The Cabinet of Dr. Haber

“As far as science is concerned, there is no doubt whatsoever in my mind that to look upon it as a means of increasing one’s power is a sin against the Holy Ghost.”

—Karl Popper, “The Moral Responsibility of the Scientist”

*

FRITZ HABER:

“It was never, ever my intention, to engineer more deaths by my invention.”

CLARA HABER:

“Your process led to death and devastation.”

FRITZ HABER:

“It saved the world that hurtled to starvation.”

These lines from Tony Harrison’s play Square Rounds, which was recently produced in London, epitomize the ambiguous personality and career of Fritz Haber. He was a German chemist, born in 1868, famous for being the first scientist to have synthesized ammonia from the nitrogen in the air; this opened the way to the synthesis of the nitrogen fertilizers that have dramatically increased agricultural production throughout the world. He is also infamous for having introduced poison gas in the First World War.

Haber was larger than life in every sense. Photographs show him taller than everyone else in the picture, stiffly erect and formally dressed with a pince-nez and a starched collar turned down at the corners, lording it over his assembled laboratory staff, a Geheimrat par excellence. After April 1933, when the Nazis had forced him, a Jew by birth, from all official positions, Haber told a friend: “I have been German to a degree which I feel fully only now.” To Chaim Weizmann he described himself as one of the most powerful men in Germany:

I was more than a great leader of armies, more than a captain of industry. I was the founder of great industries. My work opened the way to the great industrial and military expansion of Germany. All doors stood open to me.

As Dietrich Stoltzenberg makes clear in his detailed biography, Haber had been devoted to the glory of Bismarck’s German Reich and the German Emperor with an intensity hard for present generations to comprehend. He continued to visit the Emperor during his exile in Holland after Germany became a republic. He was a man of intellectual brilliance, with wide knowledge, overriding ambition, and a certain lack of humanity. The father, a respected businessman trading in dyes and pharmaceuticals, was more observant of the Prussian virtues of hard work, sense of duty, order, and discipline than of the Jewish rites. He compelled Fritz to enter his flourishing, carefully managed business, but when one of Fritz’s impulsive transactions resulted in a severe loss, he allowed him to launch himself on what was then thought to be a badly paid academic career in chemistry instead. He did not foresee that one day guests invited to Fritz’s Berlin residence would dine off gold plates.

Chemistry had fascinated Haber as a schoolboy. As was customary in Germany, he studied at a succession of universities, and finally landed at the Technical University in Karlsruhe. Knowing that academic careers were closed to non-Christians, he had himself baptized in the Lutheran faith. At the turn of the century, it was hard for anyone without an independent income to follow a university career, because assistant professor (Privatdozent) and associate professor (Ausserordentlicher Professor) were honorary posts rewarded only with the fees paid by the students they were able to attract to their lectures, and only full professors received an adequate salary. His poverty drove Haber to earn money from patents, and books, and to accept assignments from private industry. He worked furiously, determined to get to the top. When he failed to be appointed to a coveted chair in physical chemistry, chemistry’s elder statesman Wilhelm Ostwald counseled him: “Achievements generated at a greater than the customary rate raise instinctive opposition amongst one’s colleagues.”

In 1901 Haber married Clara Immerwahr, a thirty-year-old woman, daughter of another respected Jewish family in Breslau, whom he had known as a teen-ager. As Gerit von Leitner’s biography of Clara shows, she matched him in ambition and determination, having fought against prejudice and opposition to become the first woman Ph.D. in science at Breslau University. She was not pleased when shortly after the birth of their first son, Hermann, Haber left for a three-month tour of America.

In 1908, when he was only forty, Haber was appointed full professor of physical chemistry at Karlsruhe, where a contemporary described him as impulsive, temperamental, and quick-thinking, an excellent lecturer and engaging talker on virtually any subject. But in a letter to a friend quoted by von Leitner, Clara complained about his treatment of her:

What Fritz has gained in these eight years, I have lost, and what is left of me fills me with profound dissatisfaction. I have always felt that it is only worth having lived if one has developed all one’s faculties to the full, and has experienced everything that life can offer. That is what made me decide to get married, since otherwise one chord of my soul would lie fallow.

