See biographies by M. H. Goran (1967) and D. Charles (2005).
(born Dec. 9, 1868, Breslau, Silesia, Prussia—died Jan. 29, 1934, Basel, Switz.) German physical chemist. After early research in electrochemistry and thermodynamics, he developed, with his brother-in-law Carl Bosch (1874–1940), the Haber-Bosch process for making ammonia. Intensely patriotic, he directed Germany's World War I chemical-warfare efforts, under which poison gas was introduced. His versatility and his wide-ranging and important work brought him fame and honour, and he was awarded a 1918 Nobel Prize. In 1933 the Nazi Party's anti-Semitic policies led him to resign as head (since 1911) of the Kaiser-Wilhelm Institute.
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Haber's rule states that, for a given poisonous gas, , where is the concentration of the gas (mass per unit volume), is the amount of time necessary to breathe the gas, in order to produce a given toxic effect, and is a constant, depending on both the gas and the effect. Thus, the rule states that doubling the concentration will halve the time, for example.
Haber's rule is an approximation, useful with certain inhaled poisons under certain conditions, and Haber himself acknowledged that it was not always applicable. It is very convenient, however, because its relationship between and appears as a straight line in a log-log plot. In 1940, statistician C. I. Bliss published a study (Bliss, 1940) of toxicity in insecticides in which he proposed more complex models, for example, expressing the relationship between and as two straight line segments in a log-log plot. However, because of its simplicity, Haber's rule continued to be widely used. Recently, some researchers have argued (Miller et al., 2000) that it is time to move beyond the simple relationship expressed by Haber's rule and to make regular use of more sophisticated models.