Absolute Zero and the Conquest of Cold Read online

  Neither did English physicist Edward Nairne, who in 1777 improved on Cullen's work by adding another step to the process. As Cullen did, Nairne used a vacuum to evaporate water through a reduction of pressure, but he then employed sulfuric acid to absorb the evaporated water. The absorption process accelerated the rapid drop in temperature of the water in the surrounding vessel and turned that water into ice more quickly than Cullen's simpler process had done. Still, sulfuric acid was so dangerous to work with, and Nairne's process produced so little ice, that while the experiment was frequently replicated in teaching laboratories over the next fifty years, it was not thought of as having commercial applications. It remained little more than a way to demonstrate the "affinity" between sulfuric acid and water. The production of ice was a theatrical grace note that helped students remember and appreciate the general principle.

  The next man to take an important step in creating artificial refrigeration had even fewer thoughts of commercialization. Martinus van Marum had wanted to be a botanist, but when blocked from an appointment to that professorial chair at Leiden, he had turned to electricity, then to chemistry, which he studied at the elbow of the acknowledged genius of chemistry in that era, Antoine Lavoisier in Paris. As scientists always endeavor to do, in 1787 van Marum sought to test a hallowed tenet from an earlier era, in this instance, whether Robert Boyle's famous law about the inverse-square relationship between the volume of a gas and the pressure on it held under all circumstances. That was indeed the case if the gas was air, van Marum found; but when he used ammonia, recently isolated by Joseph Priestley, the result was different. After 5 atmospheres—about 70 pounds of pressure—had been applied, each additional twist of the compression apparatus did not produce the expected drop in the volume of the ammonia. Even 7 atmospheres did not decrease the volume any further; rather, it forced the gas to become a liquid.

  In liquefying ammonia, van Marum had shown that Boyle's law was not true under all circumstances. He properly concluded that "the aeriform [gaseous] state of whatever fluids ceases to exist, and they are changed into liquids, when they are exposed to the necessary degree of pressure," but he did not test his conclusion's validity by attempting to liquefy gases other than ammonia. Since he was the discoverer of carbon monoxide, he might have tested that, or carbon dioxide, and on the basis of results from three gases replaced Boyle's law with a formula that more adequately described what happens to gases at low temperatures and high pressures.

  Of equal consequence to the story of the exploration of the cold, van Marum also did not choose to closely examine the liquid state of ammonia, though it was significantly cooler than the gaseous state. Had he done so, he would soon have recognized that its marked coolness could readily be used to produce refrigeration and ice. Similarly, when several French chemists improved on van Marum's work, liquefying ammonia by means of less pressure and greater cooling of the gas, they, too, did not go on to test whether other gases could be liquefied or to explore the cold that liquefaction produced.

  The most powerful factor preventing these lines of inquiry from becoming more fruitful and from blossoming into commercial applications was Lavoisier's theory concerning the nature of heat. The "caloric" theory was a direct descendant of the Descartes-inspired notion of ethereal, eel-like particles that had enraged Robert Boyle. A hundred years after Boyle the concept had been so enlarged that it actually claimed to include Boyle's law on gases, as Newton, in his Principia, had suggested that such an elastic-fluid notion could do. In 1787 Lavoisier fully described the elastic fluid he labeled caloric. It was a subtle, weightless, highly elastic fluid believed to flow around or between particles of a gas, holding them in place by means of "repulsive" forces. Caloric was used to explain such disparate processes as the burning of wood in a fire, the heating of water in a metal caldron, the action of the sun's rays, and chemical production of heat. Because of the theory's perceived totality in explaining heat, many scientists—predominantly the French—considered the subject closed and everything that could be known about heat already understood, leaving no reason to further explore it. For the next seventy-five years, researchers encountered considerable difficulty in advancing basic knowledge about heat and cold, until they disproved the caloric theory and substituted other explanations for the source and transmission of heat.