If my elation was short-lived… that is due mainly to Fritz’s overpowering way in his home and marriage, besides which anyone perishes who doesn’t assert herself more ruthlessly than he…. I ask myself whether superior intelligence makes one person more precious than another and if much of me that has gone to the devil, because it has gone to the wrong man, is not more valuable than the most important electronic theory.

If you want to make your name in science, try to accomplish something that has defeated everyone else. In 1784 the French chemist C.L. Berthelot discovered that ammonia consists of one atom of nitrogen and three atoms of hydrogen. For the next 125 years many chemists tried to make ammonia from these two gases and failed, largely because the laws governing chemical reactions were not fully understood. Haber, an excellent theoretician and talented experimenter, determined to solve the problem, at first without any thought of practical applications. ¹ He and his young English collaborator Robert Le Rossignol made a careful study of the temperatures and pressures required to combine free nitrogen and hydrogen gas so as to produce more than tiny quantities of ammonia.

They found that the formation of ammonia required a pressure on the two gases of more than two hundred times that of the atmosphere at sea level and a temperature of 200å¡C (390å¡F), extreme conditions never reproduced in a laboratory before. Even then the ammonia was made only very slowly. To hasten the reaction, a catalyst was needed, in this case a metal on whose surface hydrogen and nitrogen would combine faster. Haber and Le Rossignol tried one possible metal after another until a powder of the rare metal osmium accelerated the reaction spectacularly. On July 2, 1909, they triumphantly demonstrated an experiment producing about seventy drops of ammonia a minute to the directors of the Badische Anilin und Soda Fabriken, then Germany’s largest chemical firm.

At the time, saltpeter mines in Chile were the main sources of natural nitrogen fertilizer, but their output was limited and expected to be exhausted by about 1940. Some nitrate was also recovered from coal gas, but not nearly enough to satisfy demand. On the other hand, the nitrogen in the air was unlimited, hydrogen was abundant in coal gas, and their compound, ammonia, could be used as a fertilizer either by combining it with sulfuric acid or by oxidizing it so as to produce nitrates.

Convinced by the promise of Haber’s demonstration, the directors of the Badische firm provided two of their ablest chemists, Carl Bosch and Alwin Mittasch, with unlimited time and resources to develop the process for industrial production. Badische Anilin took an option on the entire world stock of osmium (220 pounds), but Mittasch also performed over 10,000 tests of ammonia synthesis on 4,000 other catalysts. He finally selected a mixture of iron, which is abundant and cheap, with small amounts of the oxides of aluminum, calcium, and potassium. On September 9, 1913, the first industrial unit set up by Bosch and Mittasch started to produce between three and five tons of ammonia daily, a thousand times the output of Haber and Le Rossignol’s original laboratory apparatus. Current world production of ammonia for fertilizer is about a hundred thousand times greater; all of it is still made with Mittasch’s original iron catalyst, whose efficiency and durability has never been surpassed.

Haber was rewarded with generous royalties and the Nobel Prize for Chemistry for 1918; Carl Bosch received the prize in 1931 for his development of an entirely new technology for the production of ammonia under high pressure, despite an explosion of the ammonia works at Oppau on the Rhine on September 21, 1921, which killed 561 people and made 7,000 homeless (Stoltzenberg fails to mention that appalling disaster).² Unjustly Mittasch was left out. Having accomplished so much, Haber might have taken life easily, but that was not in his restless nature, and in any case he became embroiled in controversy over his discovery. His patents were immediately challenged by an Austrian chemical firm which had suggested the possibility of synthesizing ammonia from its elements and had financed his first experiments. Other firms, which recognized the patents as a gold mine, also made claims against him. Caught up in these disputes, he no longer did original scientific work, but other opportunities now beckoned.

