9 The Fuel of War

9

THE FUEL OF WAR

Amateurs talk tactics, but professionals talk logistics.

—ANONYMOUS

The fate of Europe and all further calculations depend upon the question of food. If only I have bread, it will be child’s play to beat the Russians.

—NAPOLEON BONAPARTE

“More Savage Than the Sword”

What is the most devastating and effective weapon in the history of warfare? It is not the sword, the machine gun, the tank, or the atom bomb. Another weapon has killed far more people and determined the outcomes of numerous conflicts. It is something so obvious that it is easy to overlook: food, or more precisely, control of the food supply. Food’s power as a weapon has been acknowledged since ancient times. “Starvation destroys an army more often than does battle, and hunger is more savage than the sword,” noted Vegetius, a Roman military writer who lived in the fourth century He quoted a military maxim that “whoever does not provide for food and other necessities, is conquered without fighting.”

   For most of human history, food was literally the fuel of war. In the era before firearms, when armies consisted of soldiers carrying swords, spears, and shields, food sustained them on the march and gave them the energy to wield their weapons in battle. Food, including fodder for animals, was in effect both ammunition and fuel. Maintaining the supply of food was therefore critical to military success; a lack of food, or its denial by the enemy, would lead swiftly to defeat. Before the advent of mechanized transport, keeping an army supplied with food and fodder often imposed significant constraints on where and when it could fight, and on how fast it could move. Although other aspects of warfare changed dramatically from ancient times to the Napoleonic era, the constraints imposed by food persisted. Soldiers could only carry a few days’ worth of supplies on their backs; using pack animals or carts allowed an army to carry more supplies and equipment, but fodder for the animals was then needed, and the army’s speed and mobility suffered.

   This was recognized in the fourth century by Philip II of Macedonia, who introduced a number of reforms that were extended by his son, Alexander, to create the fastest, lightest, and most agile force of its day. Families, servants, and other followers, who sometimes equalled the soldiers in number, were restricted to an absolute minimum, allowing the army to throw off its immense tail of slow-moving people and carts. Soldiers were also required to carry much of their own equipment and supplies, with pack animals rather than carts carrying the rest. With fewer animals there was less need to find fodder, and the army became more mobile, particularly over difficult terrain. All this gave Alexander’s army a clear advantage, allowing him to launch lightning strikes that struck fear into his enemies, according to Greek historians. Satibarzanes, a Persian governor, “learning of Alexander’s proximity and astounded at the swiftness of his approach, fled with a few Arian horsemen.” The Uxians, a Persian hill tribe, were “astounded by Alexander’s swiftness, and fled without so much as coming to close quarters.” And Bessus, a treacherous Persian nobleman, was “greatly terrified by Alexander’s speed.” Alexander’s mastery of the mechanics of supplying his army—a field known today as logistics—enabled him to mount one of the longest and most successful military campaigns in history, conquering a swath of territory from Greece to the Himalayas.

   Armies in history rarely brought along all of their own food supplies, however, and Alexander’s was no exception. Food and fodder were also drawn from the surrounding country as the soldiers marched through. Such foraging could be an efficient way to feed an army, but it had the disadvantage that if the soldiers stopped moving, the local area would be rapidly depleted. Initially the army would have plenty of food at its disposal, but on each successive day foraging parties would have to travel farther to reach areas that had not yet been stripped of food. Alexander’s rule of thumb, which was still valid centuries later, was that an army could only forage within a four-day radius of its camp, because a pack animal devours its own load within eight days. An animal that travels four days through barren country to gather food must carry four days’ worth of food for its outward journey; it can then load up with eight days’ worth of food, but will consume half of this on the return journey, leaving four days’ worth—in other words, the amount it started off with. The length of time an army could stay in one place therefore depended on the richness of the surrounding country, which in turn depended on the population density (more people would generally have more food that could be appropriated) and the time of year (there would be plenty of food available just after the harvest, and very little available just before it). Alexander and other generals had to take these factors into account when choosing the routes of marches and the timing of campaigns.

   Delivering supplies in bulk to an army on campaign was best done by ship, which was the only way to move large quantities of food quickly in the ancient world. Pack animals or carts could then carry supplies the last few miles from the port to the army’s inland bases when necessary. This compelled armies to operate relatively close to rivers and coasts. As Alexander conquered the lands around the Mediterranean he was able to rely on his fleet to deliver supplies, provided his soldiers secured the ports along the coast beforehand. Moving from port to port, the soldiers carried a few days’ worth of supplies and supplemented them by living off the land when possible. In the centuries after Alexander’s death, the Romans took his logistic prowess a stage further. They established a network of roads and supply depots throughout their territory to ensure that supplies could be moved quickly and in quantity when needed. Their depots were resupplied by ship, which made it difficult for Roman armies to operate more than seventy-five miles from a coast or a large river. This helps to explain why Rome conquered the lands around the Mediterranean, and why the northern boundaries of its territory were defined by rivers. Maintaining permanent supply depots meant that a large force could move quickly through Roman territory without having to worry about finding food or fodder. The Roman army also introduced rules to govern the process of foraging while on campaign.

