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 b.a.l.l.s 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 c.o.ke 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 antic.i.p.ating 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 good"47 (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 ill.u.s.trates 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 ab.u.t.ted the same Temple Bar where Edward c.o.ke 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 Ca.n.a.l.
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 ent.i.tled The Diverse and Artifact.i.tious Machines of Captain Agostino Ramelli by a sixteenth-century Italian inventor in the employ of the Medicis contained ill.u.s.trations 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 compet.i.tion.
* 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 flyb.a.l.l.s 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 b.a.l.l.s were connected; with a greater distance to travel with each rotation, the b.a.l.l.s spun faster, but as they did so, they pulled down rods mounted on top of the b.a.l.l.s and attached to the top of the pole, which in turn closed the throttle, thus slowing the engine.
CHAPTER NINE.
QUITE SPLENDID WITH A FILE.
concerning the picking of locks; the use of wood in the making of iron, and iron in the making of wood; the very great importance of very small errors; blocks of all shapes and sizes; and the tool known as "the Lord Chancellor"
THE SHOP WAS SLIGHTLY off the most traveled portion of Piccadilly, across from Green Park near Half Moon Street, but hundreds, if not thousands, of pedestrians still walked past it every day. Which meant that every day during the spring of 1801, thousands of eyes saw the challenge. It was hung in the store"s window, incised on a bra.s.s contraption the shape of an oversized acorn, and read: THE ARTIST.
WHO CAN MAKE AN.
INSTRUMENT1 THAT WILL PICK.
OR OPEN THIS LOCK SHALL.
RECEIVE 200 GUINEAS.
THE MOMENT.
IT IS PRODUCED.
APPLICATIONS IN WRITING ONLY.
At the top of the acorn, in place of the cupule that attaches the nut to its tree, was the lock in question. At its bottom was the legend: CAUTION.
THE PUBLIC IS RESPECTFULLY INFORMED.
THAT EVERY LOCK MADE BY.
BRAMAH & Co IS STAMPED
WITH THEIR ADDRESS.
124 PICCADILLY.
As gimmicks go, this was one of the more successful in the history of marketing.* But its object was no gimmick: the "challenge lock," designed to be opened by a tubular key incised with slots along the long axis, would defy all challenges for fifty years. Different models were on offer almost from the beginning, containing as few as five sliders or as many as fourteen. That was the number contained in the "challenge lock," giving it potentially 470 million possible combinations and making it virtually unpickable. Indeed, it remained unpicked until 1851, when an American locksmith finally succeeded at the Great London Exposition, supposedly taking more than fifty hours in the process. The challenge lock was such a remarkable bit of technological brilliance that an updated version of the same design is still sold by the same firm, now known as Bramah UK. Its managing director, Jeremy Bramah, is a direct descendant of the firm"s founder, Joseph Bramah, and it is no coincidence that his original lock is on display at London"s Science Museum only yards away from Rocket.
JOSEPH BRAMAH, THE SON of a Yorkshire farmer, had been apprenticed to a cabinetmaker named Joseph Allott in 1765 when he was sixteen years old, but it took another thirteen years for him to get his first patent, for a flush toilet with a floating ball and flap valve designed to prevent it from seizing up during freezing weather. It was not only an immediate success, with thousands installed across Britain, but is still recognizably the system used in most modern water closets.
Bramah may have been a late bloomer, but during the last twenty years of his life he would become an inventing phenomenon, creating dozens of highly profitable machines for the widest possible range of applications. He was also, from 1783 on, a member of the British Society of Arts, which, it will be recalled, was enthusiastic about giving prizes for inventions but opposed patenting them until the middle of the nineteenth century. One can only imagine the debates that must have been prompted by Bramah"s presence, since, in a remarkable stretch starting in 1793, he patented more than eighteen separate machines, including a fire engine; the first hydraulic press, which applied the principle of feedback in the form of a self-tightening collar to prevent fluid loss; the first beer tap (apparently designed to save publicans from carrying barrels up and down stairs); a wood-planing machine that used twenty-eight tools mounted on a vertical shaft, one of which was still in use thirty years after Bramah"s patent expired; and a machine for numbering and dating banknotes (the Bank of England would order three dozen of the machines).
Woodworking and fine cabinetry, however, were Bramah"s original sources of income, and apparently his primary source of insecurity, since he spent at least three years working on a new method of locking his workshop for the night. He received his first lock patent in 1784, for "a LOCK, constructed on a new and infallible Principle,2 which, possessing all the Properties essential to Security, will prevent the most ruinous Consequences of HOUSE ROBBERIES, and be a certain Protection."