In 1910, the German Emperor founded the Kaiser Wilhelm Gesellschaft zur Förderung der Wissenschaft, a semi-independent body for the support of research which was to prove of immense benefit to German science and learning. It was supported by Leopold Koppel, a respected Jewish banker, who also offered to pay for an Institute of Physical Chemistry in Berlin under Fritz Haber’s direction. Haber said he would accept if he was also appointed to a chair at Berlin University, made a member of the Prussian Academy of Sciences, and given a salary of 15,000 marks a year (equivalent to about $85,000 today). These exacting demands were duly met and Haber accepted. Along with Max Planck and Walter Nernst, Berlin’s leading physicists, he persuaded Einstein to leave Zürich and move to Berlin, and he attracted many excellent young scientists to his new institute. The Kaiser Wilhelm Gesellschaft also built a second large institute for Germany’s greatest chemist, Emil Fischer, who had received the Nobel Prize in 1902, partly for his work on the structure and synthesis of sugars.

In October 1912, Wilhelm II in person was to open both institutes, Stoltzenberg writes. Two of the members, Otto Hahn and his associate Lise Meitner, later famous for their discovery of atomic fission, suggested to the Emperor’s adjutant that they take him to their darkroom and show him the scintillations which alpha rays from radium produced on a fluorescent screen. The adjutant objected, because Wilhelm would be frightened in the dark.³ (Meanwhile the scientists’ wives had hired a gym teacher to teach them how to curtsy to His Majesty.)

Nitrates form an essential part of explosives. When war broke out in August 1914, the British blockade cut Germany off from Chilean supplies of saltpeter, the traditional source of nitrates. The Germans captured 20,000 tons of saltpeter in Antwerp harbor after their invasion of Belgium, but had it not been for Haber’s synthesis of ammonia, German nitrate supplies would have been exhausted and the Germans would have had to sue for peace. Haber volunteered for the army, in which he had served in his teens, but he was rejected now on account of his age. Instead, he became chief of the chemistry section in the War Department for Raw Materials. In December 1914 he attended a test of artillery shells filled with tear gas, but he found the gas was too widely dispersed to have any effect.

According to his assistant, Fritz Epstein, Haber then suggested that the discharge of chlorine gas from cylinders would be more effective.⁴ Chlorine is a greenish-yellow, blinding gas, heavier than air, which immediately produces violent coughing; it corrodes the eyes, nose, mouth, throat, and lungs, and finally asphyxiates the person who inhales it. If blown by the wind toward the enemy lines, Haber proposed, it would sink into the trenches and drive the soldiers out into the open, where they could easily be killed. The idea appealed to the Chief of the General Staff, Erich von Falkenhayn. However, there was the awkward matter of the Hague Conventions of 1899 and 1907, which Germany had signed and ratified. According to the first convention: “The Contracting Powers agree to abstain from all projectiles whose sole object is the diffusion of asphyxiating or deleterious gases.” The second convention also prohibited all use of poisons and poisoned weapons in war.

Falkenhayn saw a fine distinction between projectiles filled with noxious gases and gases being blown by the wind from cylinders on the ground, which the conventions had not foreseen. He put Haber in charge of a project to make such cylinders and promoted him from a noncommissioned officer in the reserve to the rank of captain. In The Poisoned Cloud, his scholarly book on the history of poison gas, Haber’s son Ludwig writes: “In Haber the [High Command] found a brilliant mind and an extremely energetic organizer, determined, and possibly also unscrupulous.”⁵ Stoltzenberg confirms that Haber was without any doubt the initiator of chemical warfare.

Haber threw himself into the task. He worked himself to exhaustion organizing the manufacture of hundreds of tons of chlorine gas and thousands of gas cylinders; he trained special troops to test them and oversaw their installation in the trenches at the front, regardless of danger to his own person.

He also recruited his own young collaborators and many other chemists for the task. When Otto Hahn objected that what he was doing was contrary to international law, Haber argued that in the autumn of 1914 the French had broken it first by firing rifle shells filled with tear gas; according to Stoltzenberg and Ludwig Haber this was untrue. Stoltzenberg writes: “When one reads the reports of Haber’s activity and behaviour at that time, one gains the impression that he was obsessed by his self-imposed tasks.” His boundless ambition seems to have made him determined to win the war single-handed. He planned to have chlorine gas blown toward the Allied lines on a front of fifteen miles, which would either have killed the enemy soldiers or put them to flight. Massed German infantry were to follow and break through the Allied lines. He advised the High Command to use gas only if it could ensure victory, and he also urged that the German troops should be protected with a primitive kind of gas mask.

