A Breslau childhood
Fritz Jakob Haber was born on 9 December 1868 in Breslau, in Prussian Silesia (today Wrocław, Poland), into a prosperous Jewish merchant family long established in the city. His father, Siegfried, ran a business in dyes, paints and pharmaceuticals; his mother, Paula, Siegfried’s first cousin, died three weeks after Fritz was born. The loss shadowed his relationship with his father, which remained distant and often strained, though he grew close to his stepmother, Hedwig Hamburger, and his three half-sisters.
The Habers were, like many Breslau Jews of their generation, largely assimilated. They supported the Jewish community and kept many Jewish traditions without being closely tied to the synagogue, and Fritz attended schools where Jewish and Christian pupils studied side by side. From early on he identified intensely as a German, far more than as a Jew, a fact that would give his life its tragic shape.
A restless education
After finishing at the St Elizabeth gymnasium in 1886, Haber studied chemistry in Berlin under A. W. Hofmann, in Heidelberg under Robert Bunsen, and at the Technische Hochschule in Charlottenburg under Carl Liebermann, earning his doctorate in organic chemistry in 1891. He did a year of military service, worked in his father’s firm and in several industrial plants, and studied chemical technology in Zurich. Father and son clashed constantly over the business, and eventually Siegfried told him he belonged back in the university.
In the early 1890s, while working as an assistant at the University of Jena, Haber was baptised and became a Lutheran. Like many Jews of the time, he may have hoped that conversion would open academic and military doors that remained closed to Jews. In 1894 he moved to Karlsruhe, which would be his scientific home for seventeen years.
The physical chemist of Karlsruhe
At Karlsruhe Haber taught himself the young discipline of physical chemistry and became one of its leaders. He studied the breakdown and combustion of hydrocarbons, wrote an influential textbook on technical electrochemistry in 1898, showed how controlling the electrode potential could produce specific reduction products, helped invent the glass electrode used to measure acidity, and in 1905 published a celebrated book on the thermodynamics of technical gas reactions. He became a full professor in 1906.
In 1901 he married Clara Immerwahr, the first woman to earn a doctorate in chemistry at the University of Breslau, who, like him, had converted from Judaism to Christianity. Their son, Hermann, was born in 1902. Clara found little room for her own scientific career in the marriage, and she grew increasingly unhappy.
Bread from air
Nitrogen is essential to every living thing and makes up most of the air, but plants cannot use it in its atmospheric form. At the turn of the twentieth century farmers depended on limited natural sources of fixed nitrogen, above all Chilean saltpetre and guano, and scientists warned that the world would soon run short. Haber set out to make ammonia directly from nitrogen and hydrogen. In 1909, with his assistant Robert Le Rossignol, he succeeded in a tabletop apparatus, circulating the gases over a catalyst at around 500 degrees Celsius and very high pressure.
The chemical company BASF bought the process, and its engineer Carl Bosch, with Alwin Mittasch, turned it into an industrial operation, finding cheaper iron-based catalysts and building giant high-pressure reactors. The first plant opened at Oppau in 1913. The Haber–Bosch process made synthetic nitrogen fertiliser cheap and abundant. Today more than 100 million tonnes of synthetic nitrogen fertiliser are produced each year, and estimates suggest that the food grown with it supports roughly half of humanity. Few inventions have touched more lives.
Dahlem and the war of the chemists
In 1911 Haber became founding director of the new Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry in Berlin-Dahlem, one of the most important research centres in Europe. When war came in 1914 he threw himself and his institute into the German war effort. He signed the Manifesto of the Ninety-Three, in which leading intellectuals defended Germany’s conduct. His ammonia process now served war as well as farming: with Chilean nitrates cut off by the British blockade, synthetic ammonia supplied Germany with the nitric acid needed for explosives.
Haber went further. He became head of the War Ministry’s chemistry section, was commissioned a captain, and proposed releasing chlorine gas from cylinders to break the deadlock of the trenches, despite the Hague Convention’s prohibition on poison projectiles. He assembled a team that grew to more than 150 scientists and some 1,300 technical staff, among them future Nobel laureates James Franck, Gustav Hertz and Otto Hahn. On 22 April 1915, at the Second Battle of Ypres, he was present as German troops released chlorine against French and colonial troops, the first large-scale use of poison gas in modern war. His teams went on to develop further gases and the gas masks to protect against them, and he defended gas warfare as no more cruel than shells and bullets. He is often called the father of chemical warfare.
