Birkeland, Kristian Olaf Bernhard

[beer kuhlahnt] (1867–1917) Norwegian physicist: devised process for nitrogen fixation.

Birkeland studied physics in Paris, Geneva and Bonn before returning to his native Oslo to teach at the Christiania University. He studied the aurora borealis and in 1896 suggested (correctly) that it resulted from some charged solar radiation becoming trapped in the Earth’s magnetic field near the North Pole. His theory was partly based on an experiment with a magnetized model of the Earth, which he placed in a beam of electrons in a cathode ray tube; he found luminous effects near the poles which resembled aurorae. However, he is best known as co-discoverer of the Birkeland–Eyde process. This was designed to meet the shortage of nitrate fertilizer, and used observation of 1784 that atmospheric nitrogen and oxygen combined in an electric spark to give nitrogen monoxide, NO. The process used an electric arc spread by a magnetic field and the NO was mixed with air and water to give nitric acid; it was used (with the benefit of cheap Norwegian hydro-electricity) from 1903–28.