When the High Command asked the divisional commanders in charge of different sections of the front to cooperate with such an attack, all but Duke Albrecht of Württemberg refused. His troops were engaged in some of the fiercest fighting on the front at Ypres, twenty miles from the Belgian coast. There, Haber’s special troops dug into the German trenches 5,730 cylinders capable of releasing 150 tons of chlorine gas along a four-mile-long front. It was to be blown toward the enemy when the wind came from the east; but this was known to happen, on average, on only one day out of three, and besides, the wind so near the sea was capricious. Ludwig Haber writes:

Here was Haber himself, an academic in uniform, paunchy, rarely without a cigar, pockets bulging, surrounded by young acolytes who managed to look respectful, busy, and unconventional in dress and bearing.

All the wartime documents refer to him deferentially as “Geheimrat Haber.” He prevailed upon Otto Hahn, who commanded a machine-gun section, to become a participating “observer,” and the future Nobel Laureates in Physics James Franck and Gustav Hertz also joined him. But Max Born, another young physicist at Haber’s Institute and a future Nobel Laureate, refused to take part. The chemist Hugo Stoltzenberg, the father of Haber’s biographer, ran chlorine filling stations near the front. By April 11, 1915, the unwieldy cylinders, each weighing nearly 200 pounds, had been installed at night; but the masks for the German troops never arrived.

In his book dealing with his father’s work on poison gas, Ludwig Haber writes:

The first gas alert order was given on 14 April at 22.30 and cancelled at 01.45 on 15 April. The second was on 19 April at 15.00, but was countermanded. By then the [High Command] had become cautious and owing to the Russian threat on the Austro-Hungarian front became reluctant to commit reserves earmarked for the east to something as uncertain as the follow-up to a gas attack. The third alert was given on 21 April at 17.00, postponed first to 04.00 on 22 April, then to 09.00 and then to the afternoon.

The troops, the Pionierkommando, and the specialists had had very little rest and were on edge. They were sure the Allies had been alerted. They had indeed. Three weeks earlier the French, then still in the south of the Salient, were told by prisoners of the installation of cylinders, and there was visual evidence of gas cylinder explosions in March. But the French ignored these warnings….

The simultaneous opening of almost 6,000 cylinders which released 150 tons of chlorine along 7,000 meters within about ten minutes was spectacular…. Within minutes the Franco-Algerian soldiers in the front and support lines were engulfed and choking. Those who were not suffocating from spasms broke and ran, but the gas followed. The front collapsed.

The Germans advanced cautiously. They too were taken by surprise and followed the cloud, delayed not by resistance, but by patches of gas in low ground and ruins…. German hesitations and darkness saved the French by giving them time to regroup…. The Germans’ elation at their initial success soon turned to disappointment when on 23 April their Divisions, upon being ordered to advance, met with increasingly stiff resistance.

The gas attack caused 15,000 Allied casualties, 5,000 of them fatal; but Haber’s great victory still failed to materialize. He arrived home in Berlin disappointed and exhausted a few days later. On the evening of May 1 the Habers had guests for dinner, and that same night, while Haber was asleep, Clara shot herself with his service pistol, waking up their fourteen-year-old son, who found her in a pool of blood in their garden. Next morning Haber dutifully left for the Eastern front.

Gerit von Leitner, in her biography of Clara, and Tony Harrison, in his play about Haber’s career, attribute her suicide to her disgust with Haber’s activities, which included tests of chlorine and other poison gases on animals at Haber’s Institute, next door to their official residence. Gerit von Leitner writes that Clara was heartbroken when the young chemist Otto Sackur, a friend of hers from student days at Breslau University, was killed in an explosion at the institute. She also describes a row in which Haber blamed Clara’s gossip for the army’s failure to break through.⁶ Stoltzenberg could find no evidence that Clara’s suicide was a protest against Haber’s war work. But according to Kurt Mendelsohn’s book The World of Walter Nernst, Clara had pleaded with Haber repeatedly not to work on chemical warfare;⁷ von Leitner has found a recorded statement by James Franck saying that Haber’s part in the gas war certainly influenced Clara’s suicide, and that Haber blamed himself bitterly for it throughout his life.

