The Knowledge: How to Rebuild Our World From Scratch

by Lewis Dartnell

  One final engineering issue arises when you have two wheels fixed on the same axle. As the car rounds a corner, the outer wheel needs to turn slightly faster than the inner, and if they are rotationally locked together both can end up slipping or dragging, making it difficult to steer and damaging the tires. A system known as the differential, an assemblage of no more than four gears, allows both wheels to be driven by the engine while turning at different rates. This ingenious device was applied in European mechanisms from 1720, and possibly dates as far back as 1000 BC in China.

  So if you peel back the skin of a brand-new sports car, something you might consider to represent the peak of modern technology, you’ll find a mishmash of components co-opted from mechanisms stretching far back through time: potter’s wheels, Roman sawmills, trip-hammers, wood lathes, and water clocks.

  The internal combustion engine is a miraculous contraption, able to transform the chemical energy latent in fuel into smooth motion, and it underlies much of transport today (alongside the jet engine for fast aircraft and the steam turbine of large ships). We’ve looked at ways to produce your own gas or liquid fuels to feed these engines, and a full fuel tank offers such a fabulously dense reservoir of energy for traveling great distances before needing resupply that combustion will surely once again play a role in long-range overland and marine transport within a post-apocalyptic society well matured in its recovery. The problem, though, is that without easily accessible crude oil the civilization after ours may well be limited in its fuel sources: the proliferation of motor vehicles from the 1920s on was enabled by the cheap availability of gasoline from oil refineries. So, what might be an alternative developmental pathway for establishing transport infrastructure in a society rebuilding from scratch?

  Rather than cultivating crops and picking out only a portion of the plant to be pressed to biodiesel or fermented to ethanol, it may be better to simply burn the whole harvest. Heating boilers to drive steam turbines and generate electricity makes a far more efficient use of the total sunlight energy captured by fast-growing biomass crops like switchgrass or miscanthus, or coppiced woodland. The electricity supply generated sustainably from biofuels as well as wind power and hydropower can be shunted down overhead wires to power trains and trams along fixed routes, or to recharge batteries for smaller vehicles. An electric car can travel farther on an acre of crop than an internal combustion engine filled with biofuel from the same harvest, and, what’s more, a boiler driving a steam turbine can be fired with far lower-grade plant matter than is required for biofuel synthesis. And if you generate that electricity in a combined heat and power (CHP) plant, you can use the waste heat to warm buildings in the vicinity. An energy-restricted post-apocalyptic society will need to use coordinated thinking to maximize the efficiency of its fuel consumption, and it seems likely that the urban transportation of a post-apocalyptic civilization will be predominantly electric.

  In fact, electric vehicles have been common once before. In the early years of the twentieth century, there were three fundamentally different automobile technologies battling for supremacy, and electric cars held their own against competition from steam- and gasoline-powered alternatives, as they are mechanically much simpler and more reliable, as well as quiet and smokeless. In Chicago they even dominated the automobile market. At the peak of production of electric vehicles in 1912, 30,000 glided silently along the streets of the USA, and another 4,000 throughout Europe; in 1918 a fifth of Berlin’s motor taxis were electric.

  The drawback of electric cars with their own onboard batteries (rather than trains or trolleys taking a continuous feed from a power line over the track) is that even a large, heavy set cannot store a great deal of energy, and once depleted the battery takes a long time to recharge. The maximum range of these early electric vehicles was around a hundred miles,* but this is farther than a horse and in an urban setting is more than adequate. The solution is, rather than waiting for the battery to be recharged, you can simply pull into a station for a quick battery pack exchange: Manhattan successfully operated a fleet of electric cabs in 1900, with a central station that rapidly swapped depleted batteries for a fresh tray.

  So with a combination of biofuel-fed internal combustion engines and electric vehicles, an advancing post-apocalyptic society will be able to provide for its transportation requirements even without the abundant oil that we benefited from in our development. Now it’s time to turn from the transport of people and materials to the conveyance of ideas: in the next chapter we’ll explore communication technologies.

