Chapter 2—Part 3

Eclecticism, Opportunism, and the Evolution
of a New Research Agenda:
William and Margaret Huggins and the
Origins of Astrophysics

Barbara J. Becker

A Dissertation submitted to The Johns Hopkins University
in conformity with the requirements for the degree of
Doctor of Philosophy
Baltimore, Maryland
1993

Copyright ©1993 by Barbara J. Becker
All rights reserved

CHAPTER 2—PART 3

UNLOCKING THE "UNKNOWN MYSTERY OF THE TRUE NATURE OF THE HEAVENLY BODIES"

Reception of Spectrum Analysis Applied to the Stars

When the full report of their work was submitted in 1864 for publication in the Philosophical Transactions, it was refereed by George Stokes.¹²² Stokes acclaimed it as a "model of patient and accurate investigation." As evidence of this, Stokes pointed to the fact that only two stars are considered in the paper in spite of the large number observed because the authors wished to insure the accuracy of their statements and so rejected any observations which presented any interpretive problems.

Shortly after the first preliminary report appeared in the Proceedings, J. Norman Lockyer, a newly elected Fellow of the RAS, and an amateur astronomer who would come to play a significant role in William Huggins' later career, wrote a brief description of it for the Monthly Notices.¹²³ Lockyer's enthusiastic note was followed a few pages later by a brief report submitted by George Airy on the spectral work being done at the Royal Observatory at Greenwich complete with drawings of the spectra of several stars (see Figure 15).¹²⁴ Despite these expressions of local enthusiasm for stellar spectroscopy, no mention of it was made in the "Progress of Astronomy" essay included in the Monthly Notices' annual "Report of the Council" for 1864.¹²⁵ This, as we shall see, was soon to change.¹²⁶

In the meantime, as mentioned earlier, it was in the pages of the Astronomical Register where reference to Huggins' initial spectral work with Miller was to be found.¹²⁷ In addition, the Register's editor directed readers' attention to a recent lecture on spectrum analysis given by William Allen Miller at the Royal Institution,¹²⁸ as well as to recent articles by other observers engaged in spectroscopic investigations published in both Chemical News and Astronomische Nachrichten.¹²⁹ This same journal printed an abbreviated transcription of the RAS meeting of 10 April 1863, at which the Astronomer Royal, George Airy, then President of the RAS, presented an oral report of work on stellar spectra being pursued at Greenwich.¹³⁰ An account of this report along with illustrations is also given in the Monthly Notices.¹³¹ The report in the Astronomical Register includes some of the discussion which followed Airy's presentation. Admiral Manners, presiding in Airy's stead, expressed the Society's thanks for the Astronomer Royal's report:

Although many private observers were giving attention to the subject, it was to Greenwich Observatory that all looked as a directing star: nothing could escape it -- in fact it seized on anything that was in the remotest way connected with Astronomy.¹³²

These fawning remarks are indicative of the decorum of public discourse and of the respect accorded Airy by virtue of his age and station. They contrast vividly with the rather direct and critical comments put forward by Huggins during the discussion which followed. It is true that at this early stage of the Astronomical Register's existence, reports from the meetings tended to concentrate on what H. F. Newall later characterized as "pithy remarks."¹³³ Nevertheless, the portion of Huggins' remarks which was reported in the Astronomical Register reveals an assertive side of Huggins normally hidden in published accounts and thus is worth printing in full:

Mr. Huggins who had recently, in association with Professor W. A. Miller, read a paper at the Royal Society on this subject, wished to ask whether the lines shewn in the diagram were the whole of the lines seen. He considered his method of observation was calculated to give more perfect results than that employed at Greenwich. The Spectrum of Capella, for instance, which in the Astronomer Royal's drawing has only two bars, he had observed to be full of fine lines, so fine and so many as apparently to defy accurate delineation. This Star, as well as several others, seems to exhibit quite as many lines as would be seen in the Solar Spectrum under similar circumstances of diminished light and of dispersive power. It, as well as Aldebaran and Arcturus, possesses the "D" line and altogether resembles the Sun very closely. Sirius in addition to the three bars, has lines corresponding with B and C, and indications of other lines between. Mr. Huggins remarked on the extreme importance of obtaining the exact position of the lines relatively to those in the Solar Spectrum, and stated that his measures were taken by a direct comparison with a Sodium line thrown into the apparatus, and viewed with the Stellar Spectrum. Mr. Huggins had also compared directly the Spectra of other metals with the Star Spectra. As a supplement to eye-observations and in the hope of obtaining some information of the relative temperatures of the Stars, he had succeeded in photographing the more refrangible portion of the Spectra of Sirius and Capella, Professor W. A. Miller having found that the invisible Spectrum has a connection with the temperature of the source of light¹³⁴

Charles Pritchard was apparently the first to speak following Huggins' bold remarks. He pressed Huggins on the reliability of Huggins' own observations. Only after Huggins' confident answer to this question did his earlier comments draw a response from Greenwich. Airy delegated "Mr. Carpenter, the actual observer of the Spectra at Greenwich" to respond. James Carpenter, who had initiated this spectral research project (see Figure 16b), explained that while many lines had been observed, "only those measured were introduced into the diagram."¹³⁵ Given this exchange, it is perhaps easier to understand why, despite Airy's initial enthusiasm in announcing the results of Greenwich's first spectroscopic investigations, they were discontinued for nearly a decade.¹³⁶

Spectra of Terrestrial Elements

Huggins' collaboration with Miller, a chemist with a long-term professional interest in the qualitative spectroscopic analysis of terrestrial substances, alerted him to the lack of precise spectral maps of terrestrial metals. Such maps would be crucial for identifying the presence of known terrestrial elements in stellar spectra using visual comparisons. To rectify this problem, Huggins embarked on an extensive series of his own observations of metallic spectra in 1863.

