Birkeland's scientific career might have turned out differently had he not grown up in a country of mighty rivers. Electricity produced from Norway's hydropower plants was very cheap, and the process that Birkeland invented for synthesizing ammonia depended on low-cost power. Unfortunately, similar conditions did not apply throughout the rest of the world, and other processes soon eclipsed Birkeland's local success.
As a student, Birkeland concentrated on mathematical physics, studying primarily in Paris and Geneva. For a short time, he studied under Heinrich Hertz (1857-1894) in Bonn, Germany.
During the 1890s, Birkeland presented solutions to Scottish physicist James Clerk Maxwell's (1831-1879) equations describing magnetic and electrical forces and fields. He also led three research expeditions that studied the northern lights (aurora borealis), and he founded an observatory for geophysical studies at an extreme northern latitude (70°N).
During the late 1800s and early 1900s, scientists became interested in how "free" (elemental) nitrogen from the atmosphere is "fixed," or combined with other elements. Normally, nitrogen gas is chemically inert, yet nitrogen compounds are found throughout nature. Fertilizers, explosives, and other productsmanufactured from nitrogen compounds were made from limited natural resources, mainly Chile saltpeter (sodium nitrate, or NaNO3), which was imported from the deserts of South America. As these resources began to dwindle,scientists became concerned that without enough nitrogen rich fertilizers toimprove crop yields, agricultural production might fall behind the rate of global population growth.
In the early 1900s, Birkeland and his co-worker Samuel Eyde (1866-1940) invented the first commercially successful process for artificially fixing atmospheric nitrogen. Eyde, whose education was in construction engineering, had been involved in building railway stations and harbors throughout Scandinavia. He was also one of the founders of Norway's electrochemical industry. With such a background, Eyde became interested in entrepreneurial ways to make use ofthe electrochemical industry's expertise. In 1901 Birkeland and Eyde set upa small laboratory for studying electric arc methods of combining atmosphericnitrogen and oxygen into nitrogenoxides.
Their experiments were based on a technique pioneered in 1784 by Henry Cavendish (1731-1810) who had produced nitric acid by passing sparks through a jarof air confined over water. The electricity forced the nitrogen and oxygen inthe air to combine, forming nitrogen dioxide gas, which then dissolved in the water to create nitric acid.
While Eyde secured power supplies and additional financing for the venture from Swedish and French sources, Birkeland focused on the technical aspects ofthe process. They succeeded in developing a practical process and building asmall plant. In the Birkeland-Eyde process, a magnetic field is used to spread the electric arc into a disk of flame. Air is blown into the disk, then mixed immediately with cold air. The process is able to maintain a high-temperature equilibrium.
In 1908, a larger plant using the Birkeland-Eyde arc process was built at Notodden, Norway. Several process modifications were developed, and more plantswere built in other countries as well. But the arc process uses energy inefficiently, making it impractical for most applications.
By 1913, Fritz Haber and Carl Bosch had established a method of fixing nitrogen as ammonia instead of nitrogen oxide. Their ammonia synthesis process finally overshadowed the Birkeland-Eyde method.
Later, Birkeland moved to Egypt, to improve his health and also to pursue hisinterest in astronomy. He attempted to return to Norway during World War I but died en route. Eyde continued to be successful in both business and politics and was appointed Norway's minister to Poland in 1920.
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