  CHAPTER 10

  COMMUNICATION

  I met a traveler from an antique land

  Who said: “Two vast and trunkless legs of stone

  Stand in the desert. Near them, on the sand,

  Half sunk, a shattered visage lies, whose frown,

  And wrinkled lip, and sneer of cold command,

  Tell that its sculptor well those passions read

  Which yet survive, stamped on these lifeless things,

  The hand that mocked them and the heart that fed:

  And on the pedestal these words appear:

  ‘My name is Ozymandias, king of kings:

  Look on my works, ye Mighty, and despair!’

  Nothing beside remains. Round the decay

  Of that colossal wreck, boundless and bare,

  The lone and level sands stretch far away.”

  PERCY BYSSHE SHELLEY, “Ozymandias” (1818)

  TODAY, WITH THE INTERNET, ubiquitous wireless networks, and handheld smartphones, communication with one another anywhere in the world is effortless and instantaneous. We keep in touch via e-mail and Twitter, websites disseminate news and information, and we can access the wealth of human knowledge from the palm of our hand. But in a post-apocalyptic world you’ll need to return to more traditional communication technologies.

  WRITING

  Before the invention of writing, knowledge circulated among the minds of the living, conveyed only by the spoken word. Yet there is only so much data that can be stored in oral history, and the danger is that when people die ideas are lost forever. But once committed to a physical medium, thoughts can be stored faithfully, referred back to years later, and built up over time. A culture that has developed writing can accumulate far more knowledge than could ever be cached in the collective memories of its populace.

  Writing is one of the fundamental enabling technologies of civilization. It involves the conceptual leap of transforming spoken words into sequences of drawn shapes: either arbitrary letters representing the individual sounds of the language (such as the phonemes of English) or characters symbolizing particular objects or concepts (like the morphemes of Chinese). At the basic level, it allows you to permanently record the agreed terms of trade, a land lease, or a code of laws. But it is the accumulation of knowledge that allows a society to grow culturally, scientifically, and technologically.

  In the modern world we’ve come to take for granted such staples of civilization as pen and paper, and realize how vital they are only when we can’t simply reach for the back of an envelope to jot down a shopping list, or when we bemoan the confounding disappearance of the ballpoint we put down only two minutes ago. While plentiful paper will be left behind by our civilization, it is a particularly perishable material and will readily burn with the wildfires tearing through deserted cities or molder away with humidity and floods. How can you easily mass-produce paper for yourself, and leapfrog over the time-consuming production of other materials, such as papyrus and parchment, used historically?

  Paper was invented by the Chinese sometime around 100 AD, although it took more than a millennium to diffuse across to Europe. Paper made from tree pulp, though, is a surprisingly modern innovation. Until the late nineteenth century, paper was mainly manufactured from linen fragments, recycling tattered rags. Linen is a fabric made from fibers of the flax plant (see Chapter 4), a
nd any fibrous plants can in principle be converted into paper: hemp, nettles, rushes or other coarse grasses. But as demand grew, spurred on, as we’ll see, by the plethora of books and newspapers churned out of the printing presses, other suitable fibers were intently sought. Wood is a fabulous source of good-quality papermaking fibers, but how do you disassemble a thick, solid tree trunk into a fine soupy mush of soft, short strands without breaking your back in the process?

  The fibers that make paper so light yet strong are composed of cellulose. Chemically this is a long-chain compound used by all plants as the main structural molecule between their cells, and in particular in their stem and side shoots; it is the pithy strands of cellulose that get stuck between your teeth when you munch on celery. In the stout trunks of trees and shrubs, however, the cellulose fibers are reinforced with another structural molecule called lignin, which locks the cellulose strands together to make wood. This provides the tree with the ideal structural material for a strong, load-bearing central column and wide-spreading branches to splay its leaves out before the Sun, but it makes the cellulose fibers lamentably inaccessible to us.