The notebook records of these experiments are the only ones from that early phase of Huggins' spectral work that survive. As mentioned earlier, these records were kept in a notebook separate from that consigned to the observatory.¹³⁷ However, even this record is incomplete and includes only values obtained from a handful of the 25 metals Huggins named in the published paper.¹³⁸ Because Huggins' prisms were made of glass, which is opaque to ultraviolet radiation, he would have been confined to viewing the visible spectrum, the segment of the spectrum of greatest interest to most astronomical observers at the time. Nineteen of the metals he examined were identical to those whose ultraviolet spectra Miller had recently photographed.¹³⁹ Huggins noted the assistance received from Miller and others in obtaining pure samples of the various metals, and Miller communicated the paper to the Royal Society.

One referee of Huggins' paper on terrestrial spectra was the Reverend Thomas Romney Robinson (1792-1882). Robinson, the director of the Armagh Observatory in Ireland since 1835, had been elected to Fellowship in the Royal Astronomical Society when Huggins was just a boy of six.¹⁴⁰ Always an avid investigator of new phenomena, Robinson had recently engaged in his own spectroscopic studies and was thus no stranger to the practical challenges which faced the observer.¹⁴¹ Robinson was particularly impressed with Huggins' plan for standardizing spectral maps using a graduated circle about which the viewing telescope could be moved and aligned with individual spectral lines using finely calibrated micrometer screws. He viewed this as an improvement over what he referred to as Kirchhoff's "detached scale" design in which by means of reflection, the image of a comparative scale was superimposed upon the spectral pattern as seen through the observing telescope. In fact, this "detached scale" design was Bunsen's and was used principally in the laboratory for examination of terrestrial spectra. Kirchhoff had used a design initially developed by Steinheil to map the solar spectrum. This design was quite similar to the one by John Gassiot which Huggins used to carry out his observations.¹⁴² Robinson may have been unfamiliar with Kirchhoff's apparatus.

Robinson did make one other interesting point. He argued that Kirchhoff's measures were so arbitrary that it made comparison of spectra difficult. Perhaps "arbitrary" was not the right word, here. Kirchhoff's measures were peculiar to his own apparatus. Others had to adjust their apparatus, or scales to match his. Dispersion is a non-linear property and every material has its own dispersion rate. Even with the same apparatus, local variations in environmental factors like temperature and humidity can introduce notable discrepancies in the apparent location of spectral lines from one trial to the next. Agreement among observers was not a simple matter.¹⁴³

Robinson drew attention to the fact that Huggins chose to align his prism train using the angles of minimum dispersion of the two sodium D lines in place of the green F line used by Bunsen, thus making the spacing between the D lines a standard of comparison. This choice, Robinson argued, would assist in calibrating measures made by different observers using different instruments. Robinson also noted that Huggins' use of six prisms and a fine telescope resulted in a remarkable increase in precision.

There is a less conspicuous, but no less significant contribution here that stems from Huggins' lack of interest in studying the solar spectrum coupled with his need to find a way to standardize work done on celestial objects visible only after the sun has gone below the horizon. Huggins chose to compare the chemical spectra he observed against the spectrum attributed to air produced by generating a spark between two platinum electrodes. In this way, comparisons could be made at any time of the day, free of the need to track the sun or await its appearance. This also had the effect of moving the mensurational focus of spectral work away from that provided by Kirchhoff to a new standard, a welcome shift in method for those British investigators who believed they had been forestalled by Kirchhoff in 1860.

The Riddle of the Nebulae

In this section, I shall turn to Huggins' observations of nebular spectra. Nebulae are, as a class, among the faintest objects on the sky. That Huggins opted to test the analytic power of the spectroscope on a variety of celestial objects rather than pursue a concentrated survey of stellar spectra was in keeping with the somewhat eclectic and opportunistic bent of his earlier research style as described in chapter 1. Whatever encouraged Huggins to subject the light of nebulae to spectroscopic scrutiny, it was a bold stroke which ultimately propelled him to a position of prestige and authority within the wider community.

Sarah F. Whiting, Professor of Astronomy at Wellesley College and the first to examine Huggins' observatory notebooks, made the tantalizing suggestion that the notebooks contained the record of his early observations of nebular spectra. "In 1864," wrote Whiting, "[Huggins] records his observations of the green lines in the nebulae, and scores of nights were spent trying to match these lines with magnesium, lead, iron, what-not."¹⁴⁴ Entries fitting Whiting's description can be found in Huggins' first observatory notebook. However, they are clearly dated 1889 and 1890, and they are written in Margaret Huggins' hand.¹⁴⁵ These details should have caught Whiting's attention. Her confusion may have arisen from a combination of wishful thinking and the fact that these entries follow the few made by William Huggins in the mid-1860s which have already been described.

In fact, there is nothing in his notebooks, correspondence or published papers to bridge Huggins' abrupt shift in attention from common terrestrial elements to the unresolved nebulae. Huggins simply tells us in his retrospective essay, "I was fortunate in the early autumn of the ... year, 1864, to begin some observations in a region hitherto unexplored ..." namely, the nebulae.¹⁴⁶ Huggins could indeed feel "fortunate" to have turned his spectroscope on nebulae, for, as I shall argue in this section, it was Huggins' announcement of the results of his investigation of nebular spectra which captured the imagination of his amateur astronomer colleagues and heightened their awareness of the potential of prismatic analysis to generate new knowledge.

