How We Got to Now: Six Innovations That Made the Modern World

by Steven Johnson

  Part of the beauty of ice, of course, was that it was basically free: Tudor needed only to pay workers to carve blocks of it out of the frozen lakes. New England’s economy generated another product that was equally worthless: sawdust—the primary waste product of lumber mills. After years of experimenting with different solutions, Tudor discovered that sawdust made a brilliant insulator for his ice. Blocks layered on top of each other with sawdust separating them would last almost twice as long as unprotected ice. This was Tudor’s frugal genius: he took three things that the market had effectively priced at zero—ice, sawdust, and an empty vessel—and turned them into a flourishing business.

  Tudor’s initial catastrophic trip to Martinique had made it clear that he needed on-site storage in the tropics that he could control; it was too dangerous to keep his rapidly melting product in buildings that weren’t specifically engineered to insulate ice from the summer heat. He tinkered with multiple icehouse designs, finally settling on a double-shelled structure that used the air between two stone walls to keep the interior cool.

  Tudor didn’t understand the molecular chemistry of it, but both the sawdust and the double-shelled architecture revolved around the same principle. For ice to melt, it needs to pull heat from the surrounding environment to break the tetrahedral bonding of hydrogen atoms that gives ice its crystalline structure. (The extraction of heat from the surrounding atmosphere is what grants ice its miraculous capacity to cool us down.) The only place that heat exchange can happen is at the surface of the ice, which is why large blocks of ice survive for so long—all the interior hydrogen bonds are perfectly insulated from the exterior temperature. If you try to protect ice from external warmth with some kind of substance that conducts heat efficiently—metal for instance—the hydrogen bonds will break down quickly into water. But if you create a buffer between the external heat and the ice that conducts heat poorly, the ice will preserve its crystalline state for much longer. As a thermal conductor, air is about two thousand times less efficient than metal, and more than twenty times less efficient than glass. In his icehouses, Tudor’s double-shelled structure created a buffer of air that kept the summer heat away from the ice; his sawdust packaging on the ships ensured that there were countless pockets of air between the wood shavings to keep the ice insulated. Modern insulators such as Styrofoam rely on the same technique: the cooler you take on a picnic keeps your watermelon chilled because it is made of polystyrene chains interspersed with tiny pockets of gas.

  By 1815, Tudor had finally assembled the key pieces of the ice puzzle: harvesting, insulation, transport, and storage. Still pursued by his creditors, he began making regular shipments to a state-of-the-art icehouse he had built in Havana, where an appetite for ice cream had been slowly maturing. Fifteen years after his original hunch, Tudor’s ice trade had finally turned a profit. By the 1820s, he had icehouses packed with frozen New England water all over the American South. By the 1830s, his ships were sailing to Rio and Bombay. (India would ultimately prove to be his most lucrative market.) By his death in 1864, Tudor had amassed a fortune worth more than $200 million in today’s dollars.

  Three decades after his first failed voyage, Tudor wrote these lines in his journal:

  This day I sailed from Boston thirty years ago in the Brig Favorite Capt Pearson for Martinique: with the first cargo of ice. Last year I shipped upwards of 30 cargoes of Ice and as much as 40 more were shipped by other persons… . The business is established. It cannot be given up now and does not depend upon a single life. Mankind will have the blessing for ever whether I die soon or live long.

  Tudor’s triumphant (if long-delayed) success selling ice around the world seems implausible to us today not just because it’s hard to imagine blocks of ice surviving the passage from Boston to Bombay. There’s an additional, almost philosophical, curiosity to the ice business. Most of the trade in natural goods involves material that thrives in high-energy environments. Sugarcane, coffee, tea, cotton—all these staples of eighteenth-and nineteenth-century commerce were dependent on the blistering heat of tropical and subtropical climates; the fossil fuels that now circle the planet in tankers and pipelines are simply solar energy that was captured and stored by plants millions of years ago. You could make a fortune in 1800 by taking things that grew only in high-energy environments and shipping them off to low-energy climates. But the ice trade—arguably for the only time in the history of global commerce—reversed that pattern. What made ice valuable was precisely the low-energy state of a New England winter, and the peculiar capacity of ice to store that lack of energy for long periods of time. The cash crops of the tropics caused populations to swell in climates that could be unforgivingly hot, which in turn created a market for a product that allowed you to escape the heat. In the long history of human commerce, energy had always correlated with value: the more heat, the more solar energy, the more you could grow. But in a world that was tilting toward the productive heat of sugarcane and cotton plantations, cold could be an asset as well. That was Tudor’s great insight.

