concerning the unpredictable consequences of banking crises; a Private Act of Parliament; the folkways of Cornish miners; the difficulties in converting reciprocating into rotational motion; and the largest flour mill in the world

DURING THE FIRST HALF of the eighteenth century, the technology of iron and steel manufacture experienced more innovation than it had during the preceding two thousand years: further evidence of the enthusiasm with which artisans, especially in Britain, greeted the security that both law and culture now granted their inventions. But while the new alchemists—Darby, Huntsman, Cort, and a hundred other, less well remembered inventors—were getting rich by turning base metal into gold, their coke-fueled smelters and puddling furnaces did far more to increase the supply of iron than the demand for it.

This was a bigger hurdle for the inventors of the eighteenth century than for their predecessors, since the incentives that prompted innovations from members of the artisan class were overwhelmingly financial; Leonardo might invent to satisfy his own curiosity, or the ambitions of a Borgia, but Abraham Darby needed customers. So until orders from those customers increased as fast as production, the growth curve of the iron business was at best a straight line with a mild upward slope. And linear growth, even when driven by innovations as dramatic as the atmospheric steam engine, was insufficient, because of population’s stubborn tendency to grow exponentially.

Exponential growth in iron production required exponential growth in iron demand. The likely source for that demand, however, wasn’t immediately obvious to the era’s ironmongers. The Royal Navy, still the largest customer for fabricated iron, was already launched (sorry) on the dramatic buildup that would see its size triple by the time of the Napoleonic Wars, but its ships were still made of wood, and driven by sails. Steam engine components were a promising enough source1 of new orders for cast and wrought iron that by 1750 the Coalbrookdale foundry alone had built the boilers and cylinders for more than one hundred and fifty Newcomen-style engines. Virtually every one of them, however, used so much fuel to pump water that the only place they were even close to economical was at the heads of the coal mines themselves, which put a severe limit on their appeal.

This was, of course, the opportunity that Matthew Boulton saw in James Watt’s separate condenser: An invention that delivered the same amount of pumping force using half the coal would liberate steam engines from the tethers that bound them to their fuel source. And that meant that they could be used not only to pump water out of Cornish tin mines, but to pump the bellows of Shropshire iron smelters, and the hammers of Sheffield forges. The Soho Manufactory would buy iron from Britain’s foundries and sell them engines in return.

Boulton’s February 1769 letter, the one that included his grandiloquent but persuasive offer to make steam engines “for all the world,” was tempting to Watt. John Roebuck, on the other hand, was still convinced that the Watt engine was worth a fortune, and that he was the man best equipped to bring it to market. He was correct on the first count, but not the second; throughout Roebuck’s life, his business sense was never equal to his vision, and his finances were, in consequence, always in disarray. In September 1769, his need for investment capital became acute enough that he offered to make Boulton a minority partner in his business. They concluded the deal on November 28; Boulton would receive one-third of the rights to the patent in return for £1,000—more than $150,000 in current dollars, about one-third of Roebuck’s investment to date; by way of comparison, Watt’s 1770 salary2 as a surveying engineer on the Monkland Canal was £200. With this money in hand, Roebuck was able to finance Watt’s continued work at Kinneil, though only fitfully. Three full months in 1770 were taken up in attempting to produce a perfectly round cylinder that would not deform under the pressure of a piston, but the ironmasters at Roebuck’s Carron foundries consistently disappointed. Three years after the deal was struck, Boulton’s one-third share in the profits from the 1769 patent had precisely the same value as Roebuck’s two-thirds: nothing. While Watt was able to support his family surveying canals, and involved himself in other of Roebuck’s ventures, the patent wasn’t generating enough revenue to buy the coal needed to boil a teapot’s worth of water. Roebuck, however, needed those profits. The eighteenth century was no less immune than the twenty-first to credit crises, and Carron’s founder was, like thousands of others, caught up in one: In 1772, Glasgow’s recently established Bank of Ayr,3 the country’s most liberal in granting credit, collapsed, bringing down virtually every other private banker in Scotland with it. In 1773, Roebuck’s business interests, an unsteady edifice at the best of times, were caught up in the panic, and he officially came before the Chancery Court as a bankrupt.

This nullified all of Roebuck’s preexisting contracts, leaving a tangle of competing claims, lawsuits, counterclaims, and disputed assets, among them the patent right to James Watt’s separate condenser. Roebuck testified4 that he had spent £3,000 on it, the equivalent of more than sixty man-years of skilled labor, and that another £10,000 (or two hundred man-years) would be needed to make it commercially viable. This seemed a poor bargain to Roebuck’s other creditors, “none of whom,” in Watt’s own words, “value the engine at a farthing,”5 but not to Boulton. He persuaded the other claimants6 to let him take over 100 percent of the patent rights in return for £630 and an agreement to drop his claims against any other part of the estate. One can imagine them elbowing each other out of the way to get Boulton’s signature before he changed his mind.

In December 1774, the last engine made with Roebuck had been dismantled, sent to Birmingham, reassembled, and put to work pumping the water that drove the Soho Manufactory’s waterwheels. Watt wrote to his father, “The business I am here about7 has turned out rather successful.”

Watt’s comment suggests both a short time horizon and a modest ambition. Boulton had neither. A strategist of both vision and enormous drive, he had acquired the rights to Watt’s patent not merely because he saw in it the solution to the Newcomen engine’s limits. Britain was thick with purchasers of atmospheric steam engines who had already realized those limits. In Cornwall, for example, copper mines were, in 1775, about to shut down because the coal needed to operate their steam pumping engines was just too expensive. Nor was it the knowledge that the separate condenser had the potential to make the engines affordable for other uses; both Roebuck and Dr. William Small, Watt’s original partners, saw the potential, and saw it early. Boulton’s genius came rather in his ability to act on this knowledge, both immediately and over the next twenty years.

The short-term objectives for the firm that was not yet called Boulton & Watt were twofold: producing a showpiece engine that would attract the business of Cornwall’s mine owners, and securing extension of the existing patent on the separate condenser that would allow the firm to profit from that business for the longest possible time.

So long as Watt was working under Roebuck’s supervision at Kinneil, Boulton, as the minority partner, found it impossible to stay informed of the project’s successes and failures; in 1770, Watt had attempted to reinforce his balky cylinder with longitudinal supports, but when it failed to keep the cylinder airtight, Roebuck never notified Boulton. With Watt working at Soho, Boulton was able to see the project clearly for the first time, and he calculated that the firm would need until 1800 or so to break even on the investment still needed to perfect the Watt engine.