Nebulae had been examined before by skilled observers with far superior telescopic instruments than those Huggins possessed, but in the early 1860s many questions remained unanswered concerning the physical nature of these celestial objects.¹⁴⁷ Shortly after the turn of the nineteenth century, the great William Herschel had compiled an extensive series of catalogues of nebulous objects visible in the Northern hemisphere.¹⁴⁸ He used the morphological differences he had identified in these many objects to define a set of distinctive categories which he then connected in temporal sequence by a central organizing power, namely gravitational attraction.¹⁴⁹ Reports of notable changes in the shape, size and/or brightness of individual nebulae encouraged the belief that the laws controlling the movement of the material comprising the nebulae could be described and ultimately understood.¹⁵⁰ But the resolution of some nebulae into star clusters by subsequent observers using larger telescopes than Herschel's raised the question of whether his so-called "shining fluid" -- a sort of celestial humus which nourished the natural cycle of growth and decay in the heavens -- was merely a chimera generated by the inadequate resolving power of available instruments.¹⁵¹

In 1850, William Parsons, the third earl of Rosse (1800-1867), an Irish nobleman who had earned a reputation for building exceptionally fine large telescopes, cautiously suggested that luminous regions yet unresolved might yield to larger and more perfect instruments. However, after an exhaustive examination of numerous nebulae with his unparalleled six-foot reflector, he despaired that, "as observations have accumulated the subject has become, to my mind at least, more mysterious and more inapproachable." He concluded that "when certain phenomena can only be seen with great difficulty, the eye may imperceptibly be in some degree influenced by the mind" causing reports to conform to the observer's own predispositions.¹⁵² Given the real physical limits of instrumentation and atmospheric distortion, it seemed to Lord Rosse that the "riddle of the nebulae" would remain, for the time being at least, unanswerable in any positive, testable way.¹⁵³

The rich ambiguity of these telescopic observations fuelled a fertile tension which grew out of speculations on the origins of the solar system presented by Pierre Simon de Laplace (1749-1827) in his popular Système du Monde.¹⁵⁴ While Laplace treated the question of celestial dynamics on the local level, that is, accounting in a natural and purely secular way for observed motions of the sun and its retinue of planets, later enthusiasts extended its application to the more universal problem of stellar formation and development as part of the search for a unified theory of gradual and progressive development of all natural phenomena from chaos to order.¹⁵⁵ Simon Schaffer has recently argued that the debate over the nebular hypothesis which arose in Britain in the first half of the nineteenth century served as a platform from which "Victorians worked out their differing views of the progress of their world."¹⁵⁶ In light of Schaffer's remarks, it is tempting and not entirely ingenuous to see Huggins' own self-centered sense of personal gain in the early 1860s reflected in his rather confident speculation that, in fact, nebulae may be embryonic stars: brilliant careers, like brilliant suns, can have fuzzy, even amorphous beginnings. The stuff is there waiting to take shape.¹⁵⁷

Before Huggins began his observations of nebular spectra, he and Miller, in their joint paper on stellar spectra, made a strong case for a "unity of plan" throughout the universe encompassing the substance, structure, and dynamics of organic and inorganic matter.¹⁵⁸ In his first paper on the spectra of nebulae in 1864, Huggins stated that his interest in attempting the difficult task of subjecting the extremely faint light of nebulae to prismatic analysis stemmed from the growing suspicion that celestial objects shared spectral similarities which permitted conclusions to be drawn concerning their chemical and physical make up. "It became, therefore, an object of great importance," he said, "to ascertain whether this similarity of plan observable among the stars and uniting them with our sun into one great group, extended to the distinct and remarkable class of bodies known as nebulae." What needed to be determined, and what Huggins hoped would be revealed by the spectroscope, was the "essential physical distinction" which "separates the nebulae from the stars."¹⁵⁹ In other words, Huggins expected nebulae to differ from stars not so much in terms of the stuff from which they were made as in their temperature or density. If nebulae were distant, irresolvable clusters of stars, their spectra should be star-like, that is, a faint continuous background of color interrupted by recognizable patterns of absorption lines. If, on the other hand, nebulae were indeed gaseous stellar embryos, an observer would still see the familiar and characteristic spectral signatures of the many elements known to exist in the sun and other stars. Instead of dark absorption lines common to ordinary star spectra, however, bright-line emission spectra, like those produced by flames or electric sparks, would be observed.

Though he would have vehemently denied it, Huggins, like all observers, was prone to suggestion. What he was looking for informed his observational interpretations. Some observers, like William Herschel, saw the symbiosis of expectation and observation as a training for the eye which when properly balanced could make one a truly great observer.¹⁶⁰ Lord Rosse, as we have seen, worried that a predisposed eye could lead one to erroneous conclusions especially when the object under scrutiny is just at the edge of perception.¹⁶¹ Huggins believed his observations were bias-free because he selectively rejected what he considered substandard measurements or qualitative descriptions and was able to adapt to unanticipated findings. He would not have agreed that such behavior was predicated upon an internalized set of expectations. Knowing what Huggins expected to see before he began his spectroscopic examination of nebulae provides the context for interpreting his reported observations and for understanding his own reaction to them.

