Joseph Norman Lockyer

English astrophysicist

• Born: May 17, 1836
• Birthplace: Rugby, Warwickshire, England
• Died: August 16, 1920
• Place of death: Salcombe Regis, Devonshire, England

A pioneering, self-educated astrophysicist, Lockyer founded the world’s premier general science periodical, the weekly journal Nature, which he edited throughout its first fifty years.

Early Life

Joseph Norman Lockyer was the son of Joseph Hooley Lockyer, a surgeon-apothecary in Rugby. His mother, who had been born Anne Norman, was the daughter of the squire of a Warwickshire village near Rugby. He had one sibling, a younger sister, and he was called Norman as he was growing up.

Lockyer’s father had broad scientific interests and had been a founding member of the Rugby Literary and Scientific Institution. As a teenager, Lockyer’s principal interest at school was not science but languages, especially Latin and Greek. In 1856, at the age of twenty, he went to the Continent for a year to study French and German. Upon his return to England, Lockyer obtained a temporary position at the War Office in May, 1857. In February of the following year he was appointed to a permanent clerkship in the War Office and appeared destined for a career in the civil service. In the same year he married Winifred James, whose father, William, had an important role in the early development of English railroads. Winifred possessed, as did her husband, an excellent knowledge of the French language, and after her marriage she became known as a translator of French scientific texts.

The Lockyers’ first home was in the village of Wimbledon, an easy commute by train to London and the War Office. The Lockyers had nine children, seven boys and two girls, before Winifred died in 1879. Twenty-four years later, in 1903, Lockyer married Thomasine Mary Brodhurst, the fifty-year-old widow of a surgeon. She outlived Lockyer and after his death published a volume on Lockyer’s life and work.

Lockyer was an energetic and forceful personality of medium height, somewhat thickset, who did not shrink from controversy. He was ambitious and an exceedingly hard worker, driving himself on several occasions to the point where he required a complete respite from work; nevertheless, he also enjoyed a variety of leisure activities, particularly golf, for which he coauthored The Rules of Golf (1896).

Life’s Work

Lockyer’s transformation from obscure War Office clerk to internationally known editor and scientist began in Wimbledon, where, influenced by new acquaintances, he took up astronomy as a hobby, purchasing a three-and-three-quarters-inch refracting telescope and becoming a fellow of the Royal Astronomical Society in 1861. On May 10, 1862, the London Review published his account of his observations of the transit of the shadow of Saturn’s moon Titan across the planet’s disc. The London Review’s editor subsequently invited Lockyer to submit an article each month under the title “Face of the Sky.” Lockyer regarded this series as the beginning of his literary work.

Lockyer also became science editor and writer for the Reader, a new literary and scientific journal. When the Reader foundered after only a few years, Lockyer envisioned a weekly journal devoted exclusively to science. His idea appealed to the publisher Alexander Macmillan, and Nature was launched on November 4, 1869. Nature experienced financial difficulties in its early years, but thanks to Lockyer’s enthusiasm and Macmillan’s continued support it survived, showing a profit for the first time in 1899 and going on to become the world’s most respected general scientific journal in the twentieth century and Lockyer’s most lasting contribution. Lockyer was its editor throughout its first fifty years.

When the British government named a Royal Commission on Scientific Instruction and the Advancement of Science in 1870, Lockyer was delighted to be summoned from the War Office to be its secretary, a position he held until the commission issued its final report in 1875. The experience gave him a comprehensive knowledge of the strengths and weaknesses of science in Great Britain. Throughout his adult life he was an advocate of the state support of science. Upon the completion of the commission’s work, Lockyer did not return to the War Office, being appointed instead to the government’s Science and Art Department with responsibility for arranging an exhibition of significant laboratory and scientific teaching apparatus at London’s South Kensington Museum.

Opened by Queen Victoria in 1876, the exhibition was a great success. In addition to arranging the exhibition, Lockyer was expected by the department to continue his by then significant astrophysical researches, and so he established a small government observatory, soon to be known as the Solar Physics Observatory. When in 1878 the government created a Solar Physics Committee, Lockyer sat on it as representative of the Science and Art Department. Nine years later, the committee became an advisory and supervisory board for the Solar Physics Laboratory still directed by Lockyer. Since 1881, Lockyer had taught astronomy at the Normal School of Science and the Royal School of Mines (renamed the Royal College of Science in 1890) in London. He was promoted to professor of astronomical physics in 1887.

While earning his livelihood in these various positions, Lockyer had from the 1860’s pursued, frequently in his spare time, his research interests in the new field of astrophysics. In 1859, Robert Bunsen and Gustav Robert Kirchhoff, professors of chemistry and physics, respectively, at the University of Heidelberg in Germany had founded spectrum analysis on the principle that each element has its characteristic spectrum.

