Exactly: How Precision Engineers Created the Modern World. Simon Winchester

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СКАЧАТЬ the beam tilted, and a small amount of work (a very small amount) could be performed by whatever was on the far end of the beam.

      Newcomen then realized he could increase the work by injecting cold water into the steam-filled cylinder, condensing the steam and bringing it back to 1/1,700 of its volume—creating, in essence, a vacuum, which enabled the pressure of the atmosphere to force the piston back down again. This downstroke could then lift the far end of the rocker beam and, in doing so, perform real work. The beam could lift floodwater, say, out of a waterlogged tin mine.

      Thus was born a very rudimentary kind of steam engine, almost useless for any application beyond pumping water, but given that early eighteenth-century England was awash with shallow mines that were themselves awash with water, the mechanism proved popular and useful to the colliery community. The Newcomen engine and its like remained in production for more than seventy years, its popularity beginning to lessen only in the mid-1760s, when James Watt, who was then employed making and repairing scientific instruments six hundred miles away at the University of Glasgow, studied a model of its workings closely and decided, in a series of moments of the purest genius, that it could be markedly improved. It could be made efficient, he thought. It could possibly be made extremely powerful.

      And it was John Wilkinson who helped to make it so—once, that is, Watt had had his strokes of the purest genius. These can be summed up simply enough. For weeks, alone in his rooms in Glasgow, Watt puzzled over a model of the Newcomen engine, a machine famed for being so woefully inadequate, so inefficient, so wasteful of all the heat and energy expended upon it. Watt, patiently trying out various ways to improve on Newcomen’s invention, is reported to have remarked wearily that “Nature has a weak side, if only we can find it out.”

      He finally did so, according to legend, one Sunday in 1765, as he was taking a restorative walk through a park in central Glasgow. He realized that the central inefficiency of the engine he was examining was that the cooling water injected into the cylinder to condense the steam and produce the vacuum also managed to cool the cylinder itself. To keep the engine running efficiently, though, the cylinder needed to be kept as hot as possible at all times, so the cooling water should perhaps condense the steam not in the cylinder but in a separate vessel, keeping the vacuum in the main cylinder, which would thus retain the cylinder’s heat and allow it to take on steam once more. Moreover, to make matters even more efficient, the fresh steam could be introduced at the top of the piston rather than the bottom, with stuffing of some sort placed and packed into the cylinder around the piston rod to prevent any steam from leaking out in the process.

      These two improvements (the inclusion of a separate steam condenser and the changing of the inlet pipes to allow for the injection of new steam into the upper rather than the lower part of the main cylinder)—improvements so simple that, at this remove, they seem obvious, even though, to James Watt in 1765, they were anything but—changed Newcomen’s so-called fire-engine into a proper and fully functioning steam-powered machine. It became in an instant a device that in theory could produce almost limitless amounts of power.

      

       A cross section of a late eighteenth-century Boulton and Watt steam engine. The main cylinder, C, would have been bored by John Wilkinson, the piston, P, fitting snugly inside it to the thickness of an English shilling, a tenth of an inch.

      As he began what would be a full decade of testing and prototype building and demonstrating and seeking funds (during which time he moved south from Scotland to the vibrantly industrializing purlieus of the English Midlands), Watt sought and was swiftly awarded a patent: Number 913 of January 1769. It had a deceptively innocuous title: “A New Invented Method of Lessening the Consumption of Steam and Fuel in Fire-Engines.” The modest wording belies the invention’s importance: once perfected, it was to be the central power source for almost all factories and foundries and transportation systems in Britain and around the world for the next century and more.

      What is especially and additionally noteworthy, though, is that a historic convergence was in the making. For, living and working nearby in the Midlands, and soon to produce a patent himself (the already noted Number 1063 of January 1774, an exact one hundred fifty patents and exactly five years later than James Watt’s), was no less an inventor than John Wilkinson, ironmaster.

      By then, Wilkinson’s amiable madness was making itself felt throughout the ferrous community: all came to learn that he had made an iron pulpit from which he lectured, an iron boat he floated on various rivers, an iron desk, and an iron coffin in which he would occasionally lie and make his frightening mischief. (Women were in plentiful attendance, despite his being a somewhat unattractive man with a massively pockmarked face. He had a vigorous sex drive, fathering a child at seventy-eight by way of a maidservant, a calling of which he was inordinately fond. He kept a seraglio of three such women at one time, each one unaware of the others.)

      Still, Wilkinson could and would free himself from these distractions, and by 1775, he and Watt, though of very different temperaments, had met and befriended each other, though it was a friendship based more on commerce than affection. Before long, their two inventions were, and to their mutual commercial benefit, commingled. Wilkinson’s “New Method of Casting and Boring Iron Guns or Cannon” was married to Watt’s “New Invented Method of Lessening the Consumption of Steam and Fuel in Fire-Engines.” It was a marriage, it turned out, of both convenience and necessity.

      James Watt, a Scotsman renowned for being pessimistic in outlook, pedantic in manner, scrupulous in affect, and Calvinist in calling, was obsessed with getting his machinery as right as it could possibly be. While he was making and repairing and improving the scientific instruments in his workshop in Glasgow, he became well-nigh immured by his passion for exactitude, to much the same degree as had John Harrison in his clock-making workshop in Lincolnshire. Watt was quite familiar with the early dividing engines and screw thread cutters and lathes and other instruments that were then helping engineers take their first tentative steps toward machine perfection. He was accustomed to instruments that were carefully built and properly maintained, and that worked as they were intended to. He was mortally offended, then, when things went wrong, when inefficiencies were compounded, and when the monster iron engines he was now trying to build in the giant Boulton and Watt factory in Soho performed less well than the brass-and-glass models on which he had experimented back up in Scotland.

      His first prototype large engines were spectacular behemoths: thirty feet tall, with a main steam cylinder four feet in diameter and six feet long, a coal-fired boiler, and a separate steam condenser, all massive. All the working parts were connected by a convoluted spiderweb of brass pipes and well-oiled valves and levers, with a spinning two-ball governor that prevented runaways. Above it all was a heavy wooden beam that rocked back and forth with metronomic regularity, turning a huge iron flywheel that in turn worked a pump that gushed water or compressed air or performed other tasks fifteen times a minute. Once at full power, the engine produced a concatenation of noise and heat and a juddering, thudding, stomach-churning intensity that somehow seemed an impossible consequence of merely heating water up to its natural boiling point.

      Yet everywhere, perpetually enveloping his engine in a damp, hot, opaque gray fog, were billowing clouds of steam. It was this, this scorching miasma of invisibility, that incensed the scrupulous and pedantic James Watt. Try as he might, do as he could, steam always seemed to be leaking, and doing so not stealthily but in prodigious gushes, and most impudently of all, it was doing so from the engine’s enormous main cylinder.

      He tried blocking the leak with all kinds of devices, things, and substances. The gap between the piston’s outer surface and the cylinder’s inner wall should, in theory, have been minimal, and more or less the same wherever it was measured. But because the cylinders were made of iron sheets hammered СКАЧАТЬ