   In enemy territory, demanding food requisitions from the surrounding area served two purposes: It fed the invading army and impoverished the local community. Food in such situations was literally a weapon: A marauding army could strip a region bare and cause immense hardship. As a medieval Chinese military handbook puts it, “If you occupy your enemies’ storehouses and granaries and seize his accumulated resources in order to provision your army continuously, you will be victorious.” Sometimes merely the threat of seizure was enough. In Alexander’s case, local officials often surrendered to him before he entered their territory and agreed to provide food for his army, in return for more lenient treatment. As Alexander advanced into the Persian Empire, this was a deal that local governors were increasingly happy to agree to.

   Conversely, removing or destroying all food and fodder in the path of an advancing army (a so-called scorched-earth policy) provided a way to use food defensively. An early example came during the Second Punic War between Rome and Carthage, during which Hannibal, the Carthaginian general, humiliated the Romans by rampaging around Italy with his army for several years. In an effort to stop him, a proclamation was issued that “all the population settled in the districts through which Hannibal was likely to march should abandon their farms, after first burning their houses and destroying their produce, so that he might not have any supplies to fall back upon.” This ploy failed, but on other occasions in history it was highly effective. Another defensive strategy was to deny the enemy access to food-processing equipment. In order to delay the advance of Spanish troops in 1636, French generals were instructed to “send out before them seven or eight companies of cavalry in a number of places, with workers to break all the ovens and mills in an area stretching from their own fronts to as close as possible to the enemy.” Without ovens and mills, seized grain could not be turned into bread, and soldiers would have to make camp for a couple of days to set up portable ovens.

   All these food-related constraints on the waging of war persisted throughout most of human history, despite the emergence of new technologies such as firearms. But over time the supply systems used by armies invariably became more elaborate. In particular, warfare in eighteenth-century Europe became increasingly formalized, and armies came to rely less on requisitions and foraging, which they regarded as old-fashioned and uncivilized, and more on supplies amassed in depots and delivered by wagon trains. Professional soldiers expected to be fed and paid while on campaign; they did not expect to have to forage for food. The resulting need to build up supplies beforehand meant that campaigns had to be planned long in advance. With armies tethered to their supply depots, lightning strikes or long marches were out of the question. One historian has likened wars of this period to “the jousting of turtles.”

   The American Revolutionary War of 1775–1783 provides a microcosm of how logistical considerations could still be crucial in determining the outcome of a conflict, centuries after Alexander and Hannibal. In theory, the British should easily have been able to put down the rebellion among their American colonists. Britain was the greatest military and naval power of its day, presiding over a vast empire. In practice, however, supplying an army of tens of thousands of men operating some three thousand miles away posed enormous difficulties. Britain’s 35,000 soldiers required 37 tons of food a day among them (a pound of beef each, plus some peas, bread, and rum); their 4,000 horses needed a further 57 tons.

   To start with, the British commanders expected their soldiers’ reliance on supplies delivered across the Atlantic by ship to be temporary. They hoped that American loyalists would rally to their cause, allowing the army to draw food and fodder from the country in loyalist areas. But this proved to be impractical, both because of the quantities required and because requisitioning food alienated the loyalists on whose support the British strategy depended. Many of the British troops, accustomed to Europe’s more formal style of warfare, lacked experience in foraging and felt that it was beneath them. The British troops found themselves penned up near ports for security, dependent on supplies brought in by sea and unable to move very far inland. Attempts to enlarge the area under control provided a larger area in which to forage, but it caused resentment among the colonists, who refused to continue food production or mounted guerrilla resistance. Foraging expeditions sent beyond the British lines required covering forces of hundreds of troops. A small group of rebels could harass a much larger foraging party, picking off men using ambushes and snipers. The British lost as many men in such skirmishes as they did in larger pitched battles.

   Unwilling to venture inland, where their movements would end up being determined by the needs of supply rather than military strategy, the British concluded that they would need to build up a reserve of at least six months’ worth of food (and ideally a year’s worth) before mounting a major offensive, a condition that was met only twice over the course of the eight-year war. The shortage of supplies also meant that the British were unable to press their advantage when the opportunity arose, repeatedly giving their opponents the chance to regroup. The British failed to strike a decisive blow in the early years of the conflict, and after other European powers entered the war on America’s side it became clear that Britain could not win.

   The American forces also suffered from supply problems of their own, but they had the advantage of being on familiar territory, and could draw manpower and supplies from the country in a way the British could not. As George Washington, the commander in chief of the American forces, remarked shortly afterward, “It will not be believed that such a force as Great Britain has employed for eight years in this Country could be baffled in their plan . . . by numbers infinitely less, composed of men sometimes half starved; always in rags, without pay, and experiencing, at times, every species of distress which human nature is capable of undergoing.” The British failure to provide adequate food supplies to its troops was not the only cause of its defeat, and of America’s subsequent independence. But it was a very significant one. Logistical considerations alone do not determine the outcome of military conflicts, but unless an army is properly fed, it cannot get to the battlefield in the first place. Adequate food is a necessary, though not sufficient, condition for victory. As the Duke of Wellington put it: “To gain your [objectives] you must feed.”