Unfortunately, the original patent was due to expire in 1783; Roebuck’s eagerness to pursue patent protection in 1769 had returned to haunt Watt. Boulton’s simple solution was to start over and seek an entirely new patent. In January 1775, Watt, having checked in with his London patent agent, agreed, writing, “we might give up the present patent,8 and [there is] no doubt that a new one would be granted.” Boulton, so inspired, arranged for a bill requesting an Act of Parliament to be introduced in February of 1775, probably with the sponsorship of the Scottish MP William Adam.

It’s probably overreaching to call that Act of Parliament, formally the “Fire-Engine Act of 1775,” “the most important single event9 in the Industrial Revolution” (as at least one modern historian termed it), but it does remind the observer that an invention acquires a good bit of its value from the social system in which it is created. It is also a reminder, if another were needed, that even the creators of history’s most revolutionary innovations were subject to the same conservative temptation as the most traditional guildsman: to protect advantage once it was acquired. Economists still debate whether the 1775 patent extension promoted or inhibited innovation in steam technology; even the strongest critics concede that if it did retard innovation, it did so for at most a decade, which seems modest enough in the great sweep of history. No one can doubt the importance that Boulton and Watt placed on it. And the effort they were willing to expend in overcoming any obstacles to its passage, including the opposition of the great Whig statesman Edmund Burke, whose enmity Boulton had earned by taking a different side on the question of rights for the fractious—remember, this was 1775—American colonists.

Burke’s antagonism was unable to kill the Act, though it did delay its passage until May 10 (the same day Ethan Allen and Benedict Arnold captured Fort Ticonderoga). By then, a combination of clever persuasion and judicious arm twisting had gotten Matthew Boulton what he wanted: a twenty-five-year extension. The Act reads, in part:

AND WHEREAS, in order to manufacture10 these engines with the necessary accuracy, and so that they may be sold at moderate prices, a considerable sum of money must be previously expended in erecting mills, and other apparatus; and as several years, and repeated proofs, will be required before any considerable part of the publick can be fully convinced of the utility of the invention, and of their interest to adopt the same, the whole term granted by the said Letters Patent [i.e. the original 1769 patent] may probably elapse before the said JAMES WATT can receive an adequate advantage to his labor and invention:

AND WHEREAS, by furnishing mechanical powers at much less expense, and in more convenient forms, than has hitherto been done, his engines may be of great utility in facilitating the operations of many great works and manufactures of this kingdom; yet it will not be in the power of the said JAMES WATT to carry his invention into that complete execution which he wishes, and so as to render the same of the highest utility to the publick of which it is capable, unless the term granted by the said LETTERS PATENT be prolonged.

The merits of Boulton’s argument aside, the decision to pursue a private Act of Parliament is also a reminder that medieval guildsmen weren’t the only ones to see competition the same way that the young Saint Augustine viewed chastity and continence: something to pray for, sed noli modo: but not yet. Economists have studied the human predilection for shutting out competitors once they have achieved a position of prosperity, and they refer to the behavior that follows as “rent seeking.” Rent-seeking behavior is simply the practice of earning income from an asset without currently working at it. Landlords are rent seekers, particularly to the degree that the land in question is unimproved, and inherited. So are monopolists. And so, indeed, are owners of copyrights and patents, so much so that one of the head-spinning challenges faced by Enlightenment thinkers like Adam Smith was to reconcile their antipathy to all forms of rent seeking, particularly in the form of state-chartered monopolies, with their enthusiasm for inventors and technological innovation. The British Society of Arts,11 whose mission was “to embolden enterprise, to enlarge science, to refine art, to improve manufacture, and to extend our commerce,” granted more than six thousand prizes to successful inventors between 1754 and 1784—but still refused to consider patent-holders for prizes until 1845. Neither Watt nor Boulton was averse to prizes, but they scarcely thought them worth giving up their patents; nor were they averse to work, but they knew that maximizing the value of that work required keeping their competitors from using it.

Legal exclusion of competitors, of course, was valuable only to the degree that there was something valuable to protect, which is why, at the same time that his partner was working on MPs in Westminster, Watt worked furiously on two separate engines in Birmingham. The first was a water pump for the Bloomfield Colliery, a coal mine about fourteen miles from Birmingham, using a cylinder with a diameter of fifty inches, nearly three times the size of the Kinneil model. Watt, and the artisans at the Soho Manufactory—the Birmingham plant then employed six hundred men, with several dozen working directly with Watt—sweated over the new engine for more than a year. They were driven by Boulton’s plan to use the machine as an advertisement for Watt’s new design, principally the incorporation of a separate condenser, which meant that the engine had to be enormously powerful, highly economical, and utterly reliable—and obviously so.

Boulton got his wish. On March 8, the Bloomfield engine was exhibited to the public amid a ceremony that recalls Thomas Savery’s demonstration before the Royal Society at Gresham College seventy-seven years before: the Birmingham Gazette recorded “a Number of Scientific Gentlemen12 whose Curiosity was excited to see the first Movements of so singular and so powerful a Machine, and whose Expectations were fully gratified by the Excellence of its performance. The Workmanship of the Whole did not pass unnoticed, nor unadmired.”

But it was the second engine, a 38-incher intended for the blast furnaces at the New Willey ironworks that really deserved all the attention. The Bloomfield colliery engine was still, after all, a water pump, and Boulton knew that pumping water out of mines was only a stepping-stone—a profitable one, to be sure—to something much larger. Boulton wrote, “I rejoice at the well doing of Willey Engine13 and now hope and flatter my self that we are at the Eve of a fortune,” and he was right to rejoice. The engine not only gave the new design an extremely profitable seal of approval and showed off the versatility of the new engine, but it introduced Boulton & Watt to the remarkable figure of John “Iron-Mad” Wilkinson.

WILKINSON WAS A MEMBER of one of the dozen or so families with Nonconformist beliefs (in Wilkinson’s case, Presbyterianism) that dominated the iron trade in eighteenth-century England. His father, Isaac, an apprentice foundryman who became a master ironworker, was yet another of the fraternity of onetime artisans who pulled his family into the upper classes by dint of hard work, government contracts, and patent protection. In 1753 he acquired the Bersham Furnace, a foundry built by the family of Abraham Darby just across the Severn from Coalbrookdale, and became a favored supplier of cannon, shot, and shell casings—“engines of mortality of all descriptions”14—to the Office of Ordnance, a customer previously neglected by the Quaker Darbys. Four years later, in 1757, he applied for, and received, protection for his design for a cylinder-blowing engine, which used the weight of several columns of water to increase the pressure in a smelter’s bellows, and in 1758, a patent for a new method of casting and molding iron.

