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Haber (pointing) instructs German soldiers how to deploy shells of chlorine gas.

The Kaiser’s Grim Reaper

By William Walker
Autumn 2017 • MHQ Magazine

Fritz Haber saved millions from starvation. Then he turned his genius to chemical warfare.


“IT WAS A BEAUTIFUL DAY, THE SUN WAS SHINING,” Willi Siebert, a German soldier stationed in the Ypres Sector 1915, recalled in a letter to his son. “Where there was grass, it was blazing green. We should have been going on a picnic, not doing what we were going to do.”

In that area of Belgium near the North Sea, sunny days were rare. A prevailing wind from the west blew frequent sea showers onto the lowlands, where Germans were battling Canadian and French armies for control of the ancient city of Ypres at the northern tip of World War I’s Western Front. The earth was so wet that soldiers from both sides often had to construct trenches by piling sandbags on the parapet of the shallow ditches they had excavated. Even with the extra effort, they often had to stand watch in water that reached their thighs.

On April 22, however, the wind had shifted to the north, and Siebert yearned to bask in the clear, springlike weather it brought. But he knew that he had work to do as his chemical-warfare unit prepared, as part of Operation Disinfection, to open the cocks of 5,730 large pressure tanks containing 168 tons of chlorine gas.

“We sent the infantry back and opened the valves with the strings; everything was stone quiet,” Siebert wrote. “We all wondered what was going to happen. As this great cloud of green-grey gas was forming in front of us, we suddenly heard the French yelling….The hail of bullets going over our heads was unbelievable, but it was not stopping the gas. The wind kept moving the gas towards the French lines. We heard the cows bawling, and the horses screaming.”

A mile south, Canadian soldiers stationed near the French saw puffs of white smoke and then a “queer greenish-­yellow fog that seemed strangely out of place in the bright atmosphere of that clear April day,” one of them, A. T. Hunter, later remembered. “It reached the parapet, paused, gathered itself like a wave and ponderously lapped over into the trenches.”

Instantly, Hunter wrote, “passive curiosity turned into active torment—a burning sensation in the head, red-hot needles in the lungs, the throat seized as by a strangler. Many fell and died on the spot. The others, gasping, stumbling with faces contorted, hands wildly gesticulating, and uttering hoarse cries of pain, fled madly through the villages and farms and through Ypres itself, carrying panic to the remnants of the civilian population and filling the roads with fugitives of both sexes and all ages.”

The panic induced by the first-ever chlorine gas attack was exactly what the German General Staff had hoped for, as the new weapon seemed capable of breaking the stalemate that had developed along the Western Front. The man of the hour was an unlikely hero. Short and squat, with a cigar hanging below his manicured mustache, Fritz Haber was a chemist, not a soldier. He’d made a name for himself by pioneering a scientific breakthrough that benefited the world by dramatically boosting agricultural yields. Now he was helping to launch a breakthrough of a different sort—one promising German victory in the Great War by bringing swift death to Allied soldiers. Congratulations came from the small party of senior officers who had gathered to witness the gas-spewing system Haber had designed; the air resounded with cheers, as the men realized that the enemy had been routed from their trenches.

The effusive Prussian scientist would soon come to be seen as the kaiser’s alchemist—a renowned scientist who could generate victory from a tank of gas, just as he had earlier produced food from thin air. But like many other scientists attracted to the ways of war, Haber would see his weapons destroy much of the world he valued. His was a true Faustian bargain.

Fritz Haber (Ullstein Bild via Getty Images)


BORN IN BRESLAU, PRUSSIA (now Wrocław, Poland), in 1868, Haber was the son of Siegfried Haber, who manufactured dye pigments, paints, and even primitive pharmaceuticals. The boy grew up tinkering in laboratories, and it was no surprise that he excelled in the study of chemistry at the Technical College of Charlottenburg in Berlin and at Friedrich Wilhelm University, also in Berlin, which awarded him a doctorate cum laude in 1891.

