Fritz Haber, Chemiker, Nobelpreisträger, Deutscher, Jude: Eine Biografie
Der Fall Clara Immerwahr: Leben für eine humane Wissenschaft
“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”
”It was never, ever my intention, to engineer more deaths by my invention.”
”Your process led to death and devastation.”
”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
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.
See his speech later accepting the Nobel Prize, in Les Prix Nobel, 1918 and 1919 (Stockholm: Nobel Foundation, 1920).↩
See Wilhelm Roggersdorf, in cooperation with BASF, In the Realm of Chemistry (Düsseldorf and Vienna: Econ Verlag, 1965).↩