Stoltzenberg writes that their marriage was happy at first, but that this changed after their son’s birth, when Clara became increasingly concerned with domestic trivia, which irritated Haber. He also writes that Clara was hospitalized more than once for depression, a crucial point which von Leitner fails to mention. He cites Clara as one of those people “whose search for self-fulfillment makes them build a wall around themselves which becomes their self-imposed prison.” She wrote some farewell letters which have not survived, and von Leitner suspects that Haber destroyed them.

From the front Haber wrote to a friend: “For a month I doubted that I would hold out, but now the war with its gruesome pictures and its continuous demands on all my strength has calmed me.” He continued to devote himself to chemical warfare, and according to Stoltzenberg this satisfied him completely. Once Haber had unleashed chlorine gas, the Allies soon matched the German effort, and the prevailing west wind blew in their favor.

Haber’s actions continued to contradict Montesquieu’s belief that knowledge makes men gentle. Despite his complaints of his overwhelming responsibilities at the front he found time to conceive strategies for research on armaments when the war was over. When some of the German military were making plans to annex all of Belgium and parts of northern France, and for good measure to invade England to teach the English a lesson, Haber got his benefactor Koppel to propose to the war minister that he finance a Kaiser Wilhelm Foundation for War Technology. Haber also induced Carl Duisberg, the head of Bayer, to propose that a Kaiser Wilhelm Institute for Chemical Warfare be established with himself as director. Strangely, Haber made this proposal even though he apparently was convinced as early as 1916 that Germany would lose the war. The Emperor approved the Foundation on December 17, 1916, with Fritz Haber, Emil Fischer, Walter Nernst, and three less famous chemists on the governing board. The Kaiser Wilhelm Gesellschaft hesitated to collaborate with the Foundation at first, and one of its members objected that killing people was not the Gesellschaft’s job. But in September 1918 its directors accepted, and the War Ministry assigned six million marks for the project.

After Germany’s collapse two months later, Haber and Nernst were branded as war criminals by the Allies, who demanded their extradition. Haber fled to Switzerland, where he was given Swiss citizenship, a privilege reserved for the very rich. After a few months the Allies dropped their demand that he be extradited, and he returned to Germany to help with reconstruction and to continue the secret manufacture of poison gas in violation of the Treaty of Versailles. The Spanish government sought German help in manufacturing and using chemical weapons for suppressing Abd el Krim’s revolt in Morocco. The Soviet government entered into a clandestine agreement with the Germans to manufacture weapons, including poison gas, and the German War Ministry set up a secret chemical warfare factory near Wittenberg. Haber directed these enterprises through his wartime collaborator Dr. Hugo Stoltzenberg, whom Ludwig Haber describes as “a plausible rogue who in other circumstances might have been believed if he had claimed to grow mushrooms in the desert.” In Spain Stoltzenberg set up a poison-gas factory near Madrid and personally advised King Alfonso XIII and his dictatorial prime minister, Primo de Rivera, about the best gas tactics to be employed against the Moroccan rebels.

Hugo Stoltzenberg apparently negotiated contracts allowing him to set up some of the factories as his own private enterprises. In 1925 the German foreign minister, Gustav Stresemann, and his French counterpart, Aristide Briand, met at Locarno and agreed on a rapprochement which induced the German government to stop the secret manufacture of poison gas and to close down Stoltzenberg’s factory. He went bankrupt, but to his fury Haber refused to support his claims for compensation.