After a failed attempt to work with his hardheaded father, the equally stubborn Fritz chose to enter the academic world. Beginning at the University of Jena and continuing at the University of Karlsruhe, Haber experimented with applying high pressure and temperature to chemical processes. During these years, it apparently dawned on him that Germany’s pervasive antisemitism might limit his personal and professional prospects, so he converted from Judaism to Lutheranism. When Haber married Clara Immerwahr in 1901, he insisted that she also forsake her Jewish faith. The first woman to earn a doctorate from Breslau University, Clara had hoped to pursue a career that would allow her to become the scientific equal of her husband, but Haber envisioned a more traditional role for his wife. He made it clear that he expected her to be a hausfrau, bearing and raising children, cooking, and keeping an orderly house.

At Karlsruhe, Haber quickly gained a reputation for brilliance. He brashly proclaimed that he could solve any complex problem, an assertion that seemed to be true. He rocketed through the academic ranks and was soon promoted to full professor.

In the earliest years of the 20th century, Haber undertook experiments that led to his first act of alchemy: producing ammonia from thin air. Combining hydrogen and nitrogen from the atmosphere, Haber’s process produced huge amounts of ammonia fertilizer to boost the yield of almost every crop in the world. In 1911, to capitalize on the commercial potential of his process, Haber joined Carl Bosch of the German industrial giant BASF, and over the next few decades they became wealthy by producing ammonia in Germany and licensing ammonia plants in other countries.

And so it happened that the Jewish chemist from the backwater of the German Empire rose to the apex of its scientific establishment. In 1911, just as the nation was girding for a war that most Germans believed was inevitable, Haber was named to lead the Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry in Berlin. Like his countrymen, Haber was convinced that Germany was encircled by enemies conspiring to restrict its territorial, industrial, and cultural development. Many feared that an attack by France or Russia was imminent. These persistent emotions—rather than the murder of two Austrian royals in the obscure Balkan town of Sarajevo—led Germany to invade Belgium, France, and Russia in August 1914.

Haber’s pioneering work with ammonia had come in the nick of time, and he soon assumed a leading role in the war effort. The demand for explosives for artillery shells was growing exponentially as Germany began to fight a war on two fronts. At the same time, a British naval blockade had cut off Germany’s imports of Chilean sodium nitrate—the active ingredient in explosives and propellants. Haber took on the problem, and soon he had perfected a process to convert ammonia into nitric acid, which could be transformed into compounds like sodium nitrate for explosives.

Experts have estimated that, without Haber’s work, a shortage of explosives would have forced Germany to surrender in 1916—two years before the armistice.


WORLD WAR I USHERED IN THE MARRIAGE of science and weaponry, and Fritz Haber happily presided over the union. “I was one of the mightiest men in Germany,” he later declared in a letter to a fellow scientist. “I was more than a great army commander, more than a captain of industry. I was the founder of industries; my work was essential for the economic and military expansion of Germany.”

As a young man, Haber had served a year of obligatory military service in the Prussian artillery before deciding that such a disciplined environment was too confining for a man of his brilliance. In 1914, however, Haber found life in the service much more amenable. He donned an army uniform, bought a sword, and wore a fancy pickelhaube. Still working primarily at the Kaiser Wilhelm Institute, he became a familiar figure in the royal palace and the halls of government, where he promoted new weapons programs, arranged financing for his latest discoveries, and coordinated production with German industries. Haber’s boast was true: He had become one of the mightiest men in Germany.

One of the new weapons that Haber perfected was poison gas. As Haber repeatedly pointed out to those who questioned the morality of his work, Germany was not the first to employ gas in the Great War. In August 1914 the French had fired shells filled with tear gas (ethyl bromo­acetate) at German invaders. But the winds diluted the gas, and the kaiser’s troops hardly took notice. None of the combatants considered the use of irritants a violation of The Hague Convention of 1899, which forbade the use of poisonous gases in artillery shells.

To keep within the letter—if perhaps not the spirit—of the treaty, Haber set about devising a way to deliver chlorine without artillery shells. His solution was to have German soldiers haul heavy industrial gas tanks across shell-pocked battlefields to the muddy front lines. When winds were favorable, they would open the tanks to direct the gas toward enemy lines through an elaborate system Haber had designed.

Haber claimed that his primary goal was not to kill, but to induce panic in the enemy’s ranks. “Every new weapon is capable of winning a war,” he wrote. “Every war is a war against the soul of the soldier, not the body. New weapons break the morale because they are something new, something he has not experienced, and therefore something that he fears.”