“An Army Marches on Its Stomach”

In the early hours of October 5, 1795, a promising young artillery officer named Napoleon Bonaparte was put in charge of the forces defending the French government, known as the National Convention. It had been elected in 1792, in the wake of the French Revolution that had overthrown the monarchy, but there were still large numbers of royalist sympathizers in the country. An army of thirty thousand royalists was now advancing on the Tuileries Palace in Paris, where the convention’s members had taken refuge. Napoleon immediately sent a cavalry officer to fetch forty cannons and their crews, and by dawn he had positioned them carefully in the streets around the palace and had them loaded with grapeshot. His defending forces were outnumbered six to one, and at one point Napoleon had his horse shot out from under him as he directed his men. When the royalist columns launched their main attack, the defending troops managed to channel them toward the main bank of guns, positioned in front of a church. Napoleon gave the order to fire, and the cannons cut down the royalist troops with devastating effectiveness, causing the survivors to turn and flee. “As usual I did not receive a scratch. I could not be happier,” Napoleon wrote to his brother Joseph afterward. It was to prove a turning point in his career.

   A few days later General Paul Barras, who had delegated the defense of the government to Napoleon, appeared with him and other officers before the convention’s members, who wanted to express their thanks. Without warning one of the politicians climbed up to the dais to speak, and instead of thanking Barras, he declared that the hero of the hour had in fact been “General Bonaparte, who had only that morning in which to station his cannon so cleverly.” Napoleon instantly became a celebrity, applauded whenever he appeared in public, and he was rewarded soon afterward with the command of the French forces in Italy. In the months that followed he waged a rapid and brutal campaign against the Austrians, bringing most of northern Italy under French control. Napoleon even dictated the terms of the peace with the Austrians, despite lacking the formal authority to do so. He became a national hero in France and used his success on the battlefield to win political influence in Paris, paving the way for his seizure of power in 1799. After his Italian campaign one French general even described him as “a new Alexander the Great.”

   This was in fact quite an accurate description, because one of the main things that distinguished Napoleon from other generals of his day, and shaped the course of his career, was the readoption of Alexander’s minimalist approach to logistics. As a French general, the Comte de Guibert, had pointed out in the 1770s, armies of the period had become terribly reliant on their cumbersome supply systems and depots, or magazines. He suggested that they ought to be more mobile, travel light, and live off the country. Guibert also observed that relying on standing armies of professional soldiers meant that most ordinary people were untrained in the use of arms. He predicted that the first European nation to develop a “vigorous citizen soldiery” would triumph over the others. In the event his ideas prevailed, but not because of a deliberate program of military reform. Instead the French Revolution in 1789 resulted in the collapse of the old supply system and forced French soldiers fighting in the wars that followed to fend for themselves.

   Reliance on living off the land began as a necessity, but the French army soon developed it into an organized system of requisitioning and amassing food, fodder, and other supplies. As Napoleon himself explained to one of his generals: “It is up to the commanding generals to obtain their provender from the territories through which they pass.” Individual companies would send out eight or ten men under the command of a corporal or sergeant, for as little as a day or as a long as a week. These foraging parties would spread out behind the vanguard of the advancing army and requisition food from nearby villages and farms, sometimes paying for it with gold, but more often with an assignat, or receipt, that could in theory be presented for reimbursement once hostilities had ended. (The expression “as worthless as an assignat” indicates how rarely this happened in practice.) The foragers would then return to their companies to distribute what they had collected, with the food often being made into a stew or soup. This resulted in much less waste than the disorganized pillaging of the past, and French soldiers quickly became experts at finding hidden stores and evaluating how much food was available in a given area. “The inhabitants had buried everything underground in the forests and in their houses,” observed one French soldier of the time. “After much searching we discovered their hiding places. By sounding with the butt ends of our guns we found provisions of all sorts.”

   All this made French armies extremely agile; they needed around one eighth of the number of wagons used by other armies of the time, and were capable of marching fifty miles per day, at least for a day or two. Greater mobility dovetailed neatly with Napoleon’s military strategy, encapsulated in the maxim “divide for foraging, concentrate for fighting.” His preferred approach was to split up his forces, spreading them out over a wide front to ensure each fast-moving corps had its own area in which to forage, and then suddenly concentrating his troops to force the enemy into a decisive battle. The result was a stunning series of French victories that gave the French army under Napoleon a fearsome reputation.

   Napoleon did not do away with traditional supply systems altogether, however. When preparing for a campaign he would have large depots prepared within friendly territory, to provide supplies for his troops as they crossed the border. Soldiers carried a few days’ worth of supplies, usually in the form of bread or biscuits, for use when foraging could not provide enough food, or when the enemy was nearby and the French forces were concentrated. As Napoleon himself observed, “the method of feeding on the march becomes impracticable when many troops are concentrated.”