Clara
On the night of 1–2 May 1915, days after Ypres, Clara Immerwahr shot herself in the garden of their Dahlem home with her husband’s service pistol; their thirteen-year-old son found her. Her reasons remain debated. She was deeply unhappy in her marriage, and some accounts hold that she opposed his gas work, although direct evidence is limited. Haber left for the Eastern Front shortly afterwards to oversee gas attacks against Russian forces.
In 1917 he married Charlotte Nathan, who also converted from Judaism before the wedding; they had two children, Eva and Ludwig, and divorced in 1927. Ludwig Fritz Haber became a British economic historian and wrote The Poisonous Cloud (1986), a history of gas warfare in the First World War. Hermann, Clara’s son, fled France for the United States during the Second World War and took his own life in 1946.
A disputed Nobel, a broken peace
Haber was awarded the 1918 Nobel Prize in Chemistry, presented in 1919, for the synthesis of ammonia. The award caused consternation among scientists in the countries Germany had fought. After the war he remained involved in Germany’s covert chemical-weapons work until the early 1920s. He also tried, for years, to extract gold from seawater to help pay Germany’s reparations, and concluded with deep disappointment that it could not be done economically.
In the 1920s he rebuilt his Dahlem institute into a world centre for physical chemistry and atomic physics, appointing department heads such as James Franck, Michael Polanyi and Herbert Freundlich, and worked to restore Germany’s ties with foreign science. His scientific range remained wide: with Max Born he devised the Born–Haber cycle for calculating the energy of ionic crystals, he invented a firedamp whistle to warn miners of explosive gas, and his observations on adsorption helped inspire Irving Langmuir’s theory of the subject. Strikingly, given his war record, he also served on the League of Nations committee on chemical warfare. Scientists at the institute developed a cyanide-based pesticide, Zyklon A. Years later, without Haber’s involvement, the related product Zyklon B would be used by the Nazis to murder more than a million people, most of them Jews, in the gas chambers. Several members of Haber’s own extended family were murdered in the Holocaust.
The tragedy of the German Jew
None of his service protected him. In April 1933 the Nazi civil-service law ordered the dismissal of Jewish employees. As a baptised war veteran Haber could legally have stayed, but he refused to dismiss his staff and remain himself; on 30 April he resigned, effective October, writing that he no longer wished to serve. Nazi publications attacked him as a Jew. He spent his last months searching for positions for his dismissed colleagues while his own health, long weakened by heart disease, failed.
He went first to Paris and Spain, then to Cambridge, where British chemists who had been his wartime enemies arranged an invitation; Ernest Rutherford, still repelled by the gas warfare, refused to shake his hand. Chaim Weizmann, the Zionist leader and chemist, offered him the directorship of the Sieff Research Institute in Rehovot, in Palestine, and Haber accepted. On the way, on 29 January 1934, he died of heart failure in a hotel in Basel, aged sixty-five.
A double legacy
Haber left his library to the Sieff Institute, now the Weizmann Institute of Science, where it was dedicated as the Fritz Haber Library in 1936. His ashes were buried in Basel’s Hörnli cemetery, and at his wish Clara’s remains were later moved to lie beside him. In 1953 the Dahlem institute was renamed the Fritz Haber Institute of the Max Planck Society, and Israeli and German scientists collaborate today through a Fritz Haber research centre at the Hebrew University of Jerusalem.
His friend Albert Einstein, who had condemned his war work, wrote that Haber’s life was the tragedy of the German Jew, the tragedy of unrequited love. That judgement captures only part of a contradictory figure. The same chemist whose ammonia synthesis keeps billions of people fed also pioneered the weapons that choked soldiers at Ypres; the man who abandoned Judaism for Germany was cast out by Germany as a Jew. Historians, scientists and ethicists still return to his story as one of the starkest examples of how science can serve both life and death.
Sources & further reading
Fritz Haber, Wikipedia · Fritz Haber, Biographical, NobelPrize.org · Fritz Haber, Science History Institute · Fritz Haber, Nobel Lecture (1920), NobelPrize.org · Researched from the sources above and checked against them. Spotted an error? Tell us.
A life of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.