Before the date set for the attack, Haber traveled to Ypres to supervise the installation and implementation of the new weapon system. The first site selected for the cylinders proved unsuitable because of unpredictable winds in the area. As a result, German soldiers were forced to dig up the heavy tanks and manhandle them onto wagons for transport to a new site near the village of Langemarck, northeast of Ypres. Winds at the new site proved more predictable.


BEFORE THE GERMANS COULD LAUNCH THE GAS ATTACK, however, it was nearly spoiled by an unanticipated event. On the morning of April 14, German private August Jäger deserted his unit, crawled through no man’s land, and entered French trenches. To his incredulous captors, Jäger described his company’s installation of 80 gas cylinders, positioned to launch a cloud of poison gas that would asphyxiate Allied troops and breach the door to Ypres.

General Edmond Ferry, the commander of the French 11th Division, took the warning seriously, immediately notified his superiors, and developed plans to forestall the suspected attack. He launched furious artillery barrages in hopes of exploding the gas canisters. But Ferry’s commander believed Jäger’s warning was a ruse, intended to sow confusion. He put off needed adjustments until it was too late.

As the proud inventor of the gas and its projection system, Haber was on hand to witness the carnage. From a rise just south of the Houthulst Forest on April 22, he calculated the direction of the wind and then watched three red rockets fired by German artillery climb into the clear sky—the signal to launch the attack. Immediately, the soldiers Haber had helped to train pulled the lanyards opening the cocks of the buried cylinders, and the ominous gas drifted south across the front.

German soldiers on the front release deadly chlorine gas from cylinders. (Henry Guttmann/Getty Images)

Because few men in the Allied trenches survived the attack, most eyewitness accounts come from soldiers in reserve units south of the front. One was Anthony Hossack of the Queen Victoria Rifles, a unit that had just been relieved from its first action in the assault on German positions at Hill 60. The men were lounging on the grass, celebrating survival, a jubilant event underscored by a congratulatory visit from the commander of the British Expeditionary Force, Sir John French.

As the men relaxed, they were casually observing an artillery bombardment falling on the front lines to their northeast when Hossack spied “a low yellow-grey smoke or vapour, and, underlying everything, a dull confused murmuring. Suddenly down the road…came a galloping team of horses, the riders goading on their mounts in a frenzied way; then another and another, till the road became a seething mass with a pall of dust all over it.”

If the Allies were unprepared for the effects of the chlorine attack, so were the German assault troops, who could hardly believe the sight after crossing no man’s land: “What we saw was total death. Nothing was alive,” wrote Willi Siebert. “All of the animals had come out of their holes to die. Dead rabbits, moles, and rats and mice were everywhere. The smell of the gas was still in the air.”

Worse was the human carnage; Siebert saw the bodies of French and British soldiers everywhere: “You could see where men had clawed at their faces and throats, trying to get breath. Some had shot themselves. The horses, still in the stables, cows, chickens, everything, all were dead. Everything, even the insects were dead.”

Haber had succeeded beyond his wildest dream, but paradoxically his vision of death limited the success of the German drive. Many of the kaiser’s troops were so frightened by what they saw that they were reluctant to advance to exploit the gap. Some feared falling prey to the same chemical agent that had killed their enemies. The delay gave the Allies time to press new troops in to stanch the four-mile gap.

Anthony Hossack’s Vics, as the Queen Victoria Rifles were nicknamed, fought forward with orders to sacrifice themselves to shore up the line. “Whatever happens,” the company’s commander said to his men, “fight like hell.”

They advanced to meet a German attack heading down a road leading directly to Ypres, when another officer made clear exactly what was at stake. “This line must be held at all costs,” he shouted. “Or next is the English Channel.”

Reinforced by the thought that they could be pushed into the sea, the British, Canadians, and French held the line, but with massive casualties. The Germans pressed the offensive with more gas attacks in the next few days, and by the time the line was once again stabilized, the Allies had suffered some 15,000 casualties.