   The best example of how all this worked came in the autumn of 1805, in the campaign that culminated in the battle of Austerlitz. Having amassed a large army in northern France with the intention of invading Britain, Napoleon instead found himself threatened by Britain’s allies, Austria and Russia, and ordered his troops to head east through France. Mayors of towns along the way, two or three days apart, were asked to provide provisions for distribution to the soldiers as they passed through. Meanwhile, Napoleon ordered 500,000 biscuit rations to be prepared in cities along the Rhine. A month after being mobilized, Napoleon’s 200,000 troops crossed the Rhine, spread over a front more than one hundred miles across. Each corps was instructed to live off the country to its left, requisitioning supplies from the local people and issuing receipts in the standard French way. Records show just how much food the French were able to extract, even from small towns. The German city of Heilbronn, with a population of around 15,000, produced 85,000 bread rations, 11 tons of salt, 3,600 bushels of hay, 6,000 sacks of oats, 5,000 pints of wine, 800 bushels of straw, and 100 wagons to carry what was not immediately consumed. The city of Hall, with only 8,000 inhabitants, produced 60,000 bread rations, 70 oxen, 4,000 pints of wine and 100,000 bundles of hay and straw. It helped that the French campaign occurred at harvest time, which meant more supplies were available than at any other time of year. Preparing and delivering supplies for such a large army using depots and wagon trains alone, in the eighteenth-century style, would have taken months to organize and would have prevented the army from moving so quickly.

   Napoleon’s aim was to defeat the Austrian army in the Danube region before the Russians arrived to reinforce it. He accomplished this with the celebrated “Ulm maneuver”: Cavalry attacking from the west distracted the Austrian army while the main French force swiftly marched around it, encircling the Austrians and forcing them to surrender. Having taken care of the Austrians, Napoleon then set off in pursuit of the Russian army. This meant traveling through wooded country where there was little food to be had, so Napoleon issued his men with eight days’ rations in bread and biscuits, gathered from the region around Ulm. This sustained his army until it reached richer territory to the east, where it could once again make requisitions; several Austrian depots were also captured. Once Vienna, the Austrian capital, had been taken it could be used as a supply depot, providing vast amounts of food and fodder: 33 tons of bread, 11 tons of meat, 90 tons of oats, 125 tons of hay, and 375 buckets of wine were requisitioned on one day alone. The army was given three days to recuperate before heading north in pursuit of the Russians, now joined by the remaining Austrian forces. The two armies eventually took up positions facing each other near the city of Austerlitz (modern Slavkov, in the Czech Republic), and Napoleon’s subsequent victory is widely regarded as the greatest of his career. Napoleon had advanced deep inside enemy territory and had prevailed, humiliating the Austrian Empire. His army’s unrivaled speed and mobility, made possible by its ability to break free when necessary from traditional supply systems, played a decisive role in his triumph. As Napoleon himself is said to have observed, “An army marches on its stomach.”

   Having underpinned his greatest victory, however, food also contributed to Napoleon’s greatest blunder: his invasion of Russia in 1812. As he began planning the campaign in 1811, it is clear that Napoleon did not expect his troops to be able to live off the land once they crossed into Russia. He ordered large supply depots to be established in Prussia and expanded the French military train with the addition of thousands of new wagons. And he proposed switching from four-horse to six-horse wagons, with 50 percent greater capacity, to reduce the number of wagons needed to carry a given amount of food. By March 1812 enough supplies had been gathered in the city of Danzig to supply four hundred thousand men and fifty thousand horses for seven weeks, and more supplies were being gathered along the Polish border. Napoleon hoped to mount a swift, decisive campaign, engaging the Russian army near the border and defeating it swiftly. He did not expect his army to have to venture very far into Russia, or to have to depend on foraging for food.

   Napoleon’s army of 450,000 crossed into Russian territory in late June 1812, carrying twenty-four days’ worth of supplies: The men carried four days of rations in their packs, and the rest was in wagons. The problems began almost immediately. Heavy rain turned the poor local roads, little more than dirt tracks, into muddy swamps. The heavy wagons quickly became bogged down, horses broke their legs, and men lost their boots. The infantry moved more quickly, some units advancing seventy miles in two days, but they were then cut off from their supplies. Once the soldiers had consumed the rations they were carrying with them, they had to resort to living off the land. But the countryside was poor, and the army included many inexperienced recruits who were unfamiliar with the efficient French system of foraging. Discipline broke down and instead of careful distribution of supplies there was indiscriminate plunder. The few villages and farms along the route were soon exhausted of food, there was not enough grass to provide fodder for the French horses, and the crops in the fields were not ripe enough to harvest. “The advance guard lived quite well, but the rest of the army was dying of hunger,” a French general later recalled.

   The Russians retreated as the French advanced, abandoning their positions and falling back toward Moscow. Napoleon expected the richer country around Smolensk and Moscow to be able to provide food for his army, so he pressed on. But the Russians were stripping the countryside and destroying supplies as they retreated. The French army began to disintegrate as the men, weakened by hunger, fell prey to disease. A Russian general observed: “The roads were strewn with the carcasses of horses, and swarming with sick and stragglers. All French prisoners were carefully questioned as to the matter of subsistence; it was ascertained that already, in the neighborhood of Vitebsk, the horses were obtaining only green forage, and the men, instead of bread, only flour, which they were obliged to cook into soup.” By the end of July, a mere five weeks after the start of the campaign, the French army had lost 130,000 men and 80,000 horses, and had yet to bring the enemy to battle. In August an indecisive battle was fought at Smolensk, which fell to the French, but only after the Russians had destroyed all supplies of food in the city. A far bloodier battle at Borodino ended with a Russian retreat, leaving the road open to the capital.

