NICHOLSON, JOHN WILLIAM

(b. Darlington, England, 1 November 1881; d. Oxford, England, 10 October 1955)

mathematical physics, astrophysics.

The eldest son of John William Nicholson and Alice Emily Kirton, Nicholson received his early education at Middlesbrough High School. He studied mathematics and physical science at the University of Manchester from 1898 to 1901. He went on to Trinity College, Cambridge, where he took the mathematical tripos in 1904. At Cambridge he was Isaac Newton student in 1906, Smith’s prizeman in 1907, and Adam’s prizeman in 1913 and again in 1917. He lectured at the Cavendish Laboratory, Cambridge, and later at the Queen’s University, Belfast, before being appointed professor of mathematics at King’s College, London, in 1912. In 1921 he became fellow and director of studies in mathematics at Balliol College, Oxford, retiring in 1930 because of bad health. In 1922 he married Dorothy Wrinch, fellow of Girton College, Cambridge; they had one daughter. Their marriage was dissolved in 1938.

Nicholson became fellow of the Royal Astronomical Society in 1911 and fellow of the Royal Society in 1917. He was vice-president of the London Physical Society, president of the Röntgen Society, and member of the London Mathematical Society and the Société de Physique. He received the M. A. from the universities of Oxford and Cambridge, the D. Sc. from the University of London, and the M. Sc. from the University of Manchester.

Nicholson’s most original work was his atomic theory of coronal and nebular spectra, which he published in a series of papers, beginning in November 1911, in the Monthly Notices of the Royal Astronomical Society. The spectra of the solar corona and galactic nebulae contained lines of unknown origin, which Nicholson, following a common astrophysical speculation at the time, supposed were produced by elements that were primary in an evolutionary sense to terrestrial elements. The presumed simplicity of the primary elements opened the possibility of their exact dynamical treatment. Adapting an atomic model of J. J. Thomson, Nicholson viewed an atom of a primary element as a single, planetary ring of electrons rotating about a small, massive, positively charged nucleus. Associating the frequencies of the unidentified spectral lines with those of the transverse modes of oscillation of the electrons about their equilibrium path, he accounted for most coronal and nebular lines with impressive numerical accuracy, even predicting a new nebular line that was soon observed.

In his first two papers on celestial spectra, Nicholson had no theoretical means for fully specifying his atomic systems, having to fix empirically the radius and angular velocity of the electron rings from observed spectral frequencies. In his third paper (June 1912) he rectified the incompleteness of his theory by introducing the Planck constant, h. He did so by observing that the angular momentum of primary atoms was a multiple of h/2π. Niels Bohr read Nicholson’s papers in the Monthly Notices in late 1912, at the time he was working out his own early thoughts on the relation of the Planck constant to the structure of atoms and molecules. Impressed by the unprecedented spectral capability of Nicholson’s theory, Bohr sought its relation to his own theory. In so doing Bohr came to a deeper understanding of his own atomic model, in particular of his need to attribute excited states to it. After Bohr published his theory in 1913, Nicholson challenged it and extended his own theory. But it was Bohr’s theory and not his that led to a full understanding of spectra and beyond that to a new quantum atomic physics. The significance of Nicholson’s theory for the development of twentiethcentury atomic physics lies chiefly in the early impetus it gave Bohr for exploring the spectral implications of his very different quantum theory.

BIBLIOGRAPHY

I. Original Works. Nicholson’s active career spanned the years 1905–1925, during which he published roughly seventy-five papers. His most important papers on coronal and nebular spectra are “The Spectrum of Nebulium,” in Monthly Notices of the Royal Astronomical Society, 72 (1911), 49–64; and “The Constitution of the Solar Corona,” ibid., 139–150; ibid. (1912), 677–692, 729–739. In addition to his astrophysical papers, Nicholson published on a wide range of topics that included electric and elastic vibrations, electron theory of metals, electron structure, atomic structure and spectra of terrestrial elements, relativity principle, and special mathematical functions.

Although Nicholson wrote no books, he contributed to Arthur Dendy, ed., Problems of Modern Science. A Series of Lectures Delivered at King’s College—University of London (London, 1922). He collaborated with Arthur Schuster in revising and enlarging the third ed. of the latter’s An Introduction to the Theory of Optics (London, 1924); and with Joseph Larmor et al. he edited the Scientific Papers of S. B. McLaren (Cambridge, 1925).

II. Secondary Literature. Nicholson’s contribution to modern atomic theory has been recently assessed by John L. Heilbron and Thomas S. Kuhn, “The Genesis of the Bohr Atom,” in Historical Studies in the Physical Sciences, 1 (1969), 211–290; T. Hirosige and S. Nisio, “Formation of Bohr’s Theory of Atomic Constitution,” in Japanese Studies in the History of Science, no. 3 (1964), 6–28; and Russell McCormmach, “The Atomic Theory of John William Nicholson,” in Archives for History of Exact Sciences,3 (1966), 160–184.

In his introduction to Niels Bohr, On the Constitution of Atoms and Molecules (Copenhagen, 1963), xi-liii, Léon Rosenfeld has, in addition to discussing Nicholson’s theory, published and analyzed letters by Bohr in 1912 and 1913 that bear on his reading of the theory. An older historical discussion of Nicholson’s theory is Edmund Whittaker, A History of the Theories of Aether and Electricity. The Modern Theories 1900’1926 (London, 1953), 107. A contemporary scientific account of Nicholson’s theory is W. D. Harkens and E. D. Wilson, “Recent Work on the Structure of the Atom,” in Journal of the American Chemical Society,37 (1915), 1396–1421.

For biographical information, see William Wilson, “John William Nicholson 1881-1955,” in Biographical Memoirs of Fellows of the Royal Society, 2 (1956), 209–214.

Russell McCormmach