From the time Isaac’s son, John, was sixteen years old, he was a partner in the iron business and in 1757, father and son founded the New Willey Company, a collection of furnaces and smelters on the Severn, about three miles south of Coalbrookdale. Four years later, John was running the entire complex, and doing his best to earn his nickname. He was, indeed, mad for iron; Wilkinson may have appeared grim in person—the profile he had stamped on the copper coins he used as payment in many of his factories practically glowers—but apparently he had a large capacity for love. Not so much for his wife, or his many mistresses; but the man loved his iron. He loved it so much, in fact, that he built an iron pulpit for his church, produced iron writing tablets and pens for his children’s school, and, in legend at least, had an iron coffin constructed in which he intended to be interred and that he kept on view in his New Willey office. He even promised to visit his beloved blast furnaces seven years after his death—and his promise was so credible that, on July 14, 1815, thousands of foundrymen showed up expecting to see his ghost. But the real business of New Willey, as with Bersham, was the production of cannon.

There are few shapes simpler than a muzzle-loading cannon: an iron tube, closed at one end, with a small hole perpendicular to the long axis. Through that hole, a bit of flame ignited enough gunpowder to send a solid ball of—you guessed it—iron, weighing anywhere from ten ounces to forty-eight pounds, up to a mile and a half downrange. That kind of controlled explosion put a lot of stress on even the simplest of tubes, and early cannon had a disconcerting tendency to blow up, often enough because when the tube was cast, imperfections, known as “honeycombs,” were introduced that remained invisible until the gunpowder was ignited.

Wilkinson’s answer was to cast a solid cylinder of iron and bore out a perfectly circular hole, which created a tighter seal around the cannonball and eliminated the casting imperfections. But drilling a hole in a twelve-foot-long cannon called for a very long drill bit indeed—so long that gravity caused it to deflect downward while drilling.

Wilkinson’s great insight was to drill a pilot hole and suspend the boring head at both ends, thus guaranteeing a perfectly round tube, and to rotate the cannon instead of the drill bit. On January 27, 1774, Wilkinson turned his insight into a piece of legally protected property, patent number 1063: “a cylinder attached to a spindle15 driven by water with the drill stationary except in forward and back motion, as it is mounted on a carriage attached to rack-and-pinion.”

The result was phenomenal accuracy, a maximum error estimated at only one-thousandth of an inch. The accuracy was purchased at what seems, from the perspective of the twenty-first century, to be a huge amount of time: In 1800, boring a 64-inch cylinder16 required twenty-seven working days, and even cannon-sized cylinders could take a week. But New Willey’s customers, the Royal Office of Ordnance, were willing to wait, since the alternatives were even worse; without access to Wilkinson’s technique, the boring of a forty-inch cylinder for the Philadelphia Water Works took more than four months.

Wilkinson’s patent was intended to serve the arts of war more than those of peace, but, like radar, penicillin, and the interstate highway system, it took an unexpected turn. While the finer parts of Watt’s engines—the valves, governors, and especially the condenser—could be made by Boulton’s craftsmen at Soho, an economical engine needed a large cylinder, made of iron, and that demanded the expertise of others. Darby’s Coalbrookdale works, and the Carron Ironworks owned by Roebuck, had been the source for the earlier engines and other experimental versions, but Watt was regularly disappointed with the quality of their work, which he called, with his characteristic perfectionism, “unsound, and totally useless.”17 Even with the earlier innovations in smelting and casting, no one in Britain seemed able to cut the bore of a cylinder in the precise shape of the piston that needed to move within it—ideally with no friction and no leakage of air. Wilkinson’s nearly perfect boring system solved this problem.

Boulton and Watt may have encountered Wilkinson as early as 1768, when all three were, briefly and simultaneously, in Birmingham. Certainly they were corresponding not long after the new boring machine was patented; one of the earliest letters to Watt from Wilkinson—who had been hired, in April 1775, to produce the cylinders for both of the demonstration engines—reveals that the ironmaster had as much visionary zeal as Boulton himself: “I wish to do all in the best manner18 and to start fair. Let us only succeed well in these first engines, particularly in mine, and I will venture to promise you more orders than will be executed in our time…. Our time in this world (at best) is but short and we must be busy if you intend that all the engines in this Kingdom shall be put right in our day.” For twenty years, beginning in April 1775, when Wilkinson was enlisted to make his first steam engine cylinder for Boulton & Watt, he would remain virtually their sole supplier.

In many ways, Wilkinson had as much invested in the success of the first Boulton & Watt engines as the eponymous firm’s owners. He had seen the revolutionary impact of the New Willey engine not only on his own business—it would eventually run not only his bellows but also the forge’s stamping hammers and presses—but on all of manufacturing. If the new design caught on,19 it would create a gigantic new market for symmetrically bored cylinders—a product on which he had, as a result of his 1774 patent, a de facto monopoly.

Boulton was delighted with the ironmonger’s enthusiastic embrace of the engine, and shared his belief in the steam-powered factory. However, because he had successfully extended the Watt patent until the year 1800, he had a slightly different timetable, and his plan “to make [engines] for all the world” ran through Cornwall.

CORNWALL, THE SOUTHWESTERN TIP of the British Isles, has been dotted by tin and copper mines since at least Neolithic times. The two components of the alloy that gave the Bronze Age its name were being exported from Cornwall not later than 1000 BCE. When Julius Caesar invaded Britain in 55 BCE, his objectives included Cornish tin and copper.

The men who worked in Cornwall’s mines might have thought coal mining in Yorkshire something of a vacation: The sedimentary sheets of coal could be mined with horizontal tunnels off a single mineshaft, while the copper and tin of Cornwall, originally formed from fissures in granite, could only be mined out of individual shafts. By the middle of the eighteenth century, those shafts were the deepest in Britain, as much as eight hundred feet down. As a consequence, the typical Cornish miner traveled to and from his place of work either by whim—placing his foot in a loop of rope lowered by a mule—or by ladder, which was not only dangerous, but exhausting. A contemporary traveler described deep mining in Cornwall thus:

With hardly room to move their bodies,20 in sulphureous air, wet to the skin, and buried in the solid rock, these poor devils live and work for a pittance barely sufficient to keep them alive, pecking out the hard ore by the glimmering of a small candle, whose scattered rays will hardly penetrate the thick darkness of the place.