  Traditionally, plant fibers were separated by crushing the stems and then retting—soaking them for several weeks in stagnant water to allow microorganisms to begin decomposing the structure—and then violently pounding the softened stalks to liberate the cellulose fibers by brute force. The good news is that you can save yourself a great deal of time and effort and leapfrog straight to a much more effective scheme.

  The links that bind together cellulose and lignin in trees are vulnerable to the chemical severing process known as hydrolysis. This is the same molecular operation that is employed in saponification during soap making, and we achieve it with exactly the same means: by rallying alkalis to the cause. The best parts of the tree or plant to use are the stem or trunk and branches—the roots and leaves don’t contain much of the cellulose fiber required. Chop the material into small pieces to expose as much surface area to the action of the solution as possible, then bathe it in a vat of boiling alkaline solution for several hours. This breaks the chemical bonds holding together the polymers, causing the plant structure to soften and fall apart. The caustic solution attacks both cellulose and lignin, but the hydrolysis of lignin is faster, allowing you to liberate the precious papermaking fibers without damage while the lignin degrades and dissolves. Short white fibers of cellulose will float to the top of the murky brown, lignin-stained broth.

  Any of the alkalis we covered in Chapter 5—potash, soda, lime—work, though the preferred option through much of history has been to use slaked lime (calcium hydroxide), as it can be generated in bulk by cooking limestone, while potash is fairly labor-intensive to produce by soaking timber ashes. But once you’ve cracked the artificial synthesis of soda (we’ll come to this in Chapter 11), the best option by far for chemical pulping is to use caustic soda (sodium hydroxide), which powerfully promotes hydrolysis. You generate this directly in the pulping vat by mixing together slaked lime and soda.

  Collect the recovered cellulose fibers in a sieve and then rinse several times until they run clear of the mucky lignin color. To lighten the shade of the finished paper to a clean white, you can also soak the pulp in bleach at this point. Calcium hypochlorite or sodium hypochlorite are both effective bleaching agents, and can be created by reacting chlorine gas (produced electrolytically from seawater) with slaked lime or caustic soda, respectively. The chemistry behind this bleaching effect is oxidation: bonds in the colored compounds are broken to destroy the molecule or convert it to an uncolored form. Bleaching is critical not only to papermaking, but also to textile production, so it will likely be a key driving force for expanding the chemical industry during a reboot.

  Pour a dollop of this sloppy cellulose soup across a fine wire mesh or cloth screen, bounded on the sides by a frame, so that the fibers form a higgledly-piggledy mat as the water drains out. You then press it to squeeze out the remaining water and to ensure flat, smooth sheets of paper, and leave to dry.

  You’ll find small-scale paper production much easier if you’re able to scavenge a few items from the fallen civilization. A wood chipper or even a large food processor, powered from a generator, will make lighter work of the chewing up of plant matter into a thick vegetative soup: but you can also let windmills or watermills provide the mechanical brawn needed for driving trip-hammers to pound the material.

  However, creating clean, smooth paper is only half of the solution to being able to use writing for communication and recording permanent stores of knowledge. The other critical task, once all of the remnant ballpoints have dried up or disappeared, is to make your own reliable ink with which to form the written word.

  In principle, anything that irritatingly stains your cotton shirt if you accidentally splash yourself can also be used as a makeshift ink. You can take a handful of intensely colored ripe berries, for example, and crush them to release their juice, strain to remove the mashed fruit pulp, and dissolve in some salt to serve as a preservative. The major problem with most plant extract inks, though, is their impermanence. To preserve your words and the recovering society’s newly accumulated knowledge indefinitely, you really want an ink that won’t readily wash off the page or fade in sunlight. The solution that emerged in medieval Europe is known as iron gall ink. In fact, the history of Western civilization itself was written in iron gall ink. Leonardo da Vinci wrote his notebooks with it. Bach composed his concertos and suites with it. Van Gogh and Rembrandt sketched with it. The Constitution of the United States of America was committed to posterity with it. And a formulation very similar to the original iron gall ink is still in widespread use in Britain today: registrar’s ink, required to be used for legal documents such as birth, death, and marriage certificates, uses exactly the same medieval chemistry.

