Huggins, William

(b. London, England, 7 February 1824; d. Tulse Hill, London, 12 May 1910)

astrophysics.

Huggins was the second and only surviving child (the first had died in infancy) of William Thomas Huggins, a silk mercer and linen draper in Grace-church Street in the City of London. His mother, the former Lucy Miller, was a native of Peterborough. He was precocious and, after a short period of attendace at a small nearby school and instruction at home under the curate of the parish, he entered the City of London School at its opening early in 1837. An attack of smallpox, from which he fully recovered, led to his removal from the school shortly afterward, his eductation being continued by private tutors at home. Although his formal instruction was broad including classics, several modern languages, and music, his predominant interest was in science. A gift of a microscope led to early concentration on physiology, and although at about the age of eighteen he bought his first telescope—for £15—his location in the City of Lond was too unsuitable for celestial observations to allow astronomy to claim much of his attention.

At about this time (1842) family circumstances led to a regretful decision to abandon his intention of going to Cambridge for a university education, and he took over the responsibility for his father’s business. From then until 1854 this was his chief concern, although his spare time was almost wholly given to the microscope and the telescope. Visits to the Continent, where his knowledge of languages stood him in good stead, helped to preserve the balance of his interests.

In 1852 Huggins joined the Royal Microscopical Society and in 1854 the Royal Astronomical Society, and in the latter year he was able to dispose of the mercery business and thereafter devote his whole time to science. He removed with his parents to Tulse Hill—now a part of greater London, but then situated in the country—and in the new surroundings astronomy prevailed over microscopy as his major interest. A not unimportant factor in this choice was his sensitive nature, which made experiments on animals distasteful to him. Huggins remained at Tulse Hill for the remainder of his life, setting up an observatory equipped with instruments, partly purchased by himself and partly lent by the Royal Society, and here the whole of his astronomical researches were carried out.

His father died shortly after the removal to Tulse Hill, but his mother survived until 1868; he felt her loss keenly. In 1875 he married Margaret Lindsay Murray, of Dublin, who, although twenty-six years his junior, was an ideal partner for the next thirty-five years, taking an active poart in the astronomical observations; her name is associated with his in the authoriship of some of his cheif publications. She seems, indeed, in this respect to have stood in a relation to her husband similar to that of Caroline Herschel to her brother William. She had also considerable artistic and musical gifts.

Huggins, although other interests ranked far below astronomy in his esteem, was by no means narrow-minded. He was an able violinist—according to his wife, “always rather an intellectual than a perfervid player”—and owned a fine Stradivarius instrument. Presumably it was the intellectual element in his musical talent that led to his contributing to the Royal Society in 1883 a paper on the proportional thickness of the strings of the violin—apparently his only publication, apart from one or two early papers on microscopical work, that was not astronomical in character. He was an expert pike fisherman and an admirer of Izaak Walton. Huggins had been brought up as a Calvinist but had never responded to this form of religion, and his views on such matters are perhaps best indicated by his wife’s description of him as a “Christian unattached.” For a short time in 1870 he was attracted toward the scientific study of spiritualism and corresponded with Sir William Crookes on the subject, but his experience at séances led him to the conclusion that the subject was too closely associated with trickery to merit his serious attention.

Huggins’ pioneer work in astrophysics brought him many honors. In 1865 he was elected a fellow of the Royal Society, and in the following year was awarded one of its Royal Medals. The Rumford and Copley Medals of the Royal Society followed in 1880 and 1898, respectively. In 1900 he became president of the Royal Society, a position which he occupied for the customary five years. His annual addresses in this capacity were collected and published in 1906 in a volume entitled The Royal Society, or Science in the State and in the Schools; here they were supplemented by many illustrations and material dealing with the history of the Royal Society and closely related matters. Huggins received the gold medal of the Royal Astronomical Society, jointly with W. A. Miller in 1867 and as the sole recipient in 1885; he was president of the Royal Astronomical Society during the two sessions 1876–1878. In 1891 he was president of the British Association for the Advancement of Science, and in 1897 he was created a K.C.B. and in 1902 awarded the O.M., one of the original members of the Order of Merit, which had just been instituted. Numerous universities conferred honorary degrees on him. His financial resources, although sufficient to allow him to devote the whole of his time to astronomy, were not great; and in 1890 he was awarded a Civil List pension of £150 a year in recognition of the value of his work.