The work was brutal, the business eccentric. In Cornwall, landowners rarely worked the land themselves, instead leasing a “sett” for a period of twenty-one years. The lessors were generally consortia known as “adventurers” (“venture capitalist” is cognate) who put up all costs, and paid the property owner a royalty of between 1⁄15 and 1⁄32 of the value of the ore they were able to extract. Adventurers, in turn, appointed “captains”21 who were responsible for mining operations, including the hiring and management of frequently unruly miners.

Because of this system, Cornish mines were legendary for accounting practices so arcane that, in the words of a correspondent of the Cornish Telegraph, “shareholders might grumble22 over the price of a pennyworth of nails, and pass over without comment the price charged for a steam-engine.” The wide range of expertise and interest among those shareholders meant that in what was one of the world’s most class-stratified societies, miners, ironmongers, and nobles sat down for dinner four times a year at quarterly “count house dinners.”

Inevitably, drainage topped the agenda of these meetings. Because of their depth, draining Cornish mines was absolutely essential, and pumps were almost always needed, in some cases supplemented by drainage tunnels, or adits, as elaborate as the mines themselves. One of them, the Great County Adit,23 covered more than twenty square miles of Cornish mine country, and in the second half of the eighteenth century, more than half of the most advanced steam engines in the entire world were situated over the Great Adit. As Matthew Boulton realized, the demand for steam pumps, and the distance from coal mines, made Cornwall the perfect laboratory for any invention seeking to reduce the cost of mining.

Boulton’s insight would produce a genuinely innovative (not to say genuinely weird) business model. Boulton & Watt took shares in Cornish mines in return for providing engines to drain them, negotiating royalties of one-third of the difference in cost between a Newcomen-type atmospheric engine and a Watt machine doing the same work. This in turn demanded a more precise way of calculating the “same work.” The most common calculation of performance was in terms of the so-called “duty,” a measurement of the pounds of water raised one foot by a bushel of coal (confusingly, 84 lb. of coal in Newcastle, 88 lb. in London24). A high-performing Newcomen-style engine typically generated a duty of between five and nine thousand pounds; that is, a bushel of coal could lift that many pounds of water. A 1778 Watt engine, with separate condenser, achieved a duty of 18,900 pounds.

This was fine for comparing two kinds of steam engines, but less persuasive for customers who were still using wind or animal power to pump water. Watt himself came up with an alternative, measuring the pressure produced by a traditional atmospheric engine, which averaged about seven pounds per square inch, and comparing it with a Boulton & Watt engine using the separate condenser, which generated ten and a half. He then, in his careful way, recorded the effective load lifted by the two engines, using beams of the same length and weight, for the same time period. Finally, he converted it into something he called “horsepower.”

The term by then already had a long and fairly inexact history. For millennia, animals (and, all too frequently, other humans) had done most of humanity’s work and were the only power sources with variable costs. The outlay for waterpower, which was, by the eighteenth century, even more widely used and easier to measure, was entirely fixed: the construction of a waterwheel. As a result, horses were a favorite way of comparing one sort of pay-as-you-go energy with another. In the first decade of the eighteenth century, Savery himself had promised that his “impellent force” engine could “raise as much water as two Horses25 working together,” and others frequently used horse equivalents as an engineering shorthand. Getting precise about it, however, was a bit more difficult, even when everyone agreed about the need for a standard number. J. T. Desaguliers, the experimental philosopher and lecturer, thought one horse could lift 27,500 pounds a distance of one foot during one minute (or 2,750 pounds five feet in thirty seconds … you get the idea); Watt came up with 33,000 or 550 foot-pounds a second (approximately the same as 1,000 pounds at 3 mph for twelve hours a day), which is essentially the same number in use today. Rough though the measure was, horsepower was a relatively effective way to calculate the work done by pumping engines, since the weight and height of the water lifted are the only measurements required.

Watt’s horsepower offered a reasonably fair way to balance one engine against another. Boulton’s royalty system, however, tilted the balance heavily toward the engine seller, since it obliged buyers to pay one-third the difference for engines based on an ideal annual performance, while the actual engines could be out of commission for months at a time. Even when operating, they frequently weren’t replacing water or horse wheels, but supplementing them, yet intermittent use still demanded constant payment. It was a powerful disincentive against buying a bigger engine appropriate for the future needs of a business, since buyers had to pay a royalty based on an increase in use right away.

Boulton & Watt could afford to ignore any problems the system engendered so long as they were the sole suppliers of the world’s most efficient steam engines. In 1795, though, the Birmingham manufacturers discovered that John Wilkinson had been not only providing Boulton & Watt with steam engine parts, but using the same design to sell them on his own, without seeking permission or—far more important—paying a royalty for the privilege. The violent correspondence and litigation that followed is an object lesson in the principle that while ideas may want to be free, their creators very much prefer to keep them leashed.

As a result of the hostility26 between Wilkinson and his onetime Birmingham customers, they started casting the components of Boulton & Watt engines themselves, building their own ironworks at the Soho Foundry, about a mile from the original Manufactory. But whether the pieces were cast at New Willey or Soho, buyers of Boulton & Watt engines were not getting, except for the cylinder and condenser, a finished engine. In essence, the company sold a kit—no charge for the directions—with “all the cast iron,27 hammered iron, brass, & copper work … including the screw bolts of the cistern, fire door, grate barrs [and] the flywheel with its shaft.” They didn’t include the boiler, the framing for the engine house, or any of the masonry to hold the contraption, which buyers had to supply themselves, though Boulton & Watt would supply plans and estimates. Even the wooden beam itself that operated all the pumping engines was the responsibility of the buyer, though they did provide engineers to see to the final installation.

It gets better. The royalty charged by Boulton & Watt was based on the difference between the cost of the new engine and the cost of a Newcomen-style pump: the greater the savings, the higher the patent royalties. But even though running the engines was at least as demanding as building them, Boulton & Watt did not supply operators, who might have simultaneously seen to the (usually) smooth operation of the engines and their usefulness to the buyer.

The commercial relationship was further complicated by the usual problems of any industry in its infancy. To cite one critical problem, all the heavy goods needed to be transported from foundry to site at a time when the canal system was barely started—at least one Boulton & Watt engine was too large28 to travel by canal through the Harecastle tunnel—and Rocket was still fifty years in the future, to say nothing of a national rail network. In even shorter supply than transportation were skilled workmen—and they were needed not only to build the “kits” provided by Boulton & Watt (each one custom made, and no two parts assembled anywhere before they arrived on site) but to do so with extreme precision, with the shaft set at an exact right angle to the main beam and perfectly level beneath it and the pistons needing to touch either the top or bottom of the cylinder. It was in response to these demands29 that Boulton & Watt became what we would today call professional publishers, producing Directions for Erecting and Working the Newly-Invented Steam Engines in 1779.