   By denying Napoleon a decisive victory Prince Mikhail Illarionovich Kutuzov, the Russian commander, forced him to move even deeper into Russia, worsening his supply problems which, the Russians knew, posed the greatest threat to Napoleon’s soldiers. Upon his arrival in Moscow with one hundred thousand remaining troops, Napoleon expected to be met by the city elders, but instead he found the city abandoned, with no civil administration to organize the collection of supplies for the army. Fires were already burning when the French arrived, and they turned into a huge conflagration, destroying three quarters of the city and many of its stores of food. (As well as setting fires, the retreating inhabitants of Moscow had also destroyed all the fire-fighting equipment.) The capture of the Russian capital proved to be a worthless victory: Napoleon had expected the Russians to capitulate and sue for peace, but he soon realized that they had no intention of doing so. The longer the French remained in the city, the more vulnerable they would become. A month after its arrival, the army began its retreat westward, accompanied by thousands of wagons loaded with loot. But treasure cannot be eaten, and the shortage of food prompted infighting and further desertions.

Napoleon’s retreat from Moscow.

   Discipline collapsed and the army dissolved into a disorderly, ragtag horde thinking only of its own survival, weakened by hunger and illness and reduced to eating dogs and horses. Stragglers were set upon by Cossacks and tortured to death by local peasants. Abandoned wagons and cannons littered the roads. “If I met anyone in the woods with a loaf of bread I would force him to give me half—no, I would kill him and take it all,” wrote one French soldier. The winter set in later than usual, in early November, toppling horses on icy roads and freezing men to death as they camped out at night. It is sometimes claimed that the Russian winter was responsible for Napoleon’s defeat, but it merely hastened the destruction of his army, a process that was already well advanced. Only around 25,000 of Napoleon’s main force of 450,000 troops eventually withdrew from Russia in December 1812. Napoleon had been defeated, and the myth of his invincibility had been shattered. His command of logistics had helped to make him the ruler of most of Europe, but it failed him in Russia and marked the beginning of his decline.

The Invention of Canned Food

In 1795, in an effort to improve the diets of soldiers and sailors during military campaigns, the French government offered a prize to anyone who could develop a new way to preserve food. The rules stipulated that the resulting food should be cheap to produce, easy to transport, and better tasting and more nutritious than food preserved using existing techniques. Salting, drying, and smoking had all been used to preserve foodstuffs for centuries, but all of them affected the taste of food and failed to preserve many of its nutrients. Experiments to find better ways to preserve food had been going on since the seventeenth century, when scientists had begun to take an interest in the process of decomposition and, by extension, how it could be prevented.

   Robert Boyle, an Irish scientist known as the “Father of Chemistry,” developed a vacuum pump and made many discoveries with it, showing for example that the sound of a ringing bell inside a sealed jar diminished in volume as the air was pumped out. Boyle also speculated that the decomposition of food was dependent on the presence of air, and he tried preserving food by storing it in evacuated jars. But he eventually concluded that contact with air was not the sole cause of decomposition. Denis Papin, a French physicist, extended Boyle’s work by sealing food in evacuated bottles and then heating them. This seemed to work much better, though the food still spoiled sometimes. From time to time Papin would present his preserved food to other scientists at meetings of the Royal Society in London. In 1687 they reported that he had preserved “great quantities” of fruit: “He shuts up the Fruits in Glass Vessels exhausted of the Air, and then puts the Vessel thus exhausted in hot Water, and lets it stand there for some while; and that is enough to keep the Fruit from the Fermentation, which would otherwise undoubtedly happen.”

   At the time the mechanism of decomposition was not understood, though many people subscribed to the theory of “spontaneous generation,” an idea going back to the Greeks which held that maggots were somehow generated from decomposing meat, mice from rotting piles of grain, and so on. Despite the experimental work of Boyle, Papin, and others, the problem of food preservation remained unsolved. The various preservation techniques developed during the seventeenth and eighteenth centuries were both expensive and unreliable. Nobody managed to improve upon the traditional military rations of salted meat and dry biscuits, which explains the conditions attached to the French prize in 1795.

   The man who eventually claimed the prize was not a scientist but a cook. Nicolas Appert was born in Châlons-sur-Marne, on the edge of France’s Champagne region, in 1749. His father was a hotelier, and he became an accomplished chef, serving in the kitchens of various noblemen before setting up as a confectioner in Paris in 1781. In this line of work he was necessarily aware of the use of sugar to preserve fruit, and he wondered whether it could be used to preserve other foods. As his interest in food preservation grew he began to experiment with storing food in sealed champagne bottles. In 1795 he moved to the village of Ivry-sur-Seine, where he began to offer preserved foods for sale, and in 1804 he set up a small factory. By this time some of his preserved food had been tested by the French navy, which was impressed by its quality. “The broth in bottles was good, the broth with boiled beef in another bottle very good as well, but a little weak; the beef itself was very edible,” its report concluded. “The beans and green peas, both with and without meat, have all the freshness and flavor of freshly picked vegetables.”