As a result of the technical achievement that seemed to portend the defeat of the Allies, the kaiser called Haber to Berlin, promoted him to captain, and decorated his tunic with sparkling medals: an Iron Cross, the Order of Hohenzollern Swords, and the Order of the Crown. Afterward Haber relaxed in Berlin’s clubs—chiefly Deutsche Gesellschaft 1914 (German 1914 Society), which celebrated national unity and feted the city’s elite. Haber’s devotion to the society—and perhaps to its manager, a black-haired Jewish beauty named Charlotte Nathan—enraged his wife Clara, who for months had written friends complaining of her husband’s domineering personality and her restricted life at home. Throughout the early war years, Clara had become increasingly despondent, a mental state exacerbated by her distaste for the Prussian warrior ethos. She was, in fact, a pacifist who believed that science should be used only for peaceful purposes and had vociferously opposed Haber’s work and, especially, his trip to Ypres to oversee the deployment of his new weapon system.

On the evening of May 1, 1915, Clara took her husband’s army pistol, walked into the garden of their elegant home, test-fired one round, and then shot herself in the heart. The pistol blasts awakened the couple’s 12-year-old son, Hermann, who found his mother just before she died.


HABER DEPARTED FOR THE EASTERN FRONT just two days after Clara’s death. From a bunker, he wrote a friend: “For a month I doubted that I could keep going. But now the war, with its dreadful images and constant demands on all my powers, has made me calmer….It really does me good, every few days, to be at the front, where the bullets fly.”

Haber spent most of his time, though, at his Berlin institute, exploring the production of deadlier poisons, developing more-efficient delivery systems, and designing gas masks for German troops. He also helped to develop a cyanide-based pesticide that could exterminate mice in granaries and lice in bunkers. Haber called it Zyklon.

Although chlorine gas had proved its worth at Ypres, it was difficult to deploy, required high concentrations to be effective, and dissipated quickly. The German General Staff demanded more reliably lethal weapons, and Haber promptly delivered them: phosgene gas, a powerful asphyxiant, and mustard gas, which burned the skin and eyes and cauterized the lungs. Haber also perfected the delivery of these new munitions, designing new shells that could be filled with gas and fired by precise German artillery to designated spots on the battlefield.

By 1916 all the warring nations had tossed caution and compunction to the wind. Each new German gas and delivery system was replicated by the Allies, as French poilus, British Tommies, and, eventually, American doughboys joined in firing chemical-filled shells at the enemy. Fairly quickly, though, the combatants developed more-effective gas masks and other countermeasures. Soldiers became familiar with clanging bells and claxon clatter that sent them scrambling to pull on the despised masks. Everyone complained about the masks, but few rejected the only protection that stood between them and a horrible death.

For the remainder of the war, however, gas aroused dread on the front and outrage at home, inspired by eyewitness accounts of its agonies. One of the most moving came from a British officer who described a harrowing visit to gassed soldiers. “When we got to the hospital we had no difficulty in finding out in which ward the men were, as the noise of the poor devils trying to get breath was sufficient to direct us,” he wrote. “There were about twenty of the worst cases in the ward, on mattresses, all more or less in a sitting position, propped up against the walls. Their faces, arms and hands were of a shiny, gray-black color. With their mouths open and leaden-glazed eyes, all were swaying slightly backward and forward, trying to get breath. It was a most appalling sight—all these poor, black faces struggling for life—what with the groaning and the noise of the efforts for breath.”

Eight of the 20 soldiers the officer visited died the following night, and he directly blamed Haber and his fellow chemists who had created the horrific gas: “It is without a doubt the most awful form of scientific torture.”

Meanwhile, the hospital trains that rolled endlessly through Friedrichstrasse Station brought the horrors of chemical warfare back to the city of their invention. Despite these foreboding signs, Berlin’s ruling classes continued to party through 1916 and 1917, confident that the nation’s borders still protected them from war’s violence. Although the British blockade had reduced rations, scarcity and famine had yet to touch Berlin. The city’s military and corporate elite was buoyed by Russia’s departure from the war after the October Revolution of 1917. Living an untroubled life of luxury as a war hero, Haber was still optimistic that Germany could win the war or secure favorable armistice terms. 