Boulton’s plan depended on achieving at least a dozen difficult objectives, each one independent of the other, and each necessary: building a factory that could both cast and machine iron; persuading a group of adventurers to partner with him on a hypothetical cost advantage in fuel (whose future cost couldn’t even be predicted with any certainty); training a new workforce to build and operate his engines. Against all odds, it worked. Over the course of five years, Boulton & Watt’s steam engines became the pump of choice in the majority of Cornish mines.

Beginning with the installation of an engine at the Ting Tang Mine in November 1776, and the Chacewater Wheal Busy mine a month later, Watt and Boulton succeeded in impressing Cornwall’s mine operators, and even the engineers who had been building and servicing Newcomen-style machines for decades. The Chacewater engine, particularly, had been heavily promoted by Boulton as yet another demonstration of the greater efficiency of the new design—he invited hundreds of engineers and mine owners from all over Cornwall to witness the trials, and Watt himself supervised the engine’s erection. “All the world are agape,”30 wrote Watt, “to see what it can do,” and it gave “universal satisfaction to all beholders, believers or not…. Our success here has equaled our most sanguine expectations [and while] our affairs in other parts of England go on very well, no part can or will pay us so well as Cornwall.”

Boulton’s strategic plan was on schedule. He had discerned an opportunity; had exploited it;* and was soon enough unsatisfied by it. By the end of 1782, he had identified the next conquest for the steam engine, an arena whose potential dwarfed that of the mining industry: wheels.

IT IS NO ACCIDENT that “wheels of industry” is such a cliché description of a manufacturing economy, since the application of force in the form of rotational motion is by far the most important component of useful work. In late eighteenth-century Britain, the wheels that mattered most were the ones turning the mills that ground the nation’s grain, and the ones that spun the nation’s cloth. Most of them used water; some used wind. None used steam. In December 1782, Boulton wrote to his partner announcing his plan to change that: “I think that these mills represent31 a field that is endless, and that will be more permanent than these transient mines.”

He was scarcely the first to imagine the potential of a factory powered by steam. England’s manufacturers had been pestering steam engine makers on the subject for years, hoping to be freed from the shackles that bound them to the flow of rivers or wind. Unfortunately, the machines on offer were piston drivers, and using a piston to run a mill was as sensible as driving a cart by hitting it in the backside with a sledgehammer.

One idea for using a steam-driven piston to produce rotation was nearly a century old: converting linear motion into rotation by taking the new machine and using it to run a familiar one, a waterwheel. Sixty years earlier, Thomas Savery had proposed using the water pumped from mines by the steam engine to operate a 36-foot-diameter waterwheel, housed in a mill house along with the pumping engine. In the 1770s, Boulton & Watt borrowed Savery’s idea and recommended using steam engines to pump water not just out of deep mines, but into a reservoir sited well above the engine. Gravity could then pull the water past a waterwheel and so deliver rotational work, and some early steam-powered factories used just such a system, despite its inherent inefficiencies.

And so the challenge of converting the reciprocating motion of the early atmospheric engines into rotary power occupied a fair chunk of the eighteenth century. The fundamental problem of direct conversion was not ignorance; the crank and cam were well known to Newcomen and his successors. In fact, they were known to his predecessors. The teardrop-shaped cam was in use as far back as first-century Greece, and in 1783, John Wilkinson linked a steam engine to his forging hammer by means of a cam and succeeded in raising, and then dropping, the eight-hundred-pound tool. Work that can be transmitted by a cam, however, is the opposite of regular. The transfer of motion from one plane to another—converting the straight-line motion that was intrinsic to any piston-operated engine into the regular power supplied by a rotating wheel—turned out to be as big a challenge as building the steam engine itself. And as important. In the words of the twentieth-century critic Lewis Mumford, “The technical advance which characterizes32 specifically the modern age is that from reciprocating to rotary motions.”

To understand this statement requires (forgive the pun) circling back to the branch of mechanics that describes the transformation of motion from one direction to another, otherwise known as kinematics. In fact, understanding the specific transformation of straight-line into rotary motion requires detours into biomechanics, and even developmental psychology.

IN 1897, THE AUSTRIAN physicist and polymath Ernst Mach (one of the inspirational lights behind the same Gestalt theories so beloved of A. P. Usher) took a vacation from experimenting with the behavior of sound waves to examine the phenomenon of rotary motion. Mach was intrigued by the fact that Neolithic hand querns—really nothing more than two stones between which grain and other substances were ground—used reciprocating, not rotary, motion, with a horizontal handle, for millennia before evolving into rotary querns and finally rotary grindstones, which are really just querns with the upper stone turned ninety degrees. Mach, despite his knowledge of the relatively simple mathematical equations that describe rotary movement, was nonetheless confounded by his observation that infants find rotary motion nearly incomprehensible. In the words of the great medievalist Lynn White, “continuous rotary motion33 is typical of inorganic matter, whereas reciprocating motion is the sole form of movement found in living things … in Europe, at least, crank motion—a kinetic invention more difficult than we can easily conceive—was invented before the crank.”

Crank motion was tricky enough; but the first true crank-operated machine, the rotary grindstone, has to be, like the steam engine, one of history’s most embarrassingly long-gestating inventions. By the beginning of the third century, cranks were being used in China, typically for winding silk filaments. Arabs were using them34 as surgical drills for trepanning skulls perhaps six centuries later. But it wasn’t until the 1420s that cranks and crankshafts were starting to appear in Europe, in the form of the carpenter’s bit and brace; shortly thereafter, the windlass was being used to wind crossbows, and in 1430, an unknown German machinist applied double compound cranks and connecting rods—effectively an extension, or replacement, of the human arm.

The significance of the first combination of the crank with a connecting rod, of course, is that it turned rotary into reciprocal motion, and was therefore the basis of early wind and water power. The earliest visual evidence of a crankshaft35 connected to a wheel is a drawing by the fifteenth-century painter Pisanello, on display at the Louvre, that shows a water-driven piston pump in front of a crenellated tower, driving two simple cranks and two connecting rods.