In 1908, when he felt no longer able to continue his researches, Huggins returned his instruments to the Royal Society; and they were transferred to the Solar Physics Observatory at Cambridge, where they now are. He died on 12 May 1910, following an operation.

Huggins’s earliest astronomical work was on conventional lines. He formed a close friendship with W. R. Dawes, a well-known amateur observer, from whom he bought an eight-inch refracting telescope; and with this, between 1858 and 1860, he made observations of the dark Fraunhofer lines in the solar spectrum, the chemical composition of the sun’s atmosphere could be determined; and Huggins gave the first manifestation of one of his most marked characteristics—that of immediately perceiving the possibilities opened up by a new discovery. “like the coming upon a spring of water in a dry and thirsty land.” It at once occurred to him that this method could be applied to the stars; and he confided his idea to his friend W. A. Miller, professor of chemistry at King’s College, London, who, although somewhat dubious, agreed to collaborate with him. They designed a spectroscope consisting of two dense flint glass prisms which they attached to Huggins’ eight-inch telescope, and observations of stellar spectra were begun. The same idea had occurred to Rutherford in America, but quite independently. In order to interpret the stellar spectra it was necessary to obtain better knowledge than that which then existed of the spectra of terrestrial elements; and maps of twenty-four such spectra were prepared by Huggins, with the use of a more powerful spectroscope containing six prisms. In 1863–1864 the stellar and laboratory observations were published by the Royal Society, the general conclusion reached being that the brightest stars, at least, resembled the sun in structure, in that their light proceeded from underlying hot material and passed through an atmosphere of absorbent vapors; nevertheless, there was considerable diversity of chemical composition among the stars.

Striking as this conclusion was—much more so then than now, when it has become a commonplace—a still more sensational discovery was made in 1864. The nature of the nebulae was then quite unknown: “a shining fluid of a nature unknown to us,” which was William Herschel’s description of a nebula, had remained all that could safely be said on the matter. The fact that an increasing number of them had, after Herschel’s time, been resolved into star clusters as more powerful telescopes became available, had led to the conjecture that all were of this character and would be so observable with instruments of sufficient resolving power. It occurred to Huggins to attempt a verification of this by observation with the spectroscope. He accordingly directed his instrument toward a planetary nebula in the constellation Draco and observed not, as he expected, a mixture of stellar spectra but a few isolated bright lines. His knowledge of laboratory spectra at once suggested the interpretation of this: the nebula consisted not of a cluster of stars but simply of a luminous gas. Other nebulae were examined; some showed similar spectra and others spectra generally resembling those of stars. It became clear that these objects, up to then regarded as identical in nature, belonged to two classes: some were clusters of stars, which would be seen as such with greater telescopic power, while others were uniformly gaseous. The bright lines observed in the gaseous nebulae, however, presented a puzzle. Hydrogen was readily identifiable, but there were other lines corresponding to nothing known on the earth; and a new element, provisionally called “nebulium,” was postulated. It was not until 1927 that it was discovered by Ira S. Bowen that nebulium was ionized oxygen and nitrogen.

Huggins followed up this work by spectroscopic observations of comets and of a nova, or new star, which appeared in the constellation Corona Borealis in 1866. He showed that the radiations of three comets gave spectra containing bands coincident in position with those obtainable from a candle flame in the laboratory, and concluded that they arose from carbon or its compounds. Huggins was more attracted by the fainter than by the brighter celestial objects and gave little attention to the sun. It was accordingly his younger contemporary Norman Lockyer who discovered how to make spectroscopic observations of the solar prominences in full sunlight. On hearing of this achievement, Huggins supplemented it by simply widening the slit of the spectroscope, thus revealing a prominence in its natural form, in the light of each element that it contained, instead of merely by a narrow spectrum line.

Another example of Huggins’ opportunism is afforded by his early perception of the possibility of applying the Doppler effect to the determination of the motions of the stars in the line of sight. It was in 1841 that the Austrian physicist Christian Doppler deduced on theoretical grounds that the motion of a source of sound or light—both regarded as wave phenomena—toward or away from an observer should cause a change in the frequency of reception of the waves, manifesting itself as a change of tone with sound and a change of color with light. He did not reach a full understanding of the effect of this change on stellar observations, for he thought that it would make a receding star appear redder, and an approaching star bluer, than if the star were stationary. In fact, since stellar spectra extend into the invisible regions of the infrared and the ultraviolet, all that radial motion could do would be to shift the whole visible spectrum slightly to one side or the other; its whole range of colors would still appear, leaving the resultant color unchanged. Fizeau later pointed out that, nevertheless, use could be made of the effect because the absorption lines in the spectra would partake of this general displacement; and the amount of their shift—measured by the difference of wave length of the stellar lines and the lines of the same substances produced from stationary sources in the laboratory—would indicate the velocity of the star along the line of sight, the so-called radial velocity.