   Appert later described his method as follows. “First, enclose the substances you wish to preserve in bottles or jars; second, close the openings of your vessels with the greatest care, for success depends principally on the seal; third, submit the substances, thus enclosed, to the action of boiling water in a bain-marie . . . fourth, remove the bottles from the bain-marie at the appropriate time.” He listed the times necessary to boil different foods, typically several hours. Appert was not familiar with the earlier work of Boyle, Papin, and others; he had devised his method solely by experiment and had no idea why it worked. It was not until the 1860s that Louis Pasteur, a French chemist, finally determined that decomposition was caused by microbes that could be killed by applying heat. That is why Papin’s technique, which involved heating, had worked; but most of the time he had not heated his food samples enough to kill off the microbes. Appert’s long process of trial and error had revealed that heat had to be applied for several hours in most cases, and that some foods needed to be heated for longer than others. “The application of fire in a manner variously adapted to various substances, after having with the utmost care and as completely as possible, deprived them of all contact with the air, effects a perfect preservation of those same productions, with all their natural qualities,” he concluded.

   Word of Appert’s products spread and they went on sale as luxury items in Paris; his factory was soon employing forty women to prepare food, put it into bottles wrapped in cloth bags in case of breakage, and then boil the bottles in vast cauldrons. Meanwhile military trials continued, and in 1809 Appert was invited to demonstrate his method to a government committee. He prepared several bottles of food as the officials watched, and a month later they returned to taste the contents, which were found to be in excellent condition. Appert was duly awarded the prize of twelve thousand francs on the condition that he publish the details of his method in full, so that it could be widely adopted throughout France. Appert agreed, and his book, The Art of Preserving All Kinds of Animal and Vegetable Substances for Several appeared in 1810. In accepting the government prize, Appert agreed not to patent his method in France.

   Within three months of his book’s publication, however, a businessman in London, Peter Durand, had been granted an English patent for a preservation technique that was essentially identical to Appert’s. Durand sold the patent to an engineer named Bryan Donkin for one thousand pounds, and Donkin set up a company in conjunction with two partners involved in an iron works. Instead of preserving food in bottles, Donkin’s firm used canisters made of tin-coated iron, known today as tin cans. Durand admitted that the technique was “an invention communicated to me by a certain foreigner,” and it has long been assumed that he simply stole Appert’s idea. More recent research has indicated, however, that Durand may in fact have been acting on Appert’s behalf in England, and arranged to patent his invention and sell the rights. Appert even visited London in 1814, probably to collect his share of the proceeds from Durand. By this time the Royal Navy had tested the new canned food, and samples had even been presented to the royal family. But Appert came away from London empty-handed. His English partners appear to have cut him out of the deal; he could hardly expose them, since he had been trying to profit by selling his invention to an enemy nation.

   Appert concentrated instead on refining his process and supplying the French army and navy. He embraced the use of tin cans for military supplies, but he continued to sell food in glass bottles to civilian customers. One French explorer, who took Appert’s canned food on a three-year voyage, declared that the invention had “completely resolved the problem of feeding sailors.” Canned food had obvious military advantages. It allowed large numbers of rations to be prepared and stockpiled in advance, stored for long periods, and transported to combatants without the risk of spoiling. Canning could smooth over seasonal variations in the availability of food, allowing campaigns to continue through the winter. The new technology was adopted very quickly: Some of the soldiers on the battlefield at Waterloo in 1815, the scene of Napoleon’s final defeat, carried canned rations. Canned meat fed English and French troops in the Crimean War, and tinned meat, milk, and vegetables were supplied to Union soldiers in the American Civil War. Soldiers have carried canned rations of various kinds ever since. The early cans had to be opened with a hammer and chisel, or using a bayonet. The first can openers appeared only in the 1860s, when canned food started to become popular among civilians.

   As far as the civilian population was concerned, canned food was still a novelty or luxury item. At the Great Exhibition in London in 1851, the company founded by Bryan Donkin some four decades earlier displayed “canisters of preserved fresh beef, mutton and veal; of fresh milk, cream and custards; of fresh carrots, green peas, turnips, beetroots, stewed mushrooms and other vegetables; of fresh salmon, codfish, oysters, haddock and other fish . . . Preserved hams for use in India, China, etc . . . all preserved by the same process . . . The whole preserved so as to keep in any climate, and for an unlimited length of time.” Expensive preserved foods, including truffles and artichokes, were also exhibited by Appert’s company, now run by his nephew.

   But canned foods did not remain luxuries for much longer. Strong military demand prompted inventors to devise new machinery to automate the process of sealing cans, and it was found that adding calcium chloride to the water in which they were treated raised its boiling point and reduced the boiling time required. As volumes increased and prices fell, canned food became more widely affordable. In America, the production of canned food went from five million cans a year to thirty million between 1860 and 1870; in Britain, an outbreak of cattle disease in the 1860s prompted people to turn to canned meat from Australia and South America. Appert died in 1841 at the age of ninety-one, but his method of preserving food, heat-treated in a sealed container, and inspired by the supply difficulties of the French Revolutionary army, is still in use today.

“Forage Liberally”

Canned food was one of two inventions that transformed military logistics during the nineteenth century. The second was mechanized transport, in the form of the railway and the steam locomotive, which could move troops, food, and ammunition from one place to another at unprecedented speed. This meant an army could be resupplied easily—provided it did not stray far from a railway line. The impact of this new development became apparent during the American Civil War, a transitional conflict in which old and new approaches to logistics appeared side by side.