Pisanello’s pump, however, was never built (though unlike so many of Leonardo’s inventions, this one would probably have worked). It wasn’t until December 1593 that a Dutch farmer named Cornelis Corneliszoon not only built a wind-powered sawmill, but, because the United Provinces had an even better developed property law than Britain, secured a patent on it lasting fourteen years.* Even better, four years later he extended the patent to embrace the use of a crankshaft that turned the rotational motion of the windmill into the reciprocating motion needed to saw wood; though because it worked in reverse, the linkage used by Corneliszoon’s sawmill (which he named Het Juffertje, or “The Little Miss”), the first of more than one thousand industrial windmills in the Zaan, is not technically a crank, but a pitman.

Reversing the process—getting a piston to drive a wheel rather than the other way around—is a trivial enough task. Attach the crank (or crankshaft: a rod connected to a wheel by a right-angled arm that pivots with the rotation of the wheel) or cam directly to the piston. But getting that wheel to rotate at a constant speed was a different matter, and any useful mechanical solution required something that smoothed out the variability in the push-pull motion of a piston—something that eliminated the “dead spot” when the piston reversed direction.

Rotating disks had been used to smooth out those dead spots—to store kinetic energy—since Neolithic times. Several millennia later, the equations of Kepler and Newton explained why: Angular momentum tends to be conserved. This is the same phenomenon that makes an ice skater spin faster when her arms are drawn in to her body, since her angular momentum is the product of her moment of inertia and angular velocity; bringing her arms closer to her axis of rotation reduces her moment, which means her velocity must increase.

A disk rotating around an axle—better known as a flywheel—does the same trick in reverse, keeping speed constant when power input is intermittent, as it always is with a piston or other reciprocating motion. Potter’s wheels, an early example, take the pumping motion of a hand or foot and convert it into relatively smooth rotation. The first flywheel used as part of a larger machine appears in Theophilus Presbyter’s Di divers artibus; by the fourteenth century, the Parisian philosopher John Buridan was observing that rotary grindstones store power, because they keep turning even when no one is turning them.

It is baffling, except perhaps in light of some infantile resistance to mixing rotary with reciprocal motion, that combining the crank with the flywheel took centuries rather than months. Not until 1740 did an inventor named John Wise suggest using a flywheel—he called it a “double tumbling wheel” in his patent*—to produce rotary motion from a Newcomen-type engine, and that went nowhere until 1778, when the engineer and inventor Matthew Wasbrough, originally from Bristol but working in Birmingham, took the first step toward a useful rotary engine, patenting (in March 1779, number 1213—things were accelerating) a complicated assortment of pulleys, wheel segments, and flywheels (“to render the motion more regular and uniform”36).

Two years later, Wasbrough incorporated a crank and flywheel into an iron rolling mill, but the circumstances were tainted. Watt, and his assistants at the Soho Manufactory, had been preparing a new design that would produce rotary motion from their existing—and highly successful—piston engine. They had been working on their own crankshaft model for more than a year when a workman at Soho leaked the plans to Wasbrough and his partners, John Steed and James Pickard. In August 1780, the three secured a patent (number 1263) for a beam-operated engine using the crank plus connecting rod (though how connected, the patent does not say).

Watt had not believed37 the crank plus rod novel enough to be patentable, because of its long history. This belief didn’t do much to calm him. In most aspects of his life, James Watt was a gentle sort, but he was extraordinarily sensitive when it came to his inventions, and he was sputteringly furious at what he saw as Wasbrough’s treachery, writing to Boulton, “I know the contrivance is my own,38 and has been stolen from me by the most infamous means…. Had I esteemed [Wasbrough] a man of Ingenuity and the real inventor of the thing in question, I should not have made any objection, but when I know the contrivance is my own and has been stole [sic] from me by the most infamous means and to add to the provocation a patent surreptitiously obtained for it, I think it would be descending below the Character of a Man to be any ways aiding or assisting to him or to his pretended inventions.”

Watt’s pride in his inventions may have been the defining characteristic of his personality. It certainly explains the amount of time he would spend in subsequent years defending his own patent claims, and frequently the claims of others, in court. The immediate reaction, however, was to take his revenge not in a courtroom, but in his workshop, and not working with a lawyer, but with another engineer, the remarkable William Murdock.

MURDOCK—ORIGINALLY MURDOCH; the Scottish spelling was anglicized—was only twenty-two years old in 1777 when he left Ayrshire in Scotland and walked three hundred miles to Birmingham, hoping for employment at Boulton & Watt. In legend, at least, Boulton asked about the young Scot’s strange-looking hat, and when he answered that the hat was made of “timmer [timber] … turned on my little lathey [lathe],”39 he evidently decided that the young Scot’s mechanical skills were sufficient to overcome his unfortunate accent. Two years later, his employers trusted him enough that they assigned him to build, unsupervised, what was only their fourth engine. Before the year was out, he was the firm’s supervisor in Cornwall.

Murdock’s relationship with Watt was complicated. The nearly twenty-year difference in their ages, their mutual affection and loyalty, their status as employee and employer, their shared Scottish heritage, and their technical brilliance in the same disciplines made for one of the more fraught Oedipal conflicts of the era. Given all the potential arenas for conflict, it is actually somewhat surprising that the relationship survived as long as it did, with the two apparently agreeing to annoy one another mercilessly in lieu of more bloody combat. Watt, in particular, regularly complained about Murdock’s tendency to second-guess (and, even more annoyingly, to improve) the master’s ideas. Anyone who has ever supervised a talented subordinate with a tendency to set his own priorities will find Watt’s letters familiar: “I wish William could be brought to do40 as we do, to mind the business in hand, and let such as Symington [William Symington, the builder of the Charlotte Dundas, one of the world’s first steam-engine boats] and Sadler [James Sadler, balloonist and inventor of a table steam engine] throw away their time and money, hunting shadows.”

Even so, Watt was nothing if not fair-minded. He may have resented the time Murdock spent inventing rather than on the company’s real business, which was installing, and collecting royalties based on the continued performance of, the Watt engines.* He was, however, just as often delighted by the inventions he made on behalf of Boulton & Watt, including a compressed air pump and a cement that would bond two pieces of iron, calling Murdock “the most active man and best engine erector I ever saw.”41 His value was never, however, to be higher than when Watt enlisted his talents on what came to be known as the sun-and-planet gear.

If the crank and its cousins are methods for turning reciprocation into rotation, then gears, broadly speaking, are methods for turning one form of rotation into another. The primary reason anyone would want to perform such a trick is the phenomenon known as the mechanical advantage, which is the formal term for the fact that when the teeth of a larger gear engage with those of a smaller, it must rotate faster for each shared revolution; since torque is defined as circumferential force multiplied by the radius, the bigger the radius, the greater the torque.