Chemical warfare had failed to break the stalemate on the western front, but it had succeeded on the southern front, where the Austrian and Italian armies faced each other near the present frontier between Italy and Slovenia. In my youth in Austria I learned of “our” great victory at Caporetto (now Cobarid in Slovenia) in October 1917, where the Austrian and German armies broke through the Italian lines and advanced seventy miles westward to the River Piave. (The Italian retreat forms the background to Ernest Hemingway’s moving novel A Farewell to Arms.) The books by Stoltzenberg and Ludwig Haber show that the Austrians owed their breakthrough to an attack on the unprotected Italians with a mixture of chlorine and phosgene gas that had been prepared by Otto Hahn and other co-workers of Haber. Otto Hahn’s autobiography suggests that he regretted this later.⁸ In September 1939, after attending a meeting at the German Army Ordnance Department where the possibility of exploiting his discovery of nuclear fission for an atomic bomb was discussed, Hahn declared: “If my work leads to a nuclear weapon, I will kill myself.” He sounded desperate when he heard of Hiroshima during his internment at Farm Hall in England. Fortunately, he would have found it difficult there to carry out his threat, had he still wanted to do so.⁹

Emil Fischer killed himself in 1919 in despair over the loss of his son in the war and over Germany’s defeat and its postwar chaos. It seems that Haber had no regrets. He justified his invention of chemical weapons by claiming that the French had used them first, which was untrue, and that these weapons were more humane than high explosives because most soldiers survived the chemical attacks. He did not mention that many of the survivors were broken in both body and spirit for the rest of their lives. Haber continued until 1933 to advise Germany’s government on its secret production of chemical weapons; but his main energies were devoted to the rebuilding of his institute as a leading center of fundamental research, to the revival of German science, and to the restoration of contacts with scientists abroad. While Haber was overbearing and dictatorial at home, he was wise enough to give his young collaborators scientific freedom. After their seminars he would say apologetically that he may not have been been able to follow all their arguments, and then summarize them more lucidly than they had themselves. The discussions were animated by the search for the scientific truth, regardless of one’s rank or fame. Haber’s institute became again an outstanding center of chemical research, and it still bears his name.

The Treaty of Versailles made Germany’s huge reparations payable in pre-war gold marks, which crippled Germany’s recovery. Haber had read that a ton of sea water contains between five and ten thousandths of a gram of gold, which meant that the oceans might contain as much as eight million tons of it. Once again Haber set out to save Germany single-handed. He decided to devise chemical methods to extract the gold, and to use it to pay Germany’s reparations. In strictest secrecy, he raised money and recruited fourteen young collaborators. Disguised as members of the crew, he and his assistants took a German passenger liner to New York, and then another to Rio. Some of the initial analyses they made on board confirmed the earlier high estimates, but their variability made Haber decide to ship all samples of sea water back for analysis at his Berlin laboratory. After careful analysis of about five thousand samples from sources throughout the world, Haber’s assistant Johannes Jaenicke reported a mean gold content of no more than a thousandth of the original estimates. It was a shattering blow.

In 1917 Haber had married Charlotte Nathan, an attractive, independent, enterprising woman twenty-one years his junior, who lacked his Prussian sense of duty and had a passion for travel. Marriage to a man who was absent from home on important business most of the time and returned exhausted satisfied her as little as it had the very different Clara, and the marriage broke up after ten years. Ludwig Haber, the author of The Poisonous Cloud, is a son of that marriage.

Early in 1933, a few weeks before the Nazis seized power, Haber wrote to a friend: “I fight with ebbing strength against my four enemies, insomnia, the economic claims of my divorced wife, lack of confidence in the future and awareness of the grave mistakes I have committed in my life.” He did not specify the mistakes, but feelings of guilt toward Clara may have been among them.

In April the Nazis ordered that all Jewish civil servants be dismissed, including employees of the Kaiser Wilhelm Gesellschaft. Max Planck, its president, used his official courtesy call on the newly appointed chancellor to plead that Haber and other Jewish scientists be allowed to continue their work. Hitler retorted that he had nothing against the Jews, but that they were all Communists. When Planck remonstrated and pointed out that Germany would harm itself if it expelled all its excellent Jewish scientists, Hitler slapped his knee, talked faster and faster, and whipped himself into such a rage that Planck had to leave the room.