  Among the first to challenge caloric directly was Benjamin Thompson, the Count von Rumford. During his service in Prussia, von Rumford had observed that when the solid metal of a cast cannon barrel was bored by a steel drill, high heat was produced in a way that, he contended, had nothing to do with caloric but everything to do with friction. Von Rumford even kept a kettle boiling atop the barrel as it was being bored. The calorists dismissed his attack, using arguments shaped sixty years earlier to refute the friction argument against the existence of an imponderable fluid consisting of "fire particles."

  However, in his articles von Rumford expressed in plain words what he understood (somewhat imprecisely) about the principles of heat transmission, and around the year 1800 his articles stimulated the commercial thoughts of a Maryland engineer and member of the American Philosophical Society, Thomas Moore. Moore conceived and built what he called a "refrigerator" and used it to carry butter from his farm 20 miles to the Georgetown market of the then-small national capital city of Washington, D.C. The device was rudimentary—a tight cedar tub, stuffed with rabbit fur as insulation around the edges, with ice within that, surrounding in the center an airtight sheet-metal butter container—but it succeeded in preventing the cool air inside the container from dissipating and thus kept his butter cool. Housewives willingly paid high prices at market for Moore's firm butter, spurning his competitors' products, which, though priced lower, were unrefrigerated and melted to the consistency of grease. Moore patented his device, and in 1803 he published a pamphlet, An Essay on the Most Eligible Construction of Ice-Houses; Also, a Description of the Newly Invented Machine Called the Refrigerator. His patent was ineffective, since any carpenter could construct a refrigerator, so Moore made little money from the ice trade. His pamphlet, however, influenced many people, among them the inventor Oliver Evans of Delaware and the commodities trader Frederic Tudor of Massachusetts.

  In the fledgling United States of America, any scientific or technological investigation or innovation had to be intensely practical, else no one would pursue it. Oliver Evans had made machines that improved the milling of wool, and steam engines that worked in factories and aboard a dredge; so in 1805, when Evans adapted the work of Moore, Cullen, and Nairne and designed a refrigeration machine that used ether in place of sulfuric acid, and wrote a short book about it, there might have been a reasonable hope that refrigeration would take hold in the United States. But Evans never bothered building his refrigeration machine, deciding it would not bring him as much wealth as would tinkering with steam engines. In that field, too, he lost out to another, better-funded inventor, even though Evans's design for a steamboat preceded Robert Fulton's and was more efficient than his.*

  While Evans did not seize the moment for taking the initiative in refrigeration, at almost exactly the same time Frederic Tudor did. The growth of the natural-ice business in the United States is a classic tale, and its protagonist, Tudor, is almost a caricature of the iconoclastic, flawed, driven entrepreneur. Frederic was one of four sons of Colonel William Tudor, a lawyer who had clerked for John Adams and served as a judge advocate general during the Revolutionary War, then became a wealthy mainstay of Boston society. The colonel's three other sons attended Harvard, but Frederic considered Harvard to be "a place for loafers, like all colleges," and so at age thirteen, while his parents were abroad, he left the Boston Latin School and began an apprenticeship in a shipping office. At seventeen, he invented a siphon pump for removing water from the holds of vessels and drafted a letter to the Royal Society about it, but never sent it. Short and slight, full of energy, he was an able thinker despite his minimal schooling.

  At twenty-one
, Frederic accompanied an older brother on a trip through the West Indies, and he returned convinced of the possibilities of making money from that area. After working two more years in the shipping office, trading in pimentos, nutmeg, tea, claret, and other commodities, he was ready to try his own large capitalist venture. At a family picnic in July 1805, another brother, William, half-jokingly suggested to Frederic that the ice that formed on the pond of the family farm at Saugus in winter could be harvested and sold in the Caribbean.