As his first object to scrutinize, Huggins selected a member of the class of nebulae William Herschel had dubbed "planetary" by virtue of their characteristic disk-like appearance in the telescope.¹⁶² The particular planetary nebula chosen is one of the brighter and more colorful of the planetaries, one described by some as bluish, by others as bluish-green.¹⁶³ In his 1897 retrospective account, Huggins wrote:

On the evening of August 29, 1864, I directed the telescope for the first time to a planetary nebula in Draco. The reader may now be able to picture to himself to some extent the feeling of excited suspense, mingled with a degree of awe, with which, after a few moments of hesitation, I put my eye to the spectroscope. Was I not about to look into a secret place of creation?¹⁶⁴

Carrying the wide-eyed reader along in this suspenseful and well-crafted narrative, Huggins continued:

I looked into the spectroscope. No spectrum such as I expected! A single bright line only! At first I suspected some displacement of the prism, and that I was looking at a reflection of the illuminated slit from one of its faces. This thought was scarcely more than momentary; then the true interpretation flashed upon me. The light of the nebula was monochromatic, and so, unlike any other light I had as yet subjected to prismatic examination, could not be extended out to form a complete spectrum....

The riddle of the nebulae was solved. The answer, which had come to us in the light itself, read: Not an aggregation of stars, but a luminous gas.¹⁶⁵

There can be no question that what Huggins observed in his spectroscope during his initial examination of the nebular spectrum was not what he expected to see. However, I would argue that Huggins was not so much surprised because the spectrum of this planetary nebula was comprised of emission lines, but rather because of its near monochromatic character. The spectra of other planetaries he examined shortly after shared this remarkable appearance. Huggins, who had hailed the similarity between stellar, solar and terrestrial spectra as evidence for a fundamental uniformity of nature in his paper on stellar spectra was now forced to conclude that some nebulae were "systems possessing a structure, and a purpose in relation to the universe, altogether distinct and of another order from the great group of cosmical bodies to which our sun and the fixed stars belong."¹⁶⁶

In his retrospective account, Huggins minimized his initial concern that this unexpected result was in some way erroneous, perhaps stemming from instrumental difficulties. He did not treat it quite so lightly in his Philosophical Transactions paper. Bands of light flashing into view by virtue of prismatic internal reflection could easily mislead the observer and it was prudent to be wary when unexpected lines appeared.¹⁶⁷

It is unfortunate that the notebook account of this work, if it still exists, has not been uncovered. As we shall see in the next chapter, his more complete record of his work on the measurement of motion in the line of sight permits a glimpse at how Huggins confronted and resolved observational obstacles and mensurational inconsistencies in contrast with how he chose to represent these difficulties in print. In this case, however, we can only assume that Huggins' published description of his work on nebular spectra conformed to the accepted prescription for scientific papers at the time, thus difficulties are abstracted and placed within an artificially ordered pattern of unfolding discovery. The difficulties, then, represent a sequence of tests imposed on the would-be discoverer by Nature's unwillingness to reveal its secrets to any but the worthy. The problems solved constitute the problems faced. But without the notebook record, we cannot know how these problems were dealt with.

Two letters which Huggins wrote to J. Norman Lockyer during 1864 supplement the notebook record and provide the only unpublished reference to his spectroscopic work during that period. It is important to keep in mind that Lockyer and Huggins had a long and complex relationship ranging from open and friendly camaraderie to spiteful and rancorous contention. These two letters were composed during the early amicable stage of their acquaintance when their astronomical interests did not overlap. At the time, Lockyer was editing articles on scientific subjects and reporting the activities of the Royal Society for the journal, Reader. In that role, Lockyer was perceived by Huggins as an ally with valuable connections to the popular press. Positive commentary by Lockyer on Huggins' work would underscore its importance, enhance Huggins' visibility, and extend his renown outside the astronomical community.

In 1864, Lockyer was a relative newcomer to the RAS, having been elected to fellowship just two years earlier. He was actively studying the moon and the planet Mars. Until that date, Lockyer had expressed no interest in pursuing spectroscopy himself.¹⁶⁸ Huggins' 1864 letters were written, then, to Lockyer, the science editor, not to a fellow spectroscopist. Awareness of that fact alerts the historian to the letters' dual purpose: While ostensibly they served to convey pertinent information to Lockyer as a man of science, the letters were also meant to cajole and impress him as a potential proselytizer.¹⁶⁹

Just one month after his first nebular observation, Huggins wrote to Lockyer to boast that the Royal Society had accepted a paper on his own independent observations of nebular spectra "in my name only" which, because of what Society Secretary George Stokes had called its "interest & importance," was to be printed "at once." "Perhaps," Huggins concluded, "you may be inclined to write an article [in the Reader] on the nebulae when you see my paper, which contains some interesting observations & deductions."¹⁷⁰

Huggins clearly appreciated that the exposure attained by publishing in the journals of the Royal Society accorded him no small degree of prestige in a group whose recognition he valued and of which he yearned to be a part. By the early 1860s, the Royal Society had regained much of the prestige it had gradually lost during the eighteenth and the first half of the nineteenth centuries when Fellowship was accorded to increasingly larger numbers of non-scientific men at the expense of the aims its originators had intended.¹⁷¹ Limitations imposed in 1846 on the election of new Fellows effectively reduced the numbers of Fellows and increased the proportion of individuals with serious scientific interests relative to dilettantes.¹⁷² As only fifteen new Fellows could be elected each year, the Society was able to be more selective. The competitive nature of its election process made Fellowship in the Royal Society a goal that was just beyond the reach of many aspirants and hence all the more tantalizing a prize.