The lock made Bramah"s fortune. London"s upper cla.s.ses were, with a good deal of justification, fearful of theft, and thus prepared to pay the equivalent of a laborer"s annual salary for an unpickable lock. His marketing brilliance and intuitive understanding of branding meant that people also valued the status conferred by ownership; several decades later Charles d.i.c.kens made a point of reminding his readers that the Gray"s Inn offices of Mr. Perker, the "cautious little" attorney in The Pickwick Papers, were secured by a Bramah lock.
However, the secret to its obduracy was a highly complicated design requiring up to a hundred separate metal pieces, each of which needed to be made to extremely accurate tolerances, and producing even the simplest Bramah locks in anything approaching the quant.i.ty demanded presented huge technical difficulties. This was a central challenge of this period of frantic invention: how to produce complicated machines in quant.i.ty.
The combination was the problem. Navigational instruments, and especially clocks and watches, were already made not only precisely, but identically; however, their market was small enough to be met on a bespoke basis. "Machines" such as buckles and millstones could be produced in bulk, but had few moving parts and a lot of room for error.
Two developments were needed to turn the custom-made machine into one that could be manufactured in quant.i.ty. Darby, Huntsman, Cort, and their compet.i.tors had tackled the first part of the problem by producing a regular supply of iron, an affordable material that could be fabricated into as many shapes as wood, but unlike wood would keep its shape even when abraded or stressed. The second was some way to turn that iron into shapes precisely and consistently. If the most important invention of the Industrial Revolution was invention itself, the automation of precision has to be one of the top three.
Appropriately enough, the development can be dated with a reasonable amount of accuracy, to the day in 1789 that the forty-year-old Bramah first met an eighteen-year-old metalworking prodigy from the Royal a.r.s.enal at Woolwich named Henry Maudslay.
MAUDSLAY WAS BORN AT Woolwich, where his father was employed as a laborer making munitions for the Royal Navy, and soon enough the a.r.s.enal offered employment to Henry as well, who became a "powder monkey" loading gunpowder into sh.e.l.ls at the age of twelve. From subsequent events, we can safely a.s.sume that he was not only clever with his hands-on the sly, he forged highly prized kitchen implements for families throughout Woolwich-but careful as well, since he was in full possession of all his fingers when he left Woolwich for London six years later.
The lock design was then five years old, but the need for handcrafting made it more of a curiosity than a commercial success. Bramah was well aware of the problem, and he sought a solution from London"s best-regarded blacksmith, a German named William Moodie. Moodie was stumped, but he had heard some of the legends that were already forming around Maudslay at Woolwich and recommended him to Bramah, who satisfied himself that the onetime powder monkey was not only resourceful, but even more fanatical about precision than he was himself.
Satisfying that mania for precision wasn"t particularly easy in the last decades of the eighteenth century. Despite the enormous number of innovations that had appeared over the preceding eighty years, at the moment when Bramah met Maudslay, the most critical precision instrument in the heavy metal trades remained a good file; a diligent metalworker was still measured by his ability to take the rough edges off everything from a pocket watch"s winding screw to the turnscrew on a one-ton cannon.
The screw is one of the canonical simple machines, along with the lever, wedge, and inclined plane, with a history dating back to the Fertile Crescent, and throughout antiquity wood screws were used as presses for oil, wine, and (by the time of the Inquisition) the occasional human thumb. Yet Maudslay sensed that the screw, despite its antiquity and simplicity, was also the tool of the future. For centuries, screws had been produced using the hand tools known as taps and dies: the former to cut interior threads-the "female" side-and the latter the exterior, or "male," threads. But until the fifteenth century, almost all of them were cut out of wood, which didn"t do much for either their precision or their durability. Even when European metalworkers started to make metal screws, their dependence on hand tools required that the metal be relatively soft-and, more important, kept the screws rare. Until screws, and other sym-metrical metal objects, could be made by a machine, they were destined to stay that way.
The machine that finally broke the logjam-the lathe-was nearly as old as the screw. It had evolved considerably during the preceding two millennia, from the Egyptian "rope bow" operated by a person pulling back and forth on a rope attached to the workpiece, to the Roman bow lathe, and finally to the spring-operated pole lathe, which represented the state of the art in wood turning from about the first century CE through the Middle Ages.
