No Recantation

In the letter of resignation he wrote that for forty years he had chosen his collaborators by their intelligence and their character and not by their grandmothers. The Civil Service Law of April 1933 required the dismissal of Jewish employees. Fritz Haber, a decorated front-line officer, was personally exempt. His staff were not, and he would not draw up the list. It is the closest thing to a reckoning in the record, and it is not one: nowhere is there a retraction.

Almost every account is built on a hinge: the benefactor of humanity, then the war criminal. This book argues one act. In a Karlsruhe laboratory in 1909 an apparatus built by Robert Le Rossignol dripped liquid ammonia at roughly 125 millilitres an hour; four years later the works at Oppau opened, and within a year it made twenty tonnes a day. Roughly half the nitrogen atoms in a living human body arrived there through that reaction. North of Ypres on 22 April 1915, some 5,730 cylinders holding about 168 long tons of chlorine were opened into the French line at five in the afternoon, and the man who had worked the reaction out stood there to watch. Same laboratory, same method, same conviction, stated all his life: in peacetime a scientist belongs to the world, in war to his country. When the Royal Navy closed the sea lanes in 1914, Haber and Carl Bosch converted the ammonia capacity to munitions. Without that the war ends inside a year.

One chapter is quieter. Clara Immerwahr took a doctorate at Breslau in 1900, the first the university awarded a woman, and stopped doing science when she married. On the night of 1-2 May 1915, in the garden at Dahlem, she shot herself with her husband's service pistol, and their twelve-year-old son reached her first. Haber left for the Eastern Front the next morning. No note is known to survive, two readings circulate, and the book settles neither. He died in a Basel hotel in January 1934, at sixty-five, and the account does not balance.