Huggins' paper represented something very new in nebular study. Edward Sabine, President of the Royal Society, exulted, "[H]ere we have a totally different view opened."¹⁷³ This was welcome news for those like Sabine, who saw the question of the nature of nebulae as a crisis for observational astronomy. In fact, "crisis" is the very word he used to describe the impasse that had been reached on the matter due to the fact that even the largest telescopes then built were unable to resolve many of the nebulae on the sky. In Sabine's view, Huggins' ability to breach this impasse was due to his "referring the spectra lines to no mere instrumental scale ... but to standard spectra of known elements which are formed in juxtaposition with that to be examined, and to which its lines can be compared with extreme precision."¹⁷⁴

What set Huggins' observations apart from those of his predecessors was the confident sense he conveyed in his first paper on nebular spectra that his particular spectroscopic apparatus and method constituted an entirely new and reliable means for attacking the problem of the nebulae. The evolution of the ingenious design of Huggins' apparatus warrants further study. It introduced a sequence of mirrors which directed the light from the comparison source into the collimating tube thus permitting the observer to see and compare simultaneously the spectrum of the celestial body under scrutiny and that of a known terrestrial substance (see Figure 18). He may have developed it in response to difficulties he experienced in the course of his work on terrestrial spectra.¹⁷⁵

Figure 18. William Huggins' direct comparison spectroscope (from Schellen, 465 and 469), with enlargement showing comparison prism fixed on the slit [from J. Norman Lockyer, Stargazing: Past and Present (MacMillan & Co.: London, 1878): 423].

Huggins' colleagues in the RAS commended not only his instrumental design, but also his shrewd application of a new method to an old problem. Much of their enthusiasm can be traced to Warren De La Rue, whose Presidential Address to the RAS in November 1864, gave voice to the subtle spirit of change afoot within the Society's ranks. Decrying those who would retain old methods for tradition's sake, De La Rue exhorted his Fellows:

Let us not indulge in vain regrets for superseded methods; but, on the contrary, let us reflect how rich in promise is its future, if, in rejecting all idea of finality in any of its methods or procedures, we gladly adopt the best aids which the progress of physical inquiry places within our reach; and in this, as in all our contests for new scientific territory, admit no rallying-cry but -- Forward!¹⁷⁶

De La Rue, it will be remembered, was a pioneer himself in the application of photography to astronomy. He had been President of the Chemical Society and chaired the meeting when Roscoe introduced the method of spectrum analysis to that body in 1861. It was certainly auspicious that at the time Huggins presented the startling results of his observations, someone like De La Rue who was well-acquainted with the potential power of the method of spectrum analysis for resolving questions concerning the physical and chemical constitution of celestial bodies was serving as President of the RAS. In this capacity, De La Rue helped shape the positive response of the RAS to Huggins' work. The Astronomical Register praised Huggins' new research on nebulae "the fruits of which are of the most interesting character, and tend to prove conclusively that the constitution of some at least is truly gaseous or vaporous, and that the generalisation of considering all these bodies as clusters of stars must be given up."¹⁷⁷ Similarly, the "Progress of Astronomy" section of the annual "Report of the Council" for 1865 announced:

... the relation between terrestrial physics and the physics of the sidereal heavens is rapidly becoming more intimate, the boundary line once supposed to divide them is gradually disappearing, while new and unexpected fields open for the application of results of experimental philosophy, in distant regions of space, where formerly they were supposed to have little or no concern.¹⁷⁸

This report expanded on De La Rue's earlier remarks and lauded the publication of both John Herschel's monumental "Catalogue of Nebulae and Clusters of Stars" and Huggins' work on nebular spectra, which, it was asserted, provided the "first glimpse of our knowledge of the constitution of the mysterious systems of matter which have formed the [nebulae]."¹⁷⁹

At the same time, Huggins received considerable acclaim from within the ranks of the Royal Society. We have already seen that the President of the Royal Society, Edward Sabine, identified Huggins' spectral work on the nebulae as one of the most important contributions to astronomical research in 1864 and expressed hope that Huggins would continue his spectral exploration of the nebulae with "even higher instrumental powers."¹⁸⁰ In June 1865, Huggins was elected to Fellowship in the Royal Society, an event which marked a major turning point in his career. Less than a year later, he began recording spectroscopic observations of celestial bodies in a new notebook.¹⁸¹ The first entry in this notebook, dated 14 March 1866, described his observation of three distinct lines in a nebula in Hydra. Most entries which followed were of a very different character than those made in the first notebook. Although he still recorded routine observations of planets and eclipses, Huggins clearly had become much more interested in applying the spectroscope to a wide variety of celestial objects.

We have seen in this chapter that by early 1862, a wide range of British men of science were aware of Gustav Kirchhoff's claim to have discovered a physical explanation for the so-called fixed lines in the solar spectrum. While this news was greeted with skepticism by some, a few chemists and physical scientists in Britain were already expressing cautious optimism concerning the promise prismatic analysis held for generating new knowledge of the stars and other celestial bodies. William Huggins was introduced to the potential application of this method to astronomical research at a point in his life when he had not yet found an investigative focus to channel his own evolving interests. As an independent observer operating on the periphery of the British astronomical community, Huggins was free to devote time to those projects which attracted his attention, to the exotic rather than the mundane. His was an opportunistic and eclectic research agenda which rewarded flexibility, alacrity and openness in place of diligence, tenacity and servitude, the traditional values governing the work of contemporary institution-bound observers.

Huggins' seemingly meteoric rise to prominence as a serious amateur astronomer was the result of a conscious career strategy pursued on a number of fronts by a bright and ambitious man. It was also contemporaneous with the growth of interest in subjecting the light emitted by a variety of celestial bodies to prismatic analysis by an admittedly eclectic group of independent and self-directed observers in the international astronomical community.