During the following year Kirchhoff had given an explanation of the dark, or Fraunhofer, lines in the solar spectrum, thereby revealing the chemical composition of the sun and at the same time initiating the science of astrophysics. Lockyer quickly became attracted to this new branch of astronomy—which utilized the new instrument the spectroscope, and also the camera, together with the traditional telescope—and just as quickly began to make his mark in it. During the early 1860’s, a dispute had arisen concerning whether spots on the sun were hotter or cooler than the surrounding solar surface.

Lockyer devised a means of spectroscopically examining the light from individual sunspots, as opposed to the entire solar disc, and established that the spots are cooler than their surroundings. He then turned to a study of solar prominences, bright clouds of matter that were observed during solar eclipses to rise from the sun’s surface into its corona, or atmosphere. Employing the method that he had devised for examining individual sunspots, Lockyer demonstrated in 1868 that prominences could be studied with the spectroscope at times other than solar eclipses, and, further, that, because of their bright line spectra, prominences were clouds of hot gas. Unknown to Lockyer, this conclusion had been independently reached by the French astrophysicist Pierre Jules César Janssen, using a similar method, a few weeks earlier. The French government honored Janssen’s and Lockyer’s simultaneous discovery by striking a medal with their portraits on it. On the strength of his original contributions to solar physics, Lockyer was elected a fellow of the Royal Society, Great Britain’s most prestigious scientific society, in 1869.

Lockyer’s further spectroscopic and astrophysical researches led him to formulate two bold hypotheses for which he became widely known. The first hypothesis concerned the dissociation of matter. At the time, during the 1870’s, the concepts of atom and molecule (a combination of two or more atoms) were found to be useful in chemistry and certain branches of physics. For example, gaseous hydrogen was regarded as comprising hydrogen molecules, each consisting of two hydrogen atoms; the two spectra found in the laboratory to be characteristic of hydrogen, a band spectrum and a line spectrum, were attributed to the molecular and atomic forms of hydrogen, respectively.

It was believed that as the temperature of the hydrogen gas was increased, the molecules of hydrogen became dissociated into atoms, and so the band spectrum became replaced by the line spectrum. In the astrophysical realm, red stars, believed to be of relatively low temperature, exhibited band spectra; yellow stars, of higher temperature, such as the Sun, exhibited the line spectra of numerous elements, including the heaviest; and white stars, believed to be of yet higher temperature, displayed the line spectrum of the simplest element of all, hydrogen. From these and from other observations, Lockyer hypothesized in 1873 that with increasing stellar temperature heavier elements became dissociated into lighter ones and their common constituents.

In considering the constitutions of elemental atoms, Lockyer suggested an analogy with the composition of members of a hydrocarbon series that organic chemists had shown could be built up through successive additions of the radical CH². Earlier in the nineteenth century, a British physician, William Prout, had hypothesized that the hydrogen atom might be the building block of all other atoms.

At the annual meeting of the British Association for the Advancement of Science in 1879, Lockyer announced that he had been successful in partially decomposing several elements into hydrogen in the laboratory. Chemists were not convinced, however, and even though astrophysicists continued to support the dissociation hypothesis during the 1880’s, by the end of the century they, too, had concluded that it was untenable. About that time a quite different view of atomic composition was beginning to take shape following Joseph John Thomson’s discovery in 1897 of the astonishingly small particle, some two thousand times smaller than the hydrogen atom, soon to be known as the electron. In The Chemistry of the Sun (1887) Lockyer summarized his ideas on dissociation and answered criticisms of the dissociation hypothesis. He published a revised version of the hypothesis in Inorganic Evolution as Studied by Spectrum Analysis (1900).

In connection with the dissociation hypothesis, Lockyer had been unable to determine the constituents of atoms, but with the much grander meteoritic hypothesis he specified that meteors were the building blocks of the visible universe. As he claimed, “all self-luminous bodies in the celestial spaces are composed either of swarms of meteorites or of masses of meteoritic vapour produced by heat.”

In 1866, two striking astronomical phenomena, a nova and the Leonid shower of meteors, greatly impressed Lockyer. He speculated that the phenomena might be related, that a nova might result from the collision of showers of meteors. Later, in 1874, in viewing Coggia’s comet Lockyer adopted the idea, not original with him, that a comet consists of a shower of meteors whose frequent, mutual collisions cause the comet’s luminosity. The spectroscopic study in the laboratory of available meteorites strengthened Lockyer’s belief in the meteoritic nature of comets.

When the first nova to be examined systematically using the spectroscope developed a spectrum characteristic of a nebula in 1877, Lockyer argued that the observed spectroscopic changes could be interpreted as the result of a gradual cooling of meteors from the intense heat of their impact to the cooler state of a nebula. Hitherto, Lockyer had, like others, assumed nebulas to be the hottest bodies in the universe, which in cooling developed into stars that continued to fall in temperature over time. Now, on spectroscopic grounds, Lockyer argued that nebulas developed into cool stars that, on condensing, rose in temperature before becoming cool once more. He was aware that the teaching of the accepted view of stellar evolution, that stars are born hot and cool throughout their lives, ran against his argument.