  The idea so galvanized Frederic that he bought a leather-bound journal and inscribed on its front a motto that became his credo: "He who gives back at the first repulse and without striking the second blow despairs of success [and] has never been, is not, and never will be a hero in war, love, or business." He dispatched William and a male cousin to Martinique. Both spoke French well—as Frederic did not—and were able to deal with the upper classes to drum up trade for Frederic's later arrival and to prepare a warehouse, based on Moore's designs, to hold the ice. But in March 1806, when Frederic Tudor entered the port of Saint-Pierre on a rented brig carrying 130 tons of ice packed in hay, he found that his advance men had decamped to the Leeward Islands, having made no arrangements for him or his cargo. With the equatorial sun rapidly melting his assets, Tudor first tried to sell ice directly from the boat, distributing handbills to tell purchasers how to preserve and use it. As he wrote to his brother-in-law, the ignorance of people concerning ice was laughable: "One carries it through the street to his house in the sun noon day, puts it in a plate before his door, and then complains that 'il fond' [it melted to the bottom]. Another puts it in a tub of water, a third by way of climax put his in salt!" No one on the island had ever seen or tasted ice cream, and many even had no notion of what an iced drink might feel like; to create sales, Tudor had to first inspire demand. He sought out the proprietor of the island's Tivoli Gardens restaurant and managed to persuade him to sell ice creams Tudor would make. On the first night more than $300 worth was sold, a considerable sum. Tudor wrote home that afterward, the Tivoli Gardens man "became as humble as a mushroom." Still, overall the trip was a failure, resulting in the loss of almost half of his capital investment.

  Tudor returned to Boston with ideas for better ice storage in ships and on land, and the next season he managed to sell, at a good profit, a cargo of ice in Havana. "Whenever I find myself run away with by humanity," he wrote to a younger sister, "I feel incompetent to the common duties of existence. My son shall be a fighter. I will glory in him who shall not be too good. He shall have the common frailties of mankind and as many virtues of the bolder order as shall please heaven to award him." It did not take a mentalist to discern that Tudor was describing himself.

  In 1807, blocked from further trade in the Caribbean region because of President Jefferson's embargo on business with colonies of Great Britain and France, Tudor received news of his father's financial ruin. Along with other prominent Bostonians, Colonel Tudor had invested in an attempt to develop land in South Boston; he lost all he had, and thereafter he lived on the small salary he earned as clerk of the Massachusetts Supreme Court. With a sense of the least promising brother becoming the first, and of fulfilling his destiny, Frederic Tudor took on the burden of restoring the family's fortunes.

  A martinet who liked to dress in a blue frock coat with brass buttons, Tudor was more than an astute investor; he was also a skilled technologist who succeeded in reducing his warehouse outflow loss from 56 pounds of water per hour to a mere 18. But his prowess could not overcome what he called a "villainous train of events" that included bad luck, and being tricked out of profits by partners in the islands, and imprisonment for failing to pay debts. By the close of the War of 1812, he was near the end of his rope, telling his diary,

  I have manfully maintained as long as I possibly could that "success is virtue." I say so still: but my heart tells me that I don't believe it. Have I not been industrious? Have not many of my calculations been good? [My enemies and bad luck] have worried me. They have cured me of superfluous gaiety. They have made my head grey; but they have not driven me to despair.

  "Pursued by sheriffs to the very wharf," as he wrote in his diary, Tudor finally embarked on a successful voyage. He made his first sale, to coffeehouses in Cuba, precisely ten years to the day after the Tivoli Gardens episode, and exulted: "Drink, Spaniards, and be cool, that I, who have suffered so much in the cause, may be able to go home and keep myself warm."

  Over the next decade Tudor steadily expanded his enterprise, to Charleston, Savannah, and New Orleans, as well as to more Caribbean islands, creating demand by offering free ice for a month or a season, during which—he proved time and again—the taste for "Northern delicacies" such as ice cream and iced drinks sprouted. Searching for the best packing material with which to separate ice blocks and to keep them dry during transport, he tried hay, rice, straw, twine, and cotton. He also experimented with refrigerating tropical fruits and carrying various return cargoes to New England, but large-scale success still eluded him. He had to bail his brothers out of jail bondage more than once, and in 1822 he experienced what seems to have been a mental breakdown.