Haber now devoted all his remaining energy to securing work abroad for his Jewish staff. Einstein happened to be visiting the United States, where he stated publicly that he would not return to Germany because it no longer recognized “civil liberty, tolerance and equality of citizens before the law.” The Nazi press responded with a flood of abuse and the commissioner in charge of the Prussian Academy of Sciences demanded that disciplinary action be taken. Planck believed that as a German, Einstein should have stood up for Germany abroad whatever the faults of the new regime and decided that Einstein had made his continued membership of the Academy impossible. When Planck put this view to the assembled members, Haber concurred and only the physicist and Nobel Laureate Max von Laue had the courage to object to the shameful decision. Einstein deeply resented it. When a friend asked him later if he could take greetings from him back to Germany, Einstein replied: “Only to Laue.” “Really no one else?” “No, only to Laue.”

Haber himself eventually fled to Cambridge in England, where the Professor of Chemistry, William Pope, his adversary in chemical warfare, received him with honors, but the laboratory technicians who had fought in the trenches shunned him. After a short stay, Haber traveled to Switzerland, where he died of a heart attack after his arrival in Basel in January 1934, aged only sixty-five.

Had he lived, he would have had to face the most gruesome of his mistakes, to which Tony Harrison alludes in Square Rounds, when Clara and a veiled chorus sing:

He’ll never live to see his fellow Germans use
his form of killing on his fellow Jews.

In 1919, when Allied inspectors of his institute prevented further research on chemical warfare against human beings, Haber turned to chemical warfare against agricultural pests. He became National Commissioner for Pest Control and founded a new firm, the German Society for Pest Control. The firm developed a preparation combining hydrocyanic acid, which is highly toxic, with asweet-smelling, volatile, nontoxic irritant; both were absorbed in a porous powder. Another firm, Tesch and Stabonov, undertook to spread the powder in insect-contaminated fields and buildings. When it was spread on an open field, the acid evaporated, killing the insect pests, and the irritant warned people to keep away. The preparation was called Zyklon B. In 1943 Dr. Peters, the director of the pest-control firm, received a secret order from an SS officer to deliver Zyklon B without the irritant to Auschwitz and Oranienburg. He was told that it would be used to kill criminals, incurables, and mentally deficient persons, and he was threatened with the death penalty if he broke the secret. ¹⁰ So the pesticide which began in Haber’s institute ended up as an instrument of the Holocaust, in which some of Haber’s own relations perished.

In 1946 Dr. Tesch, the sole owner of the firm Tesch and Stabonov, was convicted by a British Military Court of delivering Zyklon B to Auschwitz and hanged; ironically, Hugo Stoltzenberg, the secret poison gas manufacturer of the interwar years, was appointed by the British as trustee of the firm. In 1949 a Frankfurt court sentenced Peters to five years in prison for complicity in manslaughter; later, a Wiesbaden court sentenced him to six years for complicity in murder. In 1955 he was acquitted for lack of proof that he had known what was going on at Auschwitz.

Stoltzenberg’s excellent biography is written with scholarly detachment. He confesses that he found it hard to imagine himself in the mind and role of Haber and to understand his unquestioning nationalism and sense of patriotic duty. Stoltzenberg’s documents show that Haber continued to be held in the highest esteem in Germany as a great patriot, scientist, and statesman, despite the widespread public disillusionment with World War I; he also captivated people by his liveliness, charm, Old-World courtesy, and quick repartee. By a terrible irony of fate, it was his apparently most beneficent invention, the synthesis of ammonia, which has also harmed the world immeasurably. Without it, Germany would have run out of explo-sives once its long-planned blitzkrieg against France failed.¹¹ The war would have come to an early end and millions of young men would not have been slaughtered. In these circumstances Lenin might never have got to Russia, Hitler might not have come to power, the Holocaust might not have happened, and European civilization from Gibraltar to the Urals might have been spared.

Haber’s synthesis of ammonia for fertilizer was an extremely important discovery, but, unlike relativity, it did not take a scientist of unique genius to conceive it; any number of talented chemists could, and no doubt would, have done the same work before very long.