Wood turning has its own satisfactions. As anyone who has ever taken what used to be called shop cla.s.s will recall, there is a beauty in watching a lathe (or its close cousin, a potter"s wheel) at work. The transformation of an irregular shape into a symmetrical one seems to feed what may be a universal love of harmony, and even the simplest lathe work-turning a block of wood into a chair leg or a baseball bat-is satisfying to watch, and even more satisfying to do. But it is limiting. The lathe remained a tool for creating only beauty until the sixteenth century, when it finally became a tool for creating other tools-and, most particularly, a tool for creating metal screws.
That was when the onetime wood turning machines acquired the mandrel-a spindle onto which the workpiece was attached, thereby transmitting rotation to the spindle rather than to the piece itself. Even more important, the sixteenth-century lathes finally started using the long leadscrew, which moved the workpiece horizontally as it was rotated. The leadscrew, combined with a steady platform for the cutting tool, was now the measure of precision in lathe work: Any piece turned on a lathe that used a leadscrew could be made as precisely as the leadscrew itself.
Using a leadscrew made any lathe work more precise, but its really revolutionary application emerged when a number of innovators figured out how to angle the cutting head to incise a continuous helical groove onto a smooth cylinder: to machine a screw. And not just a screw fastener; the reason lathes are frequently called history"s "first self-replicating machines" is that, beginning in the sixteenth century, they were used to produce their own leadscrews. A dozen inventors from all over Europe, including the Huguenots Jacques Besson and Salomon de Caus, the Italian clockmaker Torriano de Cremona, the German military engineer Konrad Keyser, and the Swede Christopher Polhem, mastered the iterative process by which a lathe could use one leadscrew to cut another, over and over again, each time achieving a higher order of accuracy. By connecting the lathe spindle and carriage to the leadscrew, the workpiece could be moved a set distance for every revolution of the spindle; if the workpiece revolved eight times while the cutting tool was moved a single inch, then eight spiral grooves would be cut on the metal for every inch: eight turns per inch.
Thus a leadscrew that was accurate to within could operate a lathe that could cut a new screw accurate to within 716, and the new leadscrew could in turn produce one accurate to within , eventually achieving a very high degree of precision.
Not, however, high enough for Bramah"s locks. For while the leadscrews on those lathes were made of iron, most of the lathe"s other components were made of wood. And wood, even very hard wood, shakes. It shakes enough, in fact, that even the sharpest steel blade couldn"t make a cut accurate to within 116-an enormous error margin in a three-inch lock.
Henry Maudslay"s first, and probably greatest, contribution to the Bramah Lock Co., and to the Industrial Revolution, was his realization of the huge advantages of a lathe made entirely of iron. Not just the leadscrew and the slide rest-a platform that holds the tool post and moves the tool laterally as precisely as the leadscrew moved the workpiece horizontally-but all the platforms, bits, and supports of the lathe. Maudslay"s design integrated all of them in a manner that achieved a degree of precision greater than any could offer individually. The advantage of iron over wood turned out to be critical.
Maudslay"s perception about the superiority of iron may have come to him in the form of a Glasgow Green sort of insight, but he left no diary that would confirm its origin, or even precisely when he produced the first all-iron lathe for Bramah, though it was certainly in operation by 1791. During the 1790s, Maudslay"s key insight-that stability equaled precision, and iron was stable-was incorporated into a number of other tools he built for Bramah"s lock business, including drills, planing machines, and possibly even a rotary file: essentially one of the first mechanical milling machines, used to shape metal into nonsymmetrical shapes, just as lathes formed them into symmetrical ones. In addition, he is credited with inventing a self-tightening leather collar that made Bramah"s hydraulic press a working proposition.
However, Bramah was in the business of selling locks, not lathes, and he determined that the best business decision was to patent the things made by his new machine tools, not the tools themselves, which he kept secret as long as possible; as a result, it is rather difficult to doc.u.ment when, precisely, Maudslay and Bramah put them on the company"s production line. No such problem exists in doc.u.menting Maudslay"s devotion to his employer, which was far greater than his employer had for him. Even when Bramah promoted Maudslay3 to shop superintendent in 1798, he was still paying him a fairly modest thirty shillings a week, which was not enough for Maudslay"s growing family. Unable to persuade Bramah4 to part with a living wage, Maudslay left and set up shop on Oxford Street in London, where he was employing eighty men by 1800, and nearly two hundred by 1810.