   When the war began in 1861 there were thirty thousand miles of railway track in America, more than in the rest of the world combined. More than two thirds of this track was in the more industrialized northern states of the Union, giving the North a clear advantage in supplying its troops. The Union’s strategy was to blockade the breakaway southern states of the Confederacy in an effort to cause food shortages and economic collapse. A blockade of southern ports was imposed in 1861, and the Union then set about seizing control of the Mississippi River and disrupting the southern rail networks, in order to hinder the distribution of food and supplies. Between 1861 and 1863 the prices of some basic foodstuffs increased sevenfold, causing riots in several southern cities in which angry mobs attacked grocery stores and warehouses. With many basic foodstuffs unavailable, various ingenious substitutes were devised, and both soldiers and civilians resorted to eating anything they could lay their hands on. One Confederate soldier wrote to his wife in 1862: “We have lived some days on raw, baked and roasted apples, sometimes on green corn and sometimes nothing.”

   By the time Ulysses S. Grant was put in charge of all Union forces in 1864, the Confederacy had suffered several significant defeats and the blockade was causing severe food shortages. Grant devised a two-pronged plan to end the war: a large Union force would take on the main Confederate army commanded by Robert E. Lee, and smaller Union forces would meanwhile undermine morale in the South by attacking agricultural regions and cutting railway links to further aggravate the shortages. Accordingly, Union forces attacked the agriculturally rich Shenandoah Valley, an important source of supplies to the Confederate forces, and conducted a scorched-earth campaign, destroying crops, barns, and mills. But it is the campaigns undertaken by William Sherman in Georgia and the Carolinas that highlight how much the field of military logistics had changed—and how much it had not.

   Sherman was under instructions from Grant “to get into the interior of the enemy’s country as far as you can, inflicting all the damage you can against their war resources.” After stockpiling supplies in Nashville, Tennessee, Sherman began the march south toward Atlanta, Georgia, in May 1864, following the line of the railway so that food, fodder, and ammunition could be delivered to his army by train. Special teams of engineers repaired the track as the retreating Confederate army attempted to sabotage it. As he moved south through Georgia, Sherman established new bases in Marietta and Allatoona, supplied by railway from Nashville which lay farther up the the line. In July he informed Grant that “we have been wonderfully supplied in provisions and ammunition; not a day has a regiment been without bread and essentials. Forage has been the hardest, and we have cleaned the country in a breadth of thirty miles of grain and grass. Now the corn is getting a size which makes a good fodder, and the railroad has brought us grain to the extent of four pounds per animal per day.”

   The age-old difficulty of finding enough fodder for animals remained, but when it came to food and ammunition, Sherman’s army was exploiting a state-of-the-art logistics system. Delivering supplies from the rear by rail was a far faster and more reliable alternative to the supply wagons, shuttling between the army and its nearest supply depot, that soldiers had depended on for centuries. Sherman’s men only needed to carry a few days’ worth of supplies to sustain them between rail deliveries. The rail link also meant that ammunition could be delivered in large quantities; Sherman’s army was consuming hundreds of thousands of rounds per day as it fought its way toward Atlanta. Military logistics was starting to shift toward providing supplies for machines, rather than for men and animals.

   Having arrived in the vicinity of Atlanta, Sherman concentrated his efforts on seizing control of the converging railway tracks that connected the city to the rest of the Confederacy. He was prepared to mount a long siege, since he was confident of being able to supply his troops by rail from the north. But as things turned out, he captured the railway lines within a few weeks and the Confederate army abandoned Atlanta. Sherman occupied the city and planned the next stage in his campaign, known as the “March to the Sea.” By contrast with the modernity of his advance on Atlanta, this was to be a rather more old-fashioned stratagem. The plan was to cut loose from the formal supply system and march three hundred miles through Georgia to Savannah, on the Atlantic coast, destroying as much agricultural and economic infrastructure as possible along the way. The army would then head north through the Carolinas to prevent reinforcements reaching Lee’s army, which was besieged at Petersburg, Virginia. Sherman’s troops would carry some rations with them, but they would live off the land as much as possible, destroying what they could not eat. This, one of the last and most effective campaigns of the Civil War, is a striking (some would say infamous) example of the use of food as a weapon. Sherman issued a special field order:

The army will forage liberally on the country during the march. To this end, each brigade commander will organize a good and sufficient foraging party, under the command of one or more discreet officers, who will gather, near the route traveled, corn or forage of any kind, meat of any kind, vegetables, corn-meal, or whatever is needed by the command, aiming at all times to keep in the wagons at least ten days’ provisions for the command and three days’ forage. Soldiers must not enter the dwellings of the inhabitants, or commit any trespass, but during a halt or a camp they may be permitted to gather turnips, potatoes, and other vegetables, and to drive in stock of their camp. To regular foraging parties must be instructed the gathering of provisions and forage at any distance from the road traveled.

   The march began in November, just after the harvest, so the barns were full of grain, fodder, and cotton. Each brigade sent out a foraging party of “bummers” who would set out on foot and return with wagons of food, driving cattle in front of them. Sherman’s troops fanned out and devastated the country, helping themselves to fresh mutton, bacon, turkeys, chickens, cornmeal, and sweet potatoes, among other things. As well as taking the supplies they needed to subsist, the Union soldiers killed pigs, sheep, and poultry and burned and looted many houses, despite their orders to the contrary. They were instructed to destroy mills, barns, and cotton gins only if they encountered any resistance. Sherman recalled in his memoirs that the foraging became general plunder, and was not limited to formal foraging parties as he had ordered: “A soldier passed me with a ham on his musket, a jug of sorghum—molasses—under his arm and a big piece of honey in his hand, from which he was eating and, catching my eye he remarked in a low voice to a comrade, ‘Forage liberally on the country.’ ” Sherman claimed to disapprove of such lawlessness, but it was entirely in keeping with his boast to Grant that he would “make Georgia howl.”