  —

  IN THE WINTER OF 1846, Henry Thoreau watched ice cutters employed by Frederic Tudor carve blocks out of Walden Pond with a horse-drawn plow. It might have been a scene out of Brueghel, men working in a wintry landscape with simple tools, far from the industrial age that thundered elsewhere. But Thoreau knew their labor was attached to a wider network. In his diaries, he wrote a lilting reverie on the global reach of the ice trade:

  Thus it appears that the sweltering inhabitants of Charleston and New Orleans, of Madras and Bombay and Calcutta, drink at my well… . The pure Walden water is mingled with the sacred water of the Ganges. With favoring winds it is wafted past the site of the fabulous islands of Atlantis and the Hesperides, makes the periplus of Hanno, and, floating by Ternate and Tidore and the mouth of the Persian Gulf, melts in the tropic gales of the Indian seas, and is landed in ports of which Alexander only heard the names.

  If anything, Thoreau was underestimating the scope of that global network—because the ice trade that Tudor created was about much more than frozen water. The blank stares that had confronted Tudor’s first shipment of ice to Martinique slowly but steadily gave way to an ever widening dependence on ice. Ice-chilled drinks became a staple of life in southern states. (Even today, Americans are far more likely to enjoy ice with their beverages than Europeans, a distant legacy of Tudor’s ambition.) By 1850, Tudor’s success had inspired countless imitators, and more than a hundred thousand tons of Boston ice were shipped around the world in a single year. By 1860, two out of three New York homes had daily deliveries of ice. One contemporary account describes how tightly bound ice had become to the rituals of daily life:

  In workshops, composing rooms, counting houses, workmen, printers, clerks club to have their daily supply of ice. Every office, nook or cranny, illuminated by a human face, is also cooled by the presence of his crystal friend… . It is as good as oil to the wheel. It sets the whole human machinery in pleasant action, turns the wheels of commerce, and propels the energetic business engine.

  Ice blocks being cut from a lake are floated in water, then up a runway to a storage house, 1950.

  The dependence on natural ice became so severe that every decade or so an unusually warm winter would send the newspapers into a frenzy with speculation about an “ice famine.” As late as 1906, the New York Times was running alarming headlines: “Ice Up To 40 Cents And A Famine In Sight.” The paper went on to provide some historical context: “Not in sixteen years has New York faced such an iceless prospect as this year. In 1890 there was a great deal of trouble and the whole country had to be scoured for ice. Since then, however, the needs for ice have grown vastly, and a famine is a much more serious matter now than it was then.” In less than a century, ice had gone from a curiosity to a luxury to a necessity.

  Ice-powered refrigeration changed the map of America, nowhere more so than in the transformation of Chicago. Chicago’s initial burst of growth had come afte
r the nexus of canals and rail lines connected the city to both the Gulf of Mexico and the cities of the eastern seaboard. Its fortuitous location as a transportation hub—created both by nature and some of the most ambitious engineering of the century—enabled wheat to flow from the bountiful plains to the Northeast population centers. But meat couldn’t make the journey without spoiling. Chicago developed a large trade in preserved pork starting in the middle of the century, with the first stockyards slaughtering the hogs on the outskirts of the city before sending the goods east in barrels. But fresh beef remained largely a local delicacy.