British 55th (West Lancashire) Division troops blinded by tear gas wait in line to be treated at a dressing station near Béthune, France, during the Battle of Estaires in 1918. (2nd LT. T.K. Aitken/Imperial War Museums via Getty Images)

Haber renewed his visits to the German 1914 Society, where he sedulously courted Charlotte Nathan, 20 years his junior. Haber persuaded her to follow his conversion from Judaism to Lutheranism, and they were married in Berlin’s Kaiser Wilhelm Memorial Church on October 25, 1917.


AS 1918 DAWNED, THE FAINT OUTLINE OF OMINOUS writing began to appear on the walls of fortress Germany. The Americans had arrived on the continent with massive resources, including armaments and munitions that the blockade-choked Germans could never match. While Haber was a true believer in Germany’s destiny, he was also a pragmatic scientist who relied on empirical evidence. By his calculations, the numbers were adding up against the German war machine.

At a climactic meeting with the kaiser’s chief warlords, Field Marshal Paul von Hindenburg and General Erich Ludendorff, Haber assumed his accustomed professorial mien. “We can only win the war if we are able to build enough submarines to block enemy reinforcements, and enough aircraft to achieve mastery of the air,” he declared. “But we are fighting a poor man’s war. We cannot build enough of both of them—enough submarines and enough aircraft.”

Haber concluded his lecture by advising his military masters to make peace as soon as possible, while the kaiser’s troops still held commanding positions in France and Belgium. But the militarists persisted until November 1918, when the entire imperial structure became so debilitated that it collapsed on itself. The kaiser, his warlords, and the once invincible German army were swept away, along with the acclaim formerly accorded Haber.

Haber seldom looked back, but years later he reflected on Germany’s wartime disaster: “The great technical accomplishments that the past 50 years have granted us, when controlled by primitive egoists, are like fire in the hands of small children.” Naturally Haber excluded himself from the ranks of the egoists. In fact, he proudly kept a framed aerial photograph of the Ypres gas attack on his office wall for years after the war, according to a New York Times reporter who interviewed him at the institute.

Haber’s widespread notoriety from the war did haunt him from time to time. Shortly after the armistice, a rumor reached him that his name was on a list of German war criminals—fugitives that the victorious Allies were seeking to arrest and try. Haber quickly sent his family to Switzerland, and he soon followed to escape the foreign authorities occupying portions of western Germany. After a few weeks, however, Haber returned to the Kaiser Wilhelm Institute. He heard nothing more of the matter.

In November 1919 Haber was awarded the Nobel Prize for Chemistry; two of his fellow countrymen were named laureates in physics. Protests rolled in from scientists of Allied nations. Two Frenchmen declined their prizes, and an American laureate wrote to say that he would never come to a ceremony attended by Haber. For his part, Haber played the news as a gesture welcoming Germany back into the international scientific community and he ascribed the award to his development of the ammonia synthesis process for agriculture.


IN THE DIFFICULT YEARS FOLLOWING THE WAR, Haber set to work on his most ambitious alchemical scheme, designed to help Germany pay 132 billion gold marks in reparations imposed by the Versailles Treaty. It was known that Earth’s oceans are made up of 321 billion cubic miles of seawater, each containing 38 pounds of dissolved gold. Haber reckoned, therefore, that the world’s saltwater offered unimaginable wealth—enough to satisfy the reparations and to make Germany the most powerful nation on the planet.

The key was developing a chemical process to extract the gold, and who better to accomplish this than Nobel Laureate Fritz Haber? He established Department M (for meeresforschung—sea investigation) at the institute, and set his most proficient colleagues to the task. After some false starts, the scientists hit on the right combination of chemicals to precipitate the gold and cleanse its impurities. The end of the process offered a glimpse of the ultimate dream that had enticed centuries of alchemists: a button of pure gold.

Department M then undertook one of the most unusual and secretive scientific expeditions in history. In 1923 Haber and his colleagues, disguising their identities, booked passage on the German ocean liner Hansa and set sail for New York with 932 other passengers, intending to secretly sample seawater. The men knew that some spots in the oceans contained higher concentrations of gold, and they were determined to map them for future exploitation.

Ultimately, however, none of the experiments proved economically feasible, and Germany was forced to pay reparations the hard, slow way. (It made the final payment in 2012.)