   As well as plundering and destroying farms and mills, the Union solders tore up railway tracks whenever they encountered them and devised elaborate tricks to ensure that they could not be repaired, such as heating and warping the rails and wrapping them around the trunks of trees. This inflicted hardship not just on the people of Georgia, but also on the Confederate armies who relied on their produce, since supplies could no longer be delivered by rail. Sherman’s army also damaged the southern economy by liberating black slaves, thousands of whom followed the army as it marched.

   Sherman’s march spread fear and confusion, not least because his destination was unclear. By the time it became clear that he was heading for Savannah, the Confederate armies were unable to concentrate their forces to stop him. The Union soldiers met little resistance, and attempts by the authorities to organize a scorched-earth defense (“Remove your negroes, horses, cattle, and provisions from Sherman’s army and burn what you cannot carry away”) failed; morale had collapsed, and with it confidence in the government. On his arrival in Savannah, Sherman reported that “we have consumed the corn and fodder in the region of country thirty miles on either side of a line from Atlanta to Savannah as also the sweet potatoes, cattle, hogs, sheep and poultry, and have carried away more than 10,000 horses and mules as well as a countless number of their slaves. I estimate the damage done to the State of Georgia and its military resources at $100,000,000; at least $20,000,000 of which has inured to our advantage and the remainder is simple waste and destruction.”

   More was to come. Sherman then continued his destructive march northward through the Carolinas in the spring of 1865, leaving a trail of destruction forty miles wide. “Sherman’s campaign has produced bad effect on our people,” conceded Jefferson Davis, the president of the Confederacy. Lee reported an “alarming frequency of desertions” from his Confederate army, chiefly due to the “insufficiency of food and non-payment of the troops.” Lee realized his position was untenable and surrendered, and the rest of the Confederate forces soon followed, ending the war.

Food for Machines

The American Civil War encapsulated the shift from the Napoleonic era of warfare to the industrialized warfare of the twentieth century. As Sherman’s men advanced through Georgia, living off the land as armies had done for thousands of years, the opposing armies of Grant and Lee were engaged in trench warfare around Petersburg, their zigzag fortifications prefiguring the elaborate ditches and tunnels that would scar the fields of France during the First World War. The emergence of trench warfare was a consequence of improvements in the range, power, and accuracy of firearms and artillery that were not matched by corresponding improvements in mobility. Armies had unprecedented firepower at their disposal—provided they did not move. For most of history, an army that stayed still risked starvation, unless it could be supplied by sea. But the advent of canned food and railways meant that soldiers could be fed all year round, and for as long as necessary, as they stayed put in their trenches.

   Even so, for most of the First World War the new logistics coexisted with the old. Ammunition and food for the front were delivered by rail; but the only way to carry supplies over the last few miles from the railhead to the front line was by using horse-drawn wagons. Accordingly, enormous quantities of fodder also had to be sent by rail, and an ancient logistical constraint survived into the twentieth century: Fodder was the largest category of cargo unloaded at French ports for the British army during the war. The stalemate of trench warfare ended only with the development of the tank, which coupled greater firepower with mobility and heralded a new era of motorized warfare in which fuel and ammunition, to feed vehicles and weapons, displaced food for men and animals as the most important fuel of war.

   This was vividly illustrated just a few years later during the Second World War, and on the North African front in particular, where the German general Erwin Rommel found himself hemmed in by logistical constraints—primarily that of fuel. The German and Italian troops in North Africa received supplies via the port of Tripoli. Rommel dreamed of defeating the British, based to his east in Egypt, and then choking off the Allies’ supply of oil from the Middle East. But there was no suitable railway line along which he could advance to the east, so his supplies had to be carried across the desert in trucks. As the German troops advanced, convoys of trucks shuttled back and forth between Tripoli and the front, carrying fuel, ammunition, food, and water. Seizing a deep-water port along the coast would reduce the distance that supplies needed to be carried overland, so Rommel captured the Libyan port of Tobruk, near the border with Egypt. But the port’s capacity was limited and approaching ships were sunk by the Allies in large numbers. Rommel’s supply lines were so overextended that 30 to 50 percent of his fuel was being used to ferry fuel and other supplies to the front. The farther east he advanced, the more fuel was wasted in this way. When he retreated or was pushed back westward, his supply problems eased.

   Rommel’s attempt to defeat the Allies in North Africa failed. “The first essential condition for an army to be able to stand the strain of battle is an adequate stock of weapons, petrol, and ammunition,” he eventually concluded. “In fact, the battle is fought and decided by the quartermasters before the shooting begins.” In a previous era he would have mentioned food and fodder. But they were no longer the critical elements of military supply. Food’s central role in military planning had come to an end. But by the middle of the twentieth century food was already taking on a new role: as an ideological weapon.