To attain recognition and prestige from his Fellows, Huggins had to demonstrate both a commitment and a willingness to conform to the RAS's pre-existing performance standards. We saw in chapter 1 that Huggins had begun to move in this direction long before beginning his spectroscopic investigations by constructing an observatory building attached to his home, purchasing a high quality refracting telescope with which to make his observations, and contributing reports from his observatory for publication in the Royal Astronomical Society's Monthly Notices. But Huggins' documented actions during the early 1860s show that he wished to move from the periphery into the inner circle of serious amateur astronomy. To do that, Huggins had to convince those within that circle of the value and importance of prismatic analysis to the increase of astronomical knowledge and of his own technical competence in this area.

In this chapter, we saw that as Huggins subjected more terrestrial and celestial objects to spectroscopic scrutiny, he worked to sustain his growth in visibility and renown among his fellow amateur astronomers by confidently and rightly advertising his instruments, methods and resulting observations as clearly superior to any others engaged in similar tasks. He also strove to build on the potentially fleeting notoriety he achieved in the wider scientific community stemming from his collaborative work with William Allen Miller, the well-respected chemist, recognized pioneer spectroscopist and high-ranking official in the Royal Society. Huggins wisely nurtured this relationship which ultimately offered him not only a leg up into that elite scientific circle, but, as we shall see in the next chapter, increased opportunities for personal recognition and advancement.

NOTES
[click on footnote number to return to text]

122. George Stokes, "On Spectra of Fixed Stars by Huggins & Miller," RR.6.147, Royal Society Library.

123. [J. Norman Lockyer], "On the Spectra of some Fixed Stars," Monthly Notices of the Royal Astronomical Society 23 (1863): 179-80.

124. [George Biddell Airy], "Astronomer Royal, Apparatus for the Observation of the Spectra of Stars," Monthly Notices of the Royal Astronomical Society 23 (1863): 188-91.

125. "The Progress of Astronomy during the past Year," Monthly Notices of the Royal Astronomical Society 24 (1864): 102-7.

126. Warren De La Rue, "The President's Address," Monthly Notices of the Royal Astronomical Society 25 (1864): 1-17.

127. This report had been published earlier in the Reader, a journal with which Lockyer was closely associated and which aimed at encouraging what Meadows has characterized as "free and uninhibited discussion of contemporary controversial topics in science, religion and the arts." A. J. Meadows, Science and Controversy: A Biography of Sir Norman Lockyer (MIT Press: Cambridge, 1972): 16.

128. William Allen Miller, "On the Photographic Transparency of Bodies, and on the Photographic Spectra of the Elementary Bodies," lecture given 6 March 1863, Proceedings of the Royal Institution 4 (1863): 42-9.

129. In April 1863, this new periodical reprinted a brief, but glowing report on Huggins' and Miller's paper on stellar spectra which had been read to the Royal Society in February. Astronomical Register 1 (1863): 54.

130. Astronomical Register 1 (1863): 68-70.

131. Airy, "Apparatus for the Observation of the Spectra of Stars," Monthly Notices of the Royal Astronomical Society 23 (1863): 188-91. A brief announcement concerning the completion of an apparatus necessary for the prosecution of this work was included in the "Progress of Astronomy" section of the annual "Report of the Council," Monthly Notices of the Royal Astronomical Society 23 (1863): 143-4.

132. Astronomical Register 1 (1863): 70.

133. Newall, "Decade," in Dreyer, Turner, et al., 134.

134. Astronomical Register 1 (1863): 70.

135. Newall, "Decade," in Dreyer, Turner, et al., 152.

136. Airy was publicly and loudly criticized in 1872 for not having included stellar spectroscopy in Greenwich's research agenda. As we shall see in Chapter 5, Airy argued with some conviction that this was less a case of neglect than that spectroscopic study of celestial bodies neither conformed to his understanding of Greenwich's purpose and mission, nor did it fit into the daily routine there. No mention was made at that time of Carpenter's 1862-1863 spectroscopic efforts or of Huggins' blunt criticism of them.

137. These notes can be found in Notebook 4.

138. The other metals examined by Huggins were: sodium, potassium, calcium, barium, strontium, thallium, silver, tellurium, tin, iron, cadmium, antimony, bismuth, mercury, arsenic, lead, zinc, chromium, palladium, platinum, and lithium. The notebooks have data for iridium and he mentions having obtained a sample from Messrs. Johnson and Matthey, but there is no discussion of these measures in either the text or the table provided in the paper. He also mentions having received a sample of rhodium and nickel, but there is no record of measures obtained from observations he may have made of the spectra of these elements. Also, the text provides measures for the spectrum of lithium, but lithium is not included in the table. The text ends with the statement, "Several other spectra have been measured, or are in progress; these are reserved until the remaining metals and elements, as far as may be practicable, have been investigated." See Huggins and Miller, "On the Spectra of some of the Chemical Elements," Proceedings of the Royal Society 13 (1863): 43-4; idem., Philosophical Transactions 154 (1864): 139-60; idem., Philosophical Magazine Fourth Series, 27 (1863): 541-2.

139. Miller had not examined the spectrum of lithium, osmium, iridium, thallium, strontium, barium or calcium. Huggins did not examine the spectrum of tungsten, molybdenum, nickel, copper, aluminum, magnesium, or graphite/gas-coke.

140. Thomas Romney Robinson, "On the spectra of some of the Chemical Elements by William Huggins," RR.5.122, Royal Society Library.

141. See, Thomas Romney Robinson, "On Spectra of Electric Light, as modified by the Nature of the Electrodes and the Media of Discharge," Philosophical Transactions 152 (1862): 939-86.

