug structures in mining history have scratched only the tiniest fraction of the mineral trove of the planet.*

  Despite six millennia of improvement in mining technology, the “scratching” is actually more dangerous today than it was in the Neolithic period, and nearly as hazardous as it was for medieval pick-and-axe miners. Once the potential for surface mining, which is the complete removal of the ground cover, was exhausted, the only recourse for coal extraction was digging, usually into a hilltop. Whether the goal was hard coal or soft, the first step in such digging was mounting a large bore auger on a framework, rotating it, usually by either men or tethered mules walking in circles, and adding segments to it as it drilled deeper. The auger was followed by miners using tools, primarily picks, to carve coal from seams (some up to 100 feet thick) in a “room-and-pillar” method at the face, and transporting the coal by cart to the adit, or borehole entrance. With increasing depth, water-driven elevators or skip buckets were used to carry coal to the surface. In medieval England, the combination of technical difficulty with the ever-present risk of cave-in, flooding, and sharp tools wielded in close quarters meant that miners were treated like a relatively privileged class; unlike tenant farmers, they dug without obligation to the lords whose lands they worked, living “in a state within a state,20 subject, only, in the last resort, to the approval of the Crown.”

  As coal mines went deeper, they also became more dangerous, and not merely because of the engineering challenge of supporting tons of overburden; one of the volatile components of raw coal is the hydrocarbon CH4, or methane, which is the main component of the flammable mixture known as “firedamp.” Though it is slightly lighter than air, it can still pool in sealed areas of mines, causing a danger of asphyxiation and, far more significant in an age in which the only illumination came from fire in one form or another, explosion.* Savery’s “Miner’s Friend” was not, as it happens, sold exclusively as a water pump, but also as a means for ventilating such mines.

  Anything that improved mining was attractive to the innovators of eighteenth-century England. Three-quarters of the patents for invention granted prior to the Savery engine were, one way or the other, mining innovations; 15 percent of the total were for drainage alone,21 as the shortage of surface coal became more and more acute and prices rose.

  Price is the mechanism by which we allocate the things we value, from iPhones to coal, and even an imperfect system sooner or later incorporates the cost of manufacture into the selling price. In 1752, a study was made22 of a 240-foot-deep coal mine in northeast England in which a horse-driven pump lifted just over 67,000 gallons every twenty-four hours at a cost of twenty-four shillings, while Newcomen’s engine pumped more than 250,000 gallons using twenty shillings’ of coal—a demonstration not only of the value of the engine, but of a newfound enthusiasm for cost accounting. Newcomen’s engine, by pumping water out of deeper mines at a lower cost, also lowered the effective price.

  The problem was that it didn’t lower it enough. The coal-fired atmospheric engines of the type designed by Newcomen and Calley burned so much coal for the amount of water they pumped that the only cost-effective place for their use was at the coal mine itself. This did a lot more for heating British homes than running British factories; as late as the 1840s,23 the smoky fireplaces of British homes still consumed two-thirds of Britain’s domestic coal output, and a shocking 40 percent of the world’s. An eighteenth-century coal porter in London might carry loads of twice his own weight up rickety stairs and even ladders up to sixty times a day. But no one was using steam engines for much else, because the cost of transporting the coal to a steam engine more than a few hundred yards from the mine itself ate up any savings the engine offered.

  For fifty years, lowering the cost of mining coal for heat had been enough to make the Newcomen engine a giant success. It was dominant in Britain, copied all over Europe, and even studied at universities—unsurprisingly, given the experimental methods that had created the engine in the first place. One of the universities interested in producing a superior version of the Newcomen engine was the University of Glasgow, the fourth oldest in the English-speaking world, and home not only to Joseph Black but to James Boswell, Adam Smith, and a dozen other leading lights of what came to be known as the Scottish Enlightenment.

  And, of course, to James Watt.

  * The modern definition of experimentation—isolation of a single variable, to test and record the effect of changing it—still lay a hundred years in the future. We will meet the creator of this sort of experimental design, John Smeaton, in chapter 6. />
  * Modern engineers generally measure this as kilojoules/kilogram, but in British Thermal Units (the amount of heat needed to raise the temperature of a pound of water 1°F) the numbers are 144 and 965 respectively. Thus, it takes 144 BTUs to turn a pound of ice at 32° into a pound of water at 32°, and 965 BTUs to convert a pound of water at 212° into steam.

  * Gold died in 2004 after four decades at Cornell University and a lifetime of swimming outside the mainstream of scientific orthodoxy. In the 1950s, along with Fred Hoyle, Gold was the originator of the so-called steady state theory of the universe, which preceded and contradicted the generally accepted big bang theory.

  * A back-of-the-envelope calculation, using 33 × 1012 cubic miles as the rough spherical volume of the planet, concludes that excavating a truly giant mine—2.4 miles down, a mile on a side—gets at no more than 7 × 10-9 of the earth’s volume. Barely a scratch.

  * An explosion is essentially a fast-burning fire with nowhere to go. Firedamp, however, can also burn slowly. Very slowly. The mine fire that started in Centralia, Pennsylvania, in May 1962 is, as of this writing, still burning.

  CHAPTER FIVE

  SCIENCE IN HIS HANDS

  concerning the unpredictable consequences of sea air on iron telescopes; the power of the cube-square law; the Incorporation of Hammermen; the nature of insight; and the long-term effects of financial bubbles