The theory and practice of gears were well known to the Greeks of the first century BCE, who were not only familiar with several basic forms of gearing (including the familiar version, in which the teeth project radially from the gear’s center, and the worm, in which another Greek invention, the screw, was set at right angles to a traditional gear) but were also capable of incorporating them into geared engines—though the nature of those engines is revealing. The best-known surviving example, the so-called Antikythera mechanism (so called because Greek sponge fishermen discovered it off the eponymous island in 1900), contains at least eighty separate bronze gears in a wooden case not much larger than the laptop computer on which this is being written.

Antikythera’s elaborately linked gears, probably used to calculate the positions of planets and stars on a particular date, posed an unanswered question to scholars for decades: Why was all this extraordinary precision and technological expertise—no comparable mechanism would appear until the clocks of the mid-eighteenth century—not used to produce anything that was recognizably useful?

The answer is related to the similar question that might be asked about Hero of Alexandria: Antikythera’s creators were the ancestors of toymakers (or, at best, clockmakers), not engineers.

Technical skill is artifact-neutral, and is just as likely to be applied to toys as tools. The builders of the Antikythera gears, like Hero, or even the great clockmakers of the Middle Ages, were just as mechanically adept as Watt or Newcomen, but they responded to a different set of incentives. Those incentives were the satisfaction of an elite segment of society with the means to commission astonishingly intricate clocks and calculators or pyramids and cathedrals. By their very nature, devices like Antikythera were built to satisfy a very different set of demands than those of a mill owner shopping for a steam engine.

Eighteen centuries later, inventors were responding to a new set of incentives—which might be the best way of explaining the Industrial Revolution. The laws of supply and demand created the market for steam-powered mills. The laws of mechanics limited the number of ways in which the back-and-forth movement of a piston could be translated into the smooth rotation of a wheel. And Britain’s property laws excluded the best one: the crankshaft. Prohibited from copying Wasbrough’s crank, Watt and Murdock nonetheless had to compete with it.

And not just compete—preempt. Whether or not Pickard and Wasbrough were guilty of theft, they had certainly convinced Watt that he was a victim of it, and he was determined not to be one again. So determined, in fact, that the patent application he and Murdock submitted in 1781 included five separate inventions, including a “swashplate” that used the engine to raise a beam through an arc that looks like nothing so much as an amusement park ride, like the pirate ship that swings high enough for its passengers to go from nearly vertical to horizontal to vertical again; a counterweighted crank wheel, with the wheel divided along a diameter with one half heavily unbalanced; and an “eccentric” wheel inside an external yoke. Most important was Murdock’s sun-and-planet gear, which linked a connecting rod to one gear that made an orbit around another, larger gear like a planet circling the sun. The last one not only smoothed out the power curve, but “gave the additional advantage42 that the output shaft rotated at twice engine speed.”*

The application, for patent number 1306, read in part, “for certain new methods43 of applying the vibrating or reciprocating action of steam or fire engines, to produce a continued rotative or circular motion round an axis or centre, and thereby to give motion to the wheels or mills or other machines.” It was submitted on October 25, 1781, but the law allowed four months to create the final specifications. Watt needed every day. Predictably, his perfectionism was once again his greatest asset and biggest liability; he regularly complained about both his health, and the quality of his assistants’ work; to Boulton he wrote, “I wish you could supply me with a draughtsman44 of abilities [as] I tremble at the thought of making a complete set of drawings…. I must drag on a miserable existence the best way I can” even though afflicted with “backache, headache, and lowness of spirits….”

But he also produced his most important patent specification since the separate condensing grant of 1769, “the neatest drawing I had ever made.”45

Fig. 5: The caption for this technical drawing reads “Mr. Watt’s Patent Rotative Steam Engine as constructed by Messrs. Boulton & Watt, Soho, from 1787 to 1800. 10 Horse power.” By 1787, the engine had evolved considerably from the earlier versions, using the sun-and-planet gear to drive the large wheel; the Watt linkage to connect the beam with the cylinder, on the left; and even Watt’s feedback-driven flyball governor—the two balls hanging above and to the left of the large wheel—to control the wheel’s speed. Science Museum / Science & Society Picture Library

THE SUN-AND-PLANET (or, for that matter, the crank plus connecting rod, which was, after all, Watt’s first choice for producing rotary motion, and would be everybody’s after the Wasbrough patent expired in 1794) was a huge step toward the introduction of steam power into mills and factories, rather than pumps. But it was only a step. The lesson of the Wasbrough imbroglio was not merely that Boulton & Watt needed to improve security at the Soho Manufactory, but also that they had to confront the uncomfortable fact that a patent was no protection against new inventions. And by 1781, invention was accelerating at a scary pace, a consequence of the time bomb that had been set by Edward Coke and John Locke in the century preceding. Consider that from 1700 to 1740, fewer than five patents were issued in Britain annually; from 1740 to 1780, the annual number had quadrupled, to nearly nineteen, and from 1780 to 1800, it was up to fifty-two.

One consequence was that46 successful technological entrepreneurs needed to spend as much time anticipating new inventions as improving their own. As Watt put it (in responding to one of many complaints about his patent specification), had he been satisfied to merely introduce his initial inventions, he would have stopped with the separate condenser; instead his mind ran “upon making Engines cheap, as well as good47 (emphasis in original). And the engine, though capable of producing relatively smooth rotary power, was still using too much coal.

It was not until the following year that he had a solution: a double-acting cylinder, in which a valve mechanism connected each end of the cylinder with both the condenser and the boiler. When the top was connected with the boiler, the bottom was connected with the condenser, and vice versa. The result was that the upward and downward strokes were identical. When the piston was up, the steam in the portion of the cylinder beneath it was condensed, causing a vacuum. And when it was down, the upper portion of the cylinder was likewise condensed. The piston was therefore both pushed and pulled, both up and down. Watt measured the pressure drop in his own cylinders, and used Boyle’s Law—the one that demonstrated the relationship between gas pressure and volume—to calculate that he could cut fuel consumption in the engine by three-quarters, while losing only one-half of the power.