  But as the century progressed, a supply/demand imbalance developed between the hungry cities of the Northeast and the cattle of the Midwest. As immigration fueled the population of New York and Philadelphia and other urban centers in the 1840s and 1850s, the supply of local beef failed to keep up with the surging demand in the growing cities. Meanwhile, the conquest of the Great Plains had enabled ranchers to breed massive herds of cattle, without a corresponding population base of humans to feed. You could ship live cattle by train to the eastern states to be slaughtered locally, but transporting entire cows was expensive, and the animals were often malnourished or even injured en route. Almost half would be inedible by the time they arrived in New York or in Boston.

  Two young boys watch two icemen make a delivery on a Harlem sidewalk, 1936.

  It was ice that ultimately provided a way around this impasse. In 1868, the pork magnate Benjamin Hutchinson built a new packing plant, featuring “cooling rooms packed with natural ice that allowed them to pack pork year-round, one of the principal innovations in the industry,” according to Donald Miller, in his history of nineteenth-century Chicago, City of the Century. It was the beginning of a revolution that would transform not only Chicago but the entire natural landscape of middle America. In the years after the fire of 1871, Hutchinson’s cooling rooms would inspire other entrepreneurs to integrate ice-cooled facilities to the meatpacking trade. A few began transporting beef back east in open-air railcars during winter, relying on the ambient temperature to keep the steaks cold. In 1878, Gustavus Franklin Swift hired an engineer to build an advanced refrigerator car, designed from the ground up to transport beef to the eastern seaboard year round. Ice was placed in bins above the meat; at stops along the route, workers could swap in new blocks of ice from above, without disturbing the meat below. “It was this application of elementary physics,” Miller writes, “that transformed the ancient trade of beef slaughtering from a local to an international business, for refrigerator cars led naturally to refrigerator ships, which carried Chicago beef to four continents.” The success of that global trade transformed the natural landscape of the American plains in ways that are still visible today: the vast, shimmering grasslands replaced by industrial feedlots, creating, in Miller’s words, “a city-country [food] system that was the most powerful environmental force in transforming the American landscape since the Ice Age glaciers began their final retreat.”

  The Chicago stockyards that emerged in the last two decades of the nineteenth century were, as Upton Sinclair wrote, “the greatest aggregation of labor and capital ever gathered in one place.” Fourteen million animals were slaughtered in an average year. In many ways, the industrial food complex held in such disdain by modern-day “slow food” advocates begins with the Chicago stockyards and the web of ice-cooled transport that extended out from those grim feedlots and slaughterhouses. Progressives like Upton Sinclair painted Chicago as a kind of Dante’s Inferno of industrialization, but in reality, most of the technology employed in the stockyards would have been recognizable to a medieval butcher. The most advanced form of technology in the whole chain was the refrigerated railcar. Theodore Dreiser got it right when he described the stockyard assembly line as “a direct sloping path to death, dissection, and the refrigerator.”

  The conventional story about Chicago is that it was made possible thanks to the invention of the railroad and the building of the Erie Canal. But those accounts tell only part of the story. The runaway growth of Chicago would have never been possible without the peculiar chemical properties of water: its capacity for storing and slowly releasing cold with only the slightest of human interventions. If the chemical properties of liquid water had somehow turned out to be different, life on earth would have taken a radically different shape (or more likely, would not have evolved at all). But if water hadn’t also possessed its peculiar aptitude for freezing, the trajectory of nineteenth-century America would have almost certainly been different as well. You could send spices around the globe without the advantages of refrigeration, but you couldn’t send beef. Ice made a new kind of food network imaginable. We think of Chicago as a city of broad shoulders, of railroad empires and slaughterhouses. But it is just as true to say that it was built on the tetrahedral bonds of hydrogen.

  —

  IF YOU WIDEN YOUR FRAME of reference, and look at the ice trade in the context of technological history, there is something puzzling, almost anachronistic, about Tudor’s innovation. This was the middle of the nineteenth century, after all, an era of coal-powered factories, with railroads and telegraph wires connecting massive cities. And yet the state of the art in cold technology was still entirely based on cutting chunks of frozen water out of a lake. Humans had been experimenting with the technology of heat for at least a hundred thousand years, since the mastery of fire—arguably Homo sapiens’ first innovation. But the opposite end of the thermal spectrum was much more challenging. A century into the industrial revolution, artificial cold was still a fantasy.