142. For a description of Gassiot's design, see John P. Gassiot, "On Spectrum Analysis; with a Description of a large Spectroscope having nine Prisms, and Achromatic Telescopes of two-feet focal power," Proceedings of the Royal Society 12 (1863): 536-8.

143. In fact, the first map of the so-called normal solar spectrum -- a spectrum generated using diffraction rather than dispersion and, hence, free of dispersive variation -- was not published until 1869 by A. J. Ångström. See, A. J. Ångström, Recherches sur le Spectre Solaire (W. Schiltz: Upsala, 1868); idem., Spectre Normal du Soleil (Berlin, 1869).

144. Sarah F. Whiting, "The Tulse Hill Observatory Diaries," Popular Astronomy 25 (1917): 158-63; 160.

145. The entries made by Margaret Huggins in the back of Notebook 1, are a direct continuation of those found in Notebook 2. It seems that the Hugginses were not ones to let good paper go to waste.

146. Huggins, "The New Astronomy," 915.

147. See, Grant, History of Physical Astronomy, 563-78.

148. William Herschel's catalogues were published in the Philosophical Transactions. See his "Catalogue of One Thousand New Nebulae and Clusters of Stars," 76 (1786): 457-99; "Catalogue of a second Thousand of new Nebulae and Clusters of Stars; with a few introductory Remarks on the Construction of the Heavens," 79 (1789): 212-55; and, "Catalogue of 500 new Nebulae," 92 (1802): 477-528. See also, Michael A. Hoskin, William Herschel and the Construction of the Heavens (W. W. Norton & Co.: New York, 1963).

149. As early as 1791, Herschel suggested that stars might undergo a cyclical regeneration in a paper entitled "On Nebulous Stars, properly so called," Philosophical Transactions 131 (1791): 71-88. Twenty years later, he put forth his views on the temporal sequence of nebulous objects in "Astronomical Observations relating to the Construction of the Heavens," Philosophical Transactions 101 (1811): 269-336. See also, Simon Schaffer, "'The Great Laboratories of the Universe': William Herschel on Matter Theory and Planetary Life," Journal for the History of Astronomy 11 (1980): 81-111; and idem., "Herschel in Bedlam: Natural History and Stellar Astronomy," British Journal for the History of Science 13 (1980): 211-39.

150. Astronomer Royal, George Airy, eloquently expressed the optimism felt by celestial mechanicians like himself at the news that nebulae had been known to fluctuate in observable and possibly measurable ways. See, "President's Address," Monthly Notices of the Royal Astronomical Society 3 (1836): 167-74.

151. Lord Rosse, "Observations on the Nebulae," originally published in the Philosophical Transactions 140 (1850): 499-514; reprinted in The Scientific Papers of William Parsons Third Earl of Rosse 1800-1867 (P. Lund & Humphries & Co.: London, 1926): 109-24.

152. Lord Rosse, "Observations on the Nebulae," in Scientific Papers of William Parsons, 113-4.

153. See Grant, History of Physical Astronomy, 569-71. Jonathan Crary has recently drawn attention to the interaction between the human visual response and the prepared mind by reminding us of the fact that the Latin root for the word "observer," observare, "means 'to conform one's action to comply with,' as in observing rules, codes, regulations, and practices." In Crary's view, "There never was or will be a self-present beholder to whom a world is transparently evident. Instead there are more or less powerful arrangements of forces out of which the capacities of an observer are possible." Jonathan Crary, Techniques of the Observer: On Vision and Modernity in the Nineteenth Century (MIT Press: Cambridge, 1990): 6. For examples of this taken from the history of astronomy, see Norriss S. Hetherington, Science and Objectivity: Episodes in the History of Astronomy (Iowa State University Press: Ames, 1988).

154. Pierre Simon de Laplace, Exposition du système du monde, 2 vols. (Cercle Social: Paris, 1796) 2: 293-312.

155. Simon Schaffer, "The Nebular Hypothesis and the Science of Progress," in History, Humanity and Evolution: Essays for John C. Greene, James R. Moore, ed. (Cambridge University Press: Cambridge, 1989): 131-64; Silvan S. Schweber, "Auguste Comte and the Nebular Hypothesis," in In the Presence of the Past: Essays in Honor of Frank Manuel, Richard T. Bienvenu and Mordechai Feingold, eds. (Kluwer Academic Publishers: Dordrecht, 1991): 131-91. See also, John Pringle Nichol, Views of the Architecture of the Heavens (William Tait: Edinburgh, 1837); Robert Chambers, Vestiges of the Natural History of Creation (John Churchill: London, 1844).

156. Schaffer, "The Nebular Hypothesis," 131-2.

157. In his 1897 retrospective, Huggins claimed to have read and accepted Herbert Spencer's belief in the power of progress to guide the affairs of nature and man, but there are no contemporary documents to confirm this claim. See Huggins, "The New Astronomy," 916; Herbert Spencer, "Recent Astronomy and the Nebular Hypothesis," Westminster Review 70 (1858): 185-225.

158. Huggins and Miller, "On the Spectra of Some of the Fixed Stars," Philosophical Transactions 154 (1864): 413-35; 433-4.

159. Huggins, "On the Spectra of some of the Nebulae," Philosophical Transactions 154 (1864): 437-44; 437. Emphasis added.