Principally because of this disagreement with the prevailing view, the meteoritic hypothesis lost support among astrophysicists and perished. Lockyer published his views on stellar evolution in The Meteoritic Hypothesis (1890) and his further development of the meteoritic hypothesis in The Sun’s Place in Nature (1897). Inorganic Evolution as Studied by Spectrum Analysis (1900) was the last of Lockyer’s books to deal with both the meteoritic and the dissociation hypotheses.

During a visit to Greece and Turkey early in 1890, Lockyer became curious about the orientations of ancient temples. Later, in studying Egyptian temples, to which most of the available data referred, he argued that if their orientations had an astronomical basis, then determination of the orientations could lead to establishing the dates of construction of the temples. Lockyer determined that several temples at Karnak were oriented toward either the rising or the setting solstitial sun, while the pyramids and temples at Giza were oriented toward the equinoctial sun. He calculated that the temple of Amen-Ra at Karnak had been built about 3700 b.c.e.

Lockyer found that some temples were not oriented toward the sun, but instead toward bright stars, including Sirius. Lockyer went on to apply his ideas on orientation to Stonehenge and other ancient stone monuments in Great Britain. He concluded that they could be arranged in an evolutionary order: Avenues and cromlechs came first, and stone circles, representing a more advanced state of astronomical knowledge, came later. He believed that the sunrise orientations used in the earlier stage were related to the appearance of new vegetation in May, whereas those of the later stage were related to the summer solstice in June. In dealing with both Egyptian temples and British monuments, Lockyer made speculative, and controversial, excursions into mythology and folklore. His conclusions regarding the orientations of Egyptian temples were published in The Dawn of Astronomy: A Study of the Temple Worship and Mythology of the Ancient Egyptians (1894) and his views on British stone structures in Stonehenge and Other British Monuments Astronomically Considered (1906).

In 1901, Lockyer was obliged to retire from the Royal College of Science because of age regulations, but he continued as director of the Solar Physics Laboratory until 1911, when it was decided, to his profound disappointment and against his vigorous opposition, to transfer the observatory to Cambridge University. Lockyer’s response to the transfer was to build an observatory at Sidmouth in Devonshire, which he directed until his death in 1920.

Significance

Joseph Norman Lockyer was a self-educated and widely known man of broad interests, including scientific publishing, astrophysics, ancient astronomy, meteorology, education, the state support of science, and golf. During his busy life he played many roles, including those of civil servant, secretary to a royal commission on science, professor of astronomy, director of astronomical observatories, fellow of the Royal Society, president of the British Association for the Advancement of Science, and founder of the British Science Guild. Finally, he made substantial contributions: He was a leading astrophysicist, a sound experimentalist, and a bold theorizer, and he founded and edited Nature, which remains the world’s foremost general scientific periodical. Lockyer’s positive influence was felt by international scientists, British scientific institutions, the field of astrophysics, science in general, and even scholars and fields outside science. In recognition of his services to science in Great Britain, Lockyer was knighted in 1897.

Bibliography

Chapman, Allan. The Victorian Amateur Astronomer: Independent Astronomical Research in Britain, 1820-1920. New York: John Wiley & Sons, 1998. Information about Lockyer’s astronomical discoveries is included in this book about the work and significance of amateur astronomers in nineteenth century Britain.

Clerke, Agnes M. A Popular History of Astronomy During the Nineteenth Century. Edinburgh: A and C Black, 1885. Reprint. Decorah, La.: Sattre Press, 2003. The second part, “Recent Progress of Astronomy,” provides useful accounts of various aspects of astrophysics during its first twenty-five years.

Lockyer, T. Mary, and Winifred L. Lockyer, with the assistance of Prof. H. Dingle. Life and Work of Sir Norman Lockyer. London: Macmillan, 1928. This volume consists of a chronology of Lockyer’s life by Dingle based on materials gathered by Lockyer’s second wife, Mary, and younger daughter, Winifred, and a series of useful essays on aspects of Lockyer’s work, for example the dissociation hypothesis, not explained in the chronology.

McGucken, William. Nineteenth-Century Spectroscopy: Development of the Understanding of Spectra, 1802-1897. Baltimore: Johns Hopkins University Press, 1969. The second chapter, “Atoms and Molecules and the Further Extension of the Principle of Spectrum Analysis,” includes a detailed discussion of Lockyer’s dissociation hypothesis.

Meadows, A. J. Early Solar Physics. Oxford, England: Pergamon Press, 1970. Provides a good account of the development of solar physics during the second half of the nineteenth century. Reproduces original papers, including several by Lockyer, that contributed to that development.

‗‗‗‗‗‗‗. Science and Controversy: A Biography of Sir Norman Lockyer. Cambridge, Mass.: MIT Press, 1972. This is the better of the two accounts of Lockyer’s life and work. Although the author occasionally lapses into a chronological account, he enables the reader to see Lockyer within the context of his times. He also presents a fuller, more critical account of Lockyer the man.