  As the name reveals, the recipe for iron gall ink contains two main ingredients: an iron compound and an extract from plant galls. Galls appear on the branches of trees such as oak, and are formed when parasitic wasps lay their eggs in the leaf bud and irritate the tree into forming a growth around it. They are rich in gallic and tannic acids, which react with iron sulfate—created by dissolving iron in sulfuric acid. Iron gall ink is practically colorless when first mixed, and so it’s difficult to see where you’re writing unless another plant dye is also included. But with exposure to the air, the iron component oxidizes to turn the dry ink a deep, enduring black.

  A rudimentary pen can also be made in the time-honored fashion. Soak a bird’s feather (goose or duck was preferred historically) in hot water and pull out the material within the shaft. Bring the tip into a sharp point by cutting into each side, and then undercut the bottom face into a gentle curve to create the classic shape of a writing nib. Slitting backward slightly into the pointed tip will allow the nib to hold a tiny reservoir of ink as you write, between replenishing dunks into the inkwell.

  PRINTING

  If writing is the critical development to enable the permanent storage and accumulation of ideas, then the printing press is the machine for the rapid replication and extensive dispersal of human thought. Today, the developed world boasts near-universal literacy, and an estimated 45 trillion pages are printed every day: books, newspapers, magazines, and pamphlets.

  Without printing, if you wanted a document reproduced it would take a dedicated team of scribes arduously copying it by hand for weeks. Hence only the powerful and well resourced would be able to afford the project, which also means only approved or endorsed texts are propagated. But with the dissolution of such a choke point, thanks to the printing press, knowledge becomes democratized. Not only does learning become available to everyone in society, but anyone can rapidly disseminate their own ideas, from new scientific theories to radical political ideologies, encouraging debate and promoting change.

  The basic principle of printing is that a page of writing is re-created as rows of types—cuboidal blocks, eac
h with a letter embossed on the top face—arranged within a rectangular frame. The type is inked and then pressed onto a sheet. Once the frame has been typeset, the same page of text can be replicated again and again exceedingly quickly, and when done, the letters are simply rearranged into another page of text. Even a rudimentary printing press can reproduce a document hundreds of times faster than a scribe.

  There are three major challenges that you’ll need to solve for a post-apocalyptic resurrection of the movable-type printing press, which Johannes Gutenberg invented in fifteenth-century Germany.* You’ll need to find a way to easily produce large numbers of precisely sized types. You’ll also need to devise a mechanism to provide an even but firm pressure to apply the print to the page. And third, you’ll need to invent a new kind of ink that doesn’t flow freely from a pen nib, but sticks well to intricate metallic detail.

  The first issue you’re faced with is what material you use to make the types. Wood can be carved easily, but this would necessitate the diligent work of a skilled craftsman to hand-make each and every piece of type individually—around eighty letters (both lowercase and capitals), numbers, punctuation marks, and other common symbols—and then produce multiple, identical copies of each. And all that hard work for just a single set of type, in only one font size and one style.

  So in order to mass-produce printed books, you must first mass-produce the tools for printing. This can be achieved by type casting: founding identical letter blocks with molten metal. The solution for creating types with straight, smooth sides and perfect right-angle edges that slot perfectly alongside each other in rows, Gutenberg realized, is to cast the types in a metal mold with a sharp cuboidal interior void. Cleverly, the crisp shape of a particular letter can be formed on the end face of the block by positioning a swappable matrix at the bottom of the mold. These matrices can be made from a soft metal such as copper, and the precise indent of a letter hammered into each of them very simply with a hard steel punch. Now all you have to do is engrave each letter, number, or symbol just once onto different punches, and you can effortlessly churn out countless pieces of identical type.