  In 1823, while Tudor was recuperating in Maine, across the Atlantic one of those accidents occurred that, so frequently in the history of science, presaged an important advance—in this instance, one that would have tremendous scientific ramifications for the next hundred years of the exploration of the cold, and that would also result in commercial refrigeration techniques that would eventually sound the death knell for the natural-ice business. Young Michael Faraday, who had worked his way up from laboratory assistant to stalwart experimenter at the Royal Institution in London, was experimenting at the request of his mentor, Humphry Davy, on exerting pressure on gaseous chlorine hydrate in an attempt to fully explore the properties of chlorine, which had only recently been identified.

  Davy did not conduct these experiments himself, among other reasons because they were dangerous. During a single month in 1823, there were three separate explosions in Faraday's lab: one scorched his eyelids, another cut his eyes, the third blew glass into his eyes, which he had to carefully flush out.

  On March 6, 1823, a Dr. Paris, Davy's biographer, came in to watch Faraday experiment, and he chided the young man on having a tube containing "oily matter." Faraday agreed that this seemed like sloppy work, and he tried to saw off the end of a pipette to eliminate the contaminated part. In doing so, he must have made a spark that caused a small explosion. When the smoke cleared, the oil in the tube had vanished. The next day, Faraday figured out what had happened and wrote Paris a note about it: "Dear Sir: The oil you noticed yesterday turns out to be liquid chlorine." He also wrote up the results and in a scientific paper claimed credit for the discovery; this claim incensed Davy, who tried to prevent his protégé from being elected to the Royal Society, a blackball that was, fortunately, overridden by the other members. But the wedge between the two men permitted Faraday thereafter to do more work on liquefaction by himself. Shortly, he tackled ammonia.

  A real chameleon of a gas, a pungent compound of nitrogen and hydrogen, at one moment ammonia could exist in the liquid compound "ammonia water," and at the next—when the ammonia water was heated—ammonia would separate from the water and become a gas; and that gas could also be subjected to pressure and turned into a different liquid, a liquefied gas. In 1823 Faraday examined all of these states, and in the process, he demonstrated that liquefied ammonia could be used to generate cold.

  To understand why, and how, it is necessary to repeat, in print, an ice experiment that many scientists were performing for themselves and their students in laboratories all over Europe in the first quarter of the nineteenth century. Its point was to show how ice cools things—not, as most people believed, by conduction alone, by conveying its own coldness to neighboring materials—but mostly by melting, during which ice absorbs heat from its surroundings. Scientists first mixed a pound of water at the boiling point, 212°F
, with a pound of water at 34°F; the result was 2 pounds of water at 123°F, a midpoint that could be mathematically expected. But then they mixed a pound of water at 212°F with a pound of ice at 32°F and obtained a startlingly different result—2 pounds of water at 51°F. An amount of heat that would have been sufficient to raise 2 pounds of water another 72°F had been absorbed by the change from solid ice to liquid water. Faraday recognized that what made ammonia change rapidly from its liquefied to its gaseous state was a similar absorption of heat from the surroundings—and that this was what lowered temperature and produced cold.

  Faraday noted that "there is great reason to believe that [this technique] may be successfully employed for the preservation of animal and vegetable substances for the purposes of food," but he did nothing personally to advance the commercial possibilities of generating cold by means of ammonia's absorptive capacities. The reasons for this inaction are not described in his notebooks or diaries, but he was known to be a determinedly uncommercial man, a member of a Quaker-like religious sect devoted to giving up worldly things to better elucidate the works of God. During the first flush of the Industrial Revolution, Faraday turned down repeated requests from entrepreneurs to act as a paid consultant to their endeavors in other fields, and surely he would not have considered setting up a refrigeration business or licensing his process to others to do so.