Despite strict prohibitions on the production and use of poison gas, Haber and his fellow scientists continued during the mid to late 1920s to work with the German military on a variety of experiments that led to deadlier weapons. Included were Zyklon B, the successor to the Zyklon that Haber had earlier produced, and the discovery of sarin, a powerful nerve gas. Developed by I. G. Farben, which had subsumed BASF, the firm with which Haber had initially worked, sarin was so deadly that 30 of Farben’s employees died while working to perfect production methods for the gas. The firm’s experiments with sarin were conducted in extreme secrecy, some on the vast steppes of Russia, far from the eyes of those enforcing the provisions of the Versailles Treaty, which banned the use of poison gas.

The continuing experiments with deadly weapons reflected a growing wave of anxiety sweeping across Germany in the late 1920s and early 1930s. The stringent peace settlement, galloping inflation, and mounting unemployment fostered anger throughout the defeated nation, and numerous politicians from the right and the left were eager to take advantage of the situation. One was Adolf Hitler. Adding another element to the toxic mix, Hitler focused blame for Germany’s ills on the Jews, claiming that they had stabbed the kaiser’s valiant soldiers in the back in 1918.

Haber seemed unconcerned about the resurgence of anti­semitism, as he had converted to Lutheranism and had rendered excellent service to the Second Reich as a decorated officer. The chemist’s friends—including Albert Einstein, who had immigrated to America—warned him about the “perfidious and unloving” German attitude toward Jews, urging him to leave the nation that once again was drifting toward violence and war. Haber ignored the warnings.

January 30, 1933, was an ominous day for Germany, for Haber, and for the world. German president Paul von Hindenburg, aging and ailing, handed the reins of government to Hitler, and the new chancellor set about installing his own regime. Two months later the government promulgated a law removing all Jewish civil servants, including university professors and scientists, except for those who had served in the Great War.

Although Haber qualified for the exemption, the law finally made clear to him what lay ahead. Under Nazi racial laws, he was a Jew, despite his baptism. He began to visit nearby countries looking for a suitable academic position, but none was available. Casting his net wider, Haber explored the possibility of founding a research institute in Palestine, and his British scientific colleagues eventually persuaded Cambridge University to create an honorary position for him. On October 1, 1933, Haber resigned his position at the Kaiser Wilhelm Institute and moved to England, but he was never comfortable there. A longstanding heart condition began acting up, and Haber’s high-strung psyche plagued him with images of his lost life. On January 27, 1934, sensing that he was near the end of his rope, Haber impulsively left Cambridge and traveled to Basel, Switzerland, a city that had previously provided sanctuary. He was deeply depressed.

“It was not just his health this time, not just nervous exhaustion, but a feeling that he created a life for himself that was false—that he had been living a lie,” Thomas Hager wrote of Haber in a 2009 biography. “He had spent his career fashioning himself into the perfect German. He now understood what that meant—in Hitler’s terms. Despite his conversion, his Nobel Prize, his Iron Cross, his efforts to save the nation, his international stature, his service, his achievements, and his value as a man, the only thing that mattered was that he was a Jew.”

Haber reached Basel on January 28 and checked into a hotel. That evening he succumbed to heart failure, a demise that mercifully spared him the knowledge that many members of his family would be asphyxiated in Auschwitz’s death chambers by the Zyklon B that Haber himself had helped to develop. The move to Switzerland, however, spared his children from that fate.

Alchemist of life-enhancing fertilizer or alchemist of death-dealing gas? Fritz Haber was both. Ammonia-­producing plants bearing the scientist’s name have prevented famines prophesied by generations of population experts. But in addition to millions of Holocaust deaths, Haber’s work made possible the Japanese use of poison gas in China during the Sino-Japanese War as well as the horrible ravages of today’s chemical weapons. Gas-induced deaths in Tokyo subways, the villages of Iran and Iraq, and, most recently, Syrian cities remind the international community that Haber’s genius freed an evil genie from the bottle, and chances are remote that mankind will find a method to coax it back inside. MHQ

WILLIAM WALKER is the author of Betrayal at Little Gibraltar: A German Fortress, a Treacherous American General, and The Battle to End World War I (Scribner, 2016).

This article appears in the Autumn 2017 issue (Vol. 30, No. 1) of MHQ—The Quarterly Journal of Military History with the headline: The Kaiser’s Grim Reaper

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