160. Schaffer, "Herschel in Bedlam," 216.

161. Lord Rosse, "Observations on the Nebulae," in Scientific Papers of William Parsons, 113-4.

162. In retrospect, it was significant that Huggins selected this class of objects to begin his work instead of, say, the spiral nebulae, or a bright nebula like M42, the Great Nebula in Orion. The planetary nebulae present emission spectra which are strikingly different from stellar spectra or the continuous spectra of galaxies. The lack of ambiguity in Huggins' initial observations of planetary nebulae lent an air of confidence to subsequent work on a broader range of nebular types which presented observers with less clearcut results.

163. Burnham, 2, 870-2, with photograph. I would suggest that the colorful appearance of the planetaries drew Huggins to examine them spectroscopically before any of the other classes of nebulae.

164. Huggins, "The New Astronomy," 915-6.

165. Ibid., 916-7.

166. Huggins, "Nebula in the Sword-Handle of Orion," 42. That Huggins was uncomfortable with this conclusion can be inferred from his emphasis on the uncertainty of current knowledge about the structure and composition of the nebulae in an address before the British Association in 1866. See, William Huggins, On the Results of Spectrum Analysis Applied to the Heavenly Bodies (W. Ladd: London, 1866): 29-43. Many years later, in 1891, with years of examining nebular spectra behind him and recently having had the opportunity to examine photographs of nebulae taken by Isaac Roberts, Huggins was emboldened to distance himself publicly from his 1864 position that nebulae were of a totally different form and nature from all other celestial bodies. He had embraced the earlier view, he claimed, while under the influence of religious dogma. Now that he had shed these fetters, he claimed he was once again able to recognize his observations of nebular spectra as providing evidence that celestial bodies are "obviously not a haphazard aggregation of bodies, but a system resting upon a multitude of relations pointing to a common physical cause." Specifically, he argued, these observations support the nebular hypothesis and a universal evolutionary scheme for all celestial bodies. See, William Huggins, "President's Address," Report of the British Association (Cardiff, 1891): 3-37; 20. This will be discussed in more detail in chapter 4.

167. Friedrich Wilhelm and August Dupré were victims of just this problem as they observed what they believed to be a previously unobserved blue line during their spectroscopic examination of London water. In their enthusiasm, they announced the probable discovery of a new element in the calcium group of metals. [see F. W. and A. Dupré, "On the Existence of a Fourth Member of the Calcium Group of Metals," Chemical News 3 (1861): 116-7.] However, as William Crookes related in a letter to a friend even before the article announcing the discovery appeared in print, the blue line turned out to have been "formed by internal reflection from the different surfaces of the prism and lenses." See William Crookes to Greville Williams, 11 February 1861, cited in Frank James, The Early Development of Spectroscopy and Astrophysics, PhD. dissertation, Imperial College of Science and Technology, March 1981, 203.

168. For a discussion of Lockyer's early astronomical work, see Meadows, Science and Controversy, 41-6.

169. In the first letter which Huggins closed "In haste," he took the time to add a note following his signature suggesting that Lockyer, who was considering relocating closer to London, "take a house here [Tulse Hill] with a good garden." Huggins even offered to help Lockyer find a suitable place. William Huggins to J. Norman Lockyer, 20 June 1864, Lockyer papers, Exeter University Library. Meadows draws attention to the fact Huggins may have been more successful than he planned in persuading Lockyer to the benefits of spectroscopic research -- shortly after receiving this letter from Huggins, Lockyer began to make arrangements to obtain a spectroscope for his own telescope. See Meadows, Science and Controversy, 46.

170. William Huggins to J. Norman Lockyer, 20 September 1864, Lockyer Papers, University of Exeter Library. Although Huggins was recognized as sole author of the paper on nebular spectra, as a non-Fellow, he was required to communicate it to the Royal Society through someone who was. Not surprisingly, he chose William Allen Miller.

171. For a discussion of the changes in Royal Society Fellows, see Sir Henry Lyons, The Royal Society 1660-1940 (Greenwood Press: New York, 1968): 125-6; 165-6; 204-5; 232-4; and 275-8. An overview of the changes undergone by the Society between 1830 and 1872, can be found in Marie Boas Hall, All Scientists Now: The Royal Society in the Nineteenth Century (Cambridge University Press: Cambridge, 1984): 62-112.

172. Lyons, The Royal Society 1660-1940, 259-62.

173. Edward Sabine, "President's Address," Proceedings of the Royal Society 13 (1864): 499-502; 502.

174. Ibid., 501.

175. Huggins does not tell us this himself. In his review of Huggins' recent work on the spectra of stars and nebulae for the Astronomical Register, T. W. Burr states that "the labours of Mr. Huggins on the metals taught him the risk of relying on small measured differences, which might be due to variations of temperature and other derangements of the apparatus, and he therefore conceived the idea of exhibiting the spectra of the metals in the same field of view with the stellar spectra." [T. W. Burr], "Spectrum Analysis of the Stars and Nebulae," Astronomical Register 2 (1864): 253-6; 254.

176. Warren De La Rue's Presidential Address delivered 11 November 1864, in Monthly Notices of the Royal Astronomical Society 25 (1864): 1-17; 9. See also "Analysis of Light from the Nebulae," in "Report of the Council," idem., 112-4.

177. [Burr], "Spectrum Analysis of the Stars and Nebulae," Astronomical Register 2 (1864): 253-6; 256.

178. "Progress of Astronomy during the past Year," Monthly Notices of the Royal Astronomical Society 25 (1865): 109-19; 109-10.

179. Ibid., 112.

180. Sabine, "President's Address," Proceedings of the Royal Society 13 (1864): 499-502.

181. This notebook has been labelled "Notebook 2" in the Wellesley collection.

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