Huggins at once perceived the possibility of applying the knowledge he had obtained of the laboratory spectra of elements to the determination of such velocities. He consulted Clerk Maxwell on the theory of the matter; and after various delays in securing a sufficiently powerful spectroscope he succeeded, in 1868, in obtaining a value for the radial velocity of Sirius of 29.4 miles a second away from the sun—a figure which later, with better instruments, he amended to between 18 and 22 miles a second. This is now known to be too large, although the direction is right; but it must be remembered that only visual observations were then possible and that the attainable accuracy of measurement fell short of that which we now regard as essential for this work. The principle had been established, however, of introducing into astronomy one of the most fruitful sources of knowledge we possess concerning the structure and evolution of the universe.

Although, as has been said, these observations were visual, Huggins had not overlooked the desirability of photographing stellar spectra; and as early as 1863 he attempted to photograph the spectrum of Sirius, the apparently brightest star in the sky. But the result was poor, and he realized that the time for this refinement had not come. Satisfactory results were not obtained until 1872, by Draper; and Huggins was not slow to follow them up by extensive photographic observations of the spectra of stars bright enough for this type of examination. He also sought to apply spectroscopic photography to the detection of the solar corona in full sunlight and at first thought he had succeeded, but this hope was not confirmed. Nevertheless, he devoted his Bakerian lecture to the Royal Society in 1885 to the subject “The Corona of the Sun.”

Pursuing his studies of the nebulae, Huggins came into conflict with Lockyer, another pioneer in spectroscopic astronomy. Lockyer had formed an imposing hypothesis of celestial evolution, known as the meteoritic hypothesis, a vital piece of evidence for which lay in the supposed identification of the “nebulium” green line with the head of a band, or fluting, observed in the spectrum of a magnesium spark in the laboratory. Not only was it doubtful whether, even under the admittedly unfavorable conditions of observation of nebular spectra, an extended band could appear so like a single sharp line, but also there was a slight discrepancy between the wavelength measurements of the radiations from the two sources. Huggins refused to admit their identity, and later knowledge has fully justified his skepticism.

A comparison of Huggins and Lockyer, so similar in time, place, and scientific objectives and so different in character, is inevitable. Each could serve as a type of his class—Lockyer as the adventurous and Huggins as the cautious investigator. To Lockyer, observational knowledge was merely a means to an end—the understanding of the whole course of nature. To Huggins it was an end in itself—ultimately to lead to understanding, of course, but, at the present, the beginning of a new and apparently limitless means of inquiry, to be gathered by patience and strict accuracy, uninfluenced by theoretical expectation or desire. His discovery of the gaseous nature of nebulae, which to many seemed to confirm William Herschel’s conjecture that these bodies might be the parents of stars, led him to point out that such a conclusion was not safely to be drawn, since the nebulae seemed to contain very few elements and the stars many. At that time the chemical elements were regarded as eternally unchangeable; and while Lockyer, by his “dissociation hypothesis,” simply brushed aside this obstacle, to Huggins it appeared insurmountable. As a contrast to Lockyer’s sweeping meteoritic hypothesis, which sought to comprehend the whole universe in time and space, the following summing up by Huggins of his life’s work, published in 1899 in the first of his two volumes on the work at his observatory, may be cited:

As the conclusion of the whole matter, though there may be no reason to assume that the proportions of the different kinds of chemical matter are strictly the same in all stars or that the roll of the chemical elements is equally complete in every star, the evidence appears to be strong that the principal types of star spectra should not be interpreted as produced by great original differences of chemical constitution, but rather as successive stages of evolutional progress, bringing about such altered conditions of density, temperature, and the mingling of the stellar gases, as are sufficient presumably to account for the spectral differences observed; even though with our present knowledge a complete explanation may not be forthcoming.

In retrospect a decision between these contrasting attitudes passes into insignificance beside the recognition that the contribution of each to later progress was essential and beyond the reach of the other.