  But the commercial demand for ice—all those millions of dollars flowing upstream from the tropics to the ice barons of New England—sent a signal out across the world that there was money to be made from cold, which inevitably sent some inventive minds off in search of the next logical step of artificial cold. You might assume Tudor’s success would inspire a new generation of equally mercenary entrepreneur-inventors to create the revolution in man-made refrigeration. Yet, however much we may celebrate the start-up culture of today’s tech world, essential innovations don’t always come out of private-sector exploration. New ideas are not always motivated, like Tudor’s, by dreams of “fortunes larger than we shall know what to do with.” The art of human invention has more than one muse. While the ice trade began with a young man’s dream of untold riches, the story of artificial cold began with a more urgent and humanitarian need: a doctor trying to keep his patients alive.

  It’s a story that begins at the scale of insects: in Apalachicola, Florida, a town of ten thousand people living alongside a swamp in a subtropical climate—the perfect environment for breeding mosquitoes. In 1842, abundant mosquitoes meant, inevitably, the risk of malaria. At the modest local hospital, a doctor named John Gorrie sat helpless as dozens of his patients burned up with fever.

  Desperate for a way to reduce his patients’ fevers, Gorrie tried suspending blocks of ice from the hospital ceiling. It turned out to be an effective solution: the ice blocks cooled the air; the air cooled the patients. With fevers reduced, some of his patients survived their illnesses. But Gorrie’s clever hack, designed to combat the dangerous effects of subtropical climates, was ultimately undermined by another by-product of the environment. The tropical humidity that made Florida such a hospitable climate for mosquitoes also helped breed another threat: hurricanes. A string of shipwrecks delayed ice shipments from Tudor’s New England, which left Gorrie without his usual supply.

  Dr. John Gorrie

  And so the young doctor began mulling over a more radical solution for his hospital: making his own ice. Luckily for Gorrie, it happened to be the perfect time to have this idea. For thousands of years, the idea of making artificial cold had been almost unthinkable to human civilization. We invented agriculture and cities and aqueducts and the printing press, but cold was outside the boundaries of possibility for all those years. And yet somehow artificial cold became imaginable in the middle of the nineteenth
century. To use the wonderful phrase of the complexity theorist Stuart Kauffman, cold became part of the “adjacent possible” of that period.

  How do we explain this breakthrough? It’s not just a matter of a solitary genius coming up with a brilliant invention because he or she is smarter than everyone else. And that’s because ideas are fundamentally networks of other ideas. We take the tools and metaphors and concepts and scientific understanding of our time, and we remix them into something new. But if you don’t have the right building blocks, you can’t make the breakthrough, however brilliant you might be. The smartest mind in the world couldn’t invent a refrigerator in the middle of the seventeenth century. It simply wasn’t part of the adjacent possible at that moment. But by 1850, the pieces had come together.

  The first thing that had to happen seems almost comical to us today: we had to discover that air was actually made of something, that it wasn’t just empty space between objects. In the 1600s, amateur scientists discovered a bizarre phenomenon: the vacuum, air that seemed actually to be composed of nothing and that behaved differently from normal air. Flames would be extinguished in a vacuum; a vacuum seal was so strong that two teams of horses could not pull it apart. In 1659, the English scientist Robert Boyle had placed a bird in a jar and sucked out the air with a vacuum pump. The bird died, as Boyle suspected it might, but curiously enough, it also froze. If a vacuum was so different from normal air that it could extinguish life, that meant there must be some invisible substance that normal air was made of. And it suggested that changing the volume or pressure of gases could change their temperature. Our knowledge expanded in the eighteenth century, as the steam engine forced engineers to figure out exactly how heat and energy are converted, inventing a whole science of thermodynamics. Tools for measuring heat and weight with increased precision were developed, along with standardized scales such as Celsius and Fahrenheit, and as is so often the case in the history of science and innovation, when you have a leap forward in the accuracy of measuring something, new possibilities emerge.