In March of 1782 Watt patented the double-acting engine. The increase in power output per measure of coal was dramatic; the incorporation of a flywheel made the power even smoother. The smooth rotation of a steam-operated flywheel is one of the reasons for the rather eerie quiet of even large steam engines, at least as compared to their internal combustion counterparts; conversations in normal tone of voice can easily be heard in front of the 1,200-hp Brooklands Mill engine, built in 1893, which uses a flywheel thirty feet in diameter; a 1795 description of the first flywheel-operated steam engines remarked that they are “scarce heard in the building where they are erected.”48 But the double-acting engine also introduced a new problem: The piston needed to move the connecting rod precisely up and down.

Like so many things about steam engines, this sounds trivial but isn’t, since it illustrates what is one of the most distinctive characteristics of the steam revolution: Inventions don’t just solve problems; they create new ones, which demand—and inspire—other inventions. The double-acting engine represented a large leap in power output for every bushel of coal, but its piston now needed not just to pull a beam down but to push it up. To do so most efficiently, that piston needed to travel along a straight vertical line, or at least as straight a line as possible. However, the beam to which it was connected didn’t travel straight up and down, but along an arc, which meant its angle was constantly changing, pushing the piston off line. Earlier engines, with their single power stroke, could use a chain to pull the beam down, but obviously chains could not transmit force in two directions and wouldn’t stay straight in either direction.

Which is why Watt took out another patent, in 1784, “for certain new improvements upon fire and steam engines and upon Machines worked or moved by the same.”* The new patent included the Watt linkage, a pair of horizontal rods mounted parallel to one another, connected by a pivot to a third, perpendicular rod, which kept the piston in a straight line and so reduced the friction that caused wear on the inside of the cylinder, and, more important, wasted energy in doing so. Watt himself was uncharacteristically enthusiastic about it; in a letter to Matthew Boulton of June 1784, he announced “one of the most ingenious,49 simple pieces of mechanism I have invented.” In 1808, he wrote, “I am more proud50 of the parallel motion than of any other mechanical invention I have ever made.”

His pride was understandable. The double-acting engine, transformed by the use of flywheels, parallel linkages, and the sun-and-planet gear, liberated steam power from Britain’s mines, and Britain’s mills from the banks of her rivers. Steam engines could now be built anywhere that either reciprocating or rotary motion was needed. This was decisively proved at a site on the south side of the Thames, in London itself.

Matthew Boulton, who understood not only the potential for grain mills run by steam engines but also the need for promoting that vision to a less enlightened public, first broached the idea of a steam-powered flour mill in London sometime in 1783. While Britain’s representatives were in Paris signing a peace treaty with their former American subjects, Boulton was having somewhat less luck hammering out agreements with both the investors needed to finance his showpiece factory and the local millers whose approval was a prerequisite to a peaceful operation. Eventually failing on both counts (in a letter of 1784, he demolished each of their arguments, including the concern that the proposed mill would produce too much coal smoke, figuratively throwing up his hands with the observation that “the millers are determined to be masters of us51 and the public”), he decided to proceed anyway.

The plans for the new mill were drawn up, at Boulton’s direction, by one of Britain’s most influential architects, Samuel Wyatt, to be built on a site near the south end of the original Blackfriars Bridge. Fans of odd coincidences might take some pleasure in the fact that the north end of the bridge abutted the same Temple Bar where Edward Coke had drafted the original Statute of Monopolies, the law under which the separate condenser, sun-and-planet gear, and parallel linkage were protected. Or the slightly less coincidental fact that the engines at the mill were erected by a Boulton & Watt employee named John Rennie—the same man who would, twenty years later, build engine 42B at the Crofton pumping station on the Kennet and Avon Canal.

The Albion Mills, as it would be called, was built on a scale hitherto unimagined. The largest flour mill in London in 1783 used four pairs of grinding stones; Albion was to have thirty, driven by three steam engines, each with a 34-inch cylinder. Within months after its completion, in 1786, those engines were driving mills that produced six thousand bushels of flour every week—which both fed a lot of Londoners and angered a lot of millers.

The Albion Mills was London’s first factory, and its first great symbol of industrialization; its construction inaugurated not only the great age of steam-driven factories,* but also the doomed though poignant resistance to them. That resistance took the shape of direct action—no one knows how the fire that destroyed the Albion Mills in 1791 began, but arson by millers threatened by its success seems likely—and even poetry. It was, after all, the blackened ruins of Albion Mills that inspired Lambeth resident William Blake to write, in “Jerusalem,”

And did the Countenance Divine

Shine forth upon our clouded hills? 

And was Jerusalem builded here 

Among these dark Satanic Mills?

Blake’s vision remains powerful and chilling, but he was still whistling past a graveyard; it was the factory, in the end, that was to triumph. Albion Mills stood for only five years, but its proof of the ability of the steam engine to produce rotary power anywhere it was needed was decisive. Behind the Albion Mills engine were hundreds of large and small innovations that had solved a dozen ancient problems in physics, metallurgy, and kinematics. Before it was a new one: how to achieve clocklike (or Antikythera-like) precision in an industrial machine.

* Not without incurring a lot of resentment among the Cornish miners, who depended on the higher efficiency of the Boulton & Watt engines but hated paying for it—a time bomb that would explode in the 1790s, as we shall see in chapter 9.

* Better developed, but less successful. See chapter 11.

* Wise’s patent number was 540—forty-two years after Thomas Savery received number 356 for his “fire engine,” which adds up to fewer than five patents a year.

* Watt was not exactly immune to the temptation. During the same period, he patented a dozen other unrelated inventions, including a steam press for linen and muslin cloth.

* The doubling of speed was useful everywhere, but would be a huge advantage in textile mills, since spinning yarn demanded regular increases in the speed of rotation—as will be seen in chapter 10.

 A book entitled The Diverse and Artifactitious Machines of Captain Agostino Ramelli by a sixteenth-century Italian inventor in the employ of the Medicis contained illustrations that, whether known to Watt and Murdock or not, seem to prefigure the sun-and-planet gear.

* It also included a description of a piston-driven steam carriage that used “the elastic force of steam to give motion.” Watt had no intention of building one, for reasons that will become apparent, but he had already mastered the technique of using patents to preempt his competition.

* It also inspired one of Watt’s best-remembered inventions. In 1789, improving on an earlier device created for grain mills like Albion, he invented a centrifugal governor: two metal flyballs held in orbit around a vertical pole, linked to the power stroke of the steam engine. As the engine speeded up, centrifugal force lifted the “arms” to which the balls were connected; with a greater distance to travel with each rotation, the balls spun faster, but as they did so, they pulled down rods mounted on top of the balls and attached to the top of the pole, which in turn closed the throttle, thus slowing the engine.

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