BIBLIOGRAPHY

There is no full-scale biography of Huggins. His widow intended to write a personal sketch of his life but died, in 1915, before the work was completed. The material she had prepared, after some vicissitudes, was ultimately embodied in a small volume entitled A Sketch of the Life of Sir William Huggins, K.C.B., O.M., by C. E. Mills and C. F. Brooke, which was published privately (London, 1936). The authors write that “they have merely taken it upon themselves to edit the material at their disposal, and, having no knowledge of the mysteries of science, they have endeavoured as far as possible to steer clear of purely technical matters.” Obituary notices in the Dictionary of National Biography; Proceedings of the Royal Society, 86 (1911–1912); and Monthly Notices of the Royal Astronomical Society, 71 (1911), 261, recount the course of his scientific work.

Huggins contributed numerous original papers to learned soceities, those which he considered the more important being reprinted in Publications of Sir William Huggins’s Observatory, Sir William and Lady Huggins, eds., 2 vols.(Londond, 1899–1909). Vol. I, Atlas of Representative Stellar Spectra, contains a history of the observatory, a comprehensive list of published papers, a description of the instruments used and the methods of observation, and an account of the later work of the observatory that had not been previously published elsewhere. There are twelve large plates, mainly of stellar spectra. Vol. II, The Scientific Paper of Sir William Huggins contains reprints of published papers on the work done at the observatory from its foundation in 1856, classified under various headings and supplemented by reprints of Huggines’ more important lectures and addresses.

Huggins’s only other published book is a collection of his annual addresses as president of the Royal Society, The Royal Society, or Science in the State and in the Schools (London, 1906).

A short article contributed by him to The Nineteenth Century (June, 1897), entitled “The New Astronomy; a Personal Retrospect,” gives an interesting account of some of his work.

Herbert Dingle

Sir William Huggins

The English astronomer Sir William Huggins (1824-1910) pioneered in applying the techniques of spectrum analysis, or spectroscopy, to the study of the stars.

William Huggins was born in London on Feb. 7, 1824, to a family of considerable means. Educated by tutors and under no obligation to earn a living, he occupied his early years with the study of physics, chemistry, and physiology. Only in 1856 did his interests settle on astronomy, and upon building a private observatory during that same year at Tulse Hill, South London, he began making routine types of observations. Then, in 1859, Gustav Kirchhoff and Robert Bunsen published their epochal interpretation of spectral lines, according to which each of the chemical elements emits and absorbs light of various characteristic frequencies. Huggins became one of the small band of astronomers who utilized this discovery to forge a new branch of science—astrophysics.

Much of the early spectroscopy work concerned the sun, whose spectrum displayed numerous dark lines, the significance of which could scarcely be guessed. The analogous spectra of stars were so faint that little more could be done than group them into various types, in the hope (eventually fulfilled) that each type would correspond to a particular type of star, or even a particular phase in an evolutionary cycle of star development. Huggins, however, determined to perfect his instruments to the point of permitting some genuine analysis of stellar spectra. By 1863 he had succeeded to the extent of being able to name some of the chemical constituents of several stars on the basis of numerous stellar emission lines. Similar attempts on comets and planets were less successful, but those on the nebulae were nothing short of spectacular. For about a century these hazy spots of light had been cataloged by the thousands. As telescopes were improved, many nebulae had been resolved into millions of individual stars grouped into what are now termed other galaxies. Whether all nebulae could be so resolved, or whether some of them were something other than a collection of stars, was decided by Huggins in 1864, when he discovered, in the constellation Draco, a bright nebula whose spectrum clearly stamped it a mass of glowing gas.

Interesting as these early findings were, their very novelty militated against appreciation of the real significance of the new tool—spectroscopy. In 1868, however, Huggins established the truly revolutionary character of spectroscopy beyond all doubt. Celestial movements were what astronomers understood, and movements were what he gave them—movements of a kind unobtainable in any other way. By drawing an analogy to the shift of pitch that accompanies a moving source of sound waves (the Doppler effect), he inferred, by measuring a shift in its spectral lines, that the bright star Sirius was moving away from the sun at a rate of 29 miles per second.

Huggins worked until the day of his death, on May 12, 1910, following the lines of research opened in his first decade of spectroscopic inquiry and pioneering in the use of photography. In recognition of his contributions he was knighted (1897), awarded the Order of Merit (1902), and showered with honors from all parts of the scientific world.

Further Reading

The only biography of Huggins is John Montefiore and others, A Sketch of the Life of Sir William Huggins, K. C. B., O. M. (1936), from material collected by Lady Huggins. □