‘Land-marks of the universe’: John Herschel against the background of positional astronomy

Summary

John Herschel (1792–1871) was the leading British natural philosopher of the nineteenth century, widely known and regarded for his work in philosophy, optics and chemistry as well as his important research and popular publications on astronomy. To date, however, there exists no extended treatment of his astronomical career. This paper, part of a larger study exploring Herschel's contributions to astronomy, examines his work in the context of positional astronomy, the dominant form of astronomical practice throughout his lifetime. Herschel, who did not himself practice positional astronomy and who was known for his non-meridional observations of specific stellar objects, was nonetheless a strong advocate for positional astronomy—but for very different reasons than the terrestrial applications to which it was most often put. For Herschel, the star catalogues of positional astronomy were the necessary observational foundation upon which information about the stars as physical objects could be constructed. Positional astronomy practiced in the great national observatories was not about navigation or timekeeping; it was a way to standardize stellar observations and make them useful data for constructing theories of the stars themselves. For Herschel, the seeds of the new astronomy emerged from the practices of the old.

Instead of leading a life of dreamy ecstasy or transcendental speculation, the astronomer has, perhaps, more than any man, to give the keenest attention to minute practical details. His life, on the one side, approximates to that of the engineer; on the other, to that of the accountant…. The professional astronomer has hardly any thing to do with the show places of the sky.¹

1. Introduction

The great majority of astronomers working in the early nineteenth century were not interested in stars as physical objects. Far from being bodies with physical properties to be investigated, the stars were seen as markers measured in order to construct an accurate, detailed and precise background against which solar, lunar and planetary motions could be charted, primarily for terrestrial applications. This form of astronomy was practiced in observatories using meridian and transit instruments, and its products were positional star catalogues in which the right ascension and declination of stars were reported in long tables after reduction calculations to take into account precession, nutation, aberration and altitudinal refraction. Besides serving as essential aids for time-keeping, navigation and surveying, these catalogues, and the observatories that produced them, came to be symbols of prestige. They embodied the technical, commercial and practical virtues of precision and instrumental accuracy. This practice of astronomy, the positional astronomy pursued by professional astronomers in national observatories as well as by many amateurs, ultimately came to dominate nineteenth-century astronomy.²

Despite the practical benefits and prestige of positional astronomy, this form of astronomical practice was divorced from considerations of the physical nature of the objects being measured. It was also, as Kevin Donnelly has recently discussed, perceived as dry, tedious and removed from astronomy's romantic appeal, ‘a model of boredom in action’.³ Astronomy had lost its poetry, J. D. Forbes (1809–1868) admitted in an article for the Edinburgh Review in 1850. ‘If a young man has any lingering romance about astronomy’, he wrote, ‘let him try the post of an ordinary assistant at Greenwich for six months, and we believe that he will be “planet-struck” no more’.⁴

By the end of the nineteenth century, popular writers were promoting a view of astronomy that eschewed such numerical tedium and called for a return to a sense of wonder regarding the objects of the universe. As Charlotte Bigg outlines in her article on the rise of astrophysics and its relationship to popular astronomy during this period, popularizers of astronomy ‘complained about the drudgery of positional astronomical work, of the unbearable hierarchies, of the astronomers’ lack of imagination’.⁵ The products of meridional observatories, their dry ledgers of star positions, were contrasted with the new results of astrophysics and the investigations of the physical nature of celestial objects.

Chief among those decrying positional astronomy was Richard Anthony Proctor (1837–1888), one of the most successful of the new popularizers of astronomy of the late nineteenth century.⁶ Proctor admitted the practical benefits of positional astronomy but said ‘there can be no question that the highest place is given…to those rather who have advanced our knowledge of astronomical facts…than to those who have applied astronomy most successfully to practical purposes’.⁷ It was not positional astronomy, in Proctor's view, that yielded up the secrets of the universe. Indeed, the work of the ‘astronomical surveyor’ would only be rendered ineffectual by such investigations. For Proctor, the work of the great astronomers—primary among whom was John Herschel—transcended the tedium of positional astronomy:

The meaning of the stupendous celestial mechanism, the beauty and harmony of the celestial architecture, it is not for the Flamsteeds, the Maskelynes, and the Airys—useful, nay, essential though their work may be—but for the Newtons and Herschels of astronomy, to investigate. It is the celestial scene as viewed and studied by philosophers such as these, not merely as surveyed in Government observatories, that I propose to contemplate…. For astronomy, regarded as a means of philosophic training, owes almost all its value to men of the former type, scarcely any (though commerce owes much) to those of the latter.⁸

Proctor believed that John Herschel's work was of a completely different form to the positional astronomy that dominated most observatories of the nineteenth century. Yet Herschel, as the leading astronomer of his day, had a relationship with positional astronomy that was complex and not as separate from it as Proctor's writings suggest. It is true that Herschel lacked both instrumentation and inclination for pursuing positional astronomy; nonetheless, he was an important spokesman for its practice in the early nineteenth century. In his position as a founder of the Astronomical Society of London and later as its president, he publicly articulated the merits of the star catalogues that resulted from positional astronomy. Moreover, during his time at the Cape of Good Hope in South Africa, Herschel experienced first-hand the need for accuracy in such catalogues for his own work, and on his return to Britain he was given responsibility for overseeing the publication of star catalogues that represented the culmination of this nineteenth-century endeavour in Britain.

Herschel's own astronomical catalogues, on the other hand, were very different in nature. He spelled this out himself, recognizing that the nebular and double star catalogues, for which he became famous, gave relative positions and could not serve the same purposes as positional star catalogues. Herschel's catalogues drew the attention of astronomers to specific objects and provided information about the structure of those objects and their distribution in the heavens, but they did not plot positions with the accuracy necessary for terrestrial applications. Yet for Herschel, the main value of positional catalogues was not in their terrestrial applications but was identical to that of his own relative catalogues: highly accurate positional star catalogues were necessary to arrive at information regarding the nature of the stars. Both his own catalogues and the ‘ledgers full of stars’ of positional astronomy provided an empirical framework against which further observations could be made or earlier observations could be compared. It was only by comparison within such a framework that contemporary observations could provide information on the physical nature of sidereal objects. For Herschel, the information about position given by star catalogues had utility that went far beyond the practical aspects of surveying and timekeeping. While writers like Proctor dismissed such catalogues as narrowly practical, Herschel saw them as important tools for discovery.

In this paper I provide the first detailed analysis of John Herschel's relation with positional astronomy, the dominant astronomical practice throughout his career, and explore how Herschel's work should be understood against the background of nineteenth-century astronomy. I begin in the next section by outlining Herschel's engagement with positional astronomy in three cases: his comments on important positional star catalogues in his official capacity as president of the Astronomical Society (1827–1829), his experiences with southern star catalogues during his years observing at the Cape (1834–1838), and his work on the catalogues initiated and funded by the British Association for the Advancement of Science upon his return to Britain. Through these three forms of engagement, which together spanned his career, I show that Herschel's emphasis was continually on the utility of positional astronomy for an understanding of the stars themselves and not on its practical, terrestrial applications.

Herschel's thoughts on positional astronomy provide the context for the third section, Herschel's ‘celestial reform bill’, an attempt to radically reorganize stellar and constellation nomenclature. For Herschel, celestial reform was necessary to make the sky more accessible, not for those pursuing positional astronomy but for observers investigating the physical nature of the stars. These astronomers, observing specific sidereal objects, required a natural organizational scheme for the heavens to make their observing more efficient. I argue that the motivation behind Herschel's attempts at constellation reform, which have never been explicitly examined, was consistent with his views regarding positional star catalogues: a more orderly heaven, like orderly star catalogues, would assist in the study of the physical nature of celestial objects.

Finally, in the concluding section I outline how Herschel's perceptions and practice regarding star catalogues, both positional catalogues and his own relative and more selective catalogues, manifested his philosophy of science. Throughout Herschel's career, he viewed star catalogues as the means for providing the raw positional data required to gain new insights into the nature of the sidereal universe and its laws. Positional data were not simply about position; they were a tool to compare proper motions and stellar magnitudes, note new objects and measure parallax. As Marvin Bolt has discussed, Herschel had a two-tiered approach to science in which observers gathered data that were then fed to mathematically-trained theorists who used these data to form more general laws.⁹ Herschel's view of positional astronomy was part of this well-developed program of scientific discovery.

By examining Herschel's relationship with the positional astronomy that dominated nineteenth-century astronomy, I highlight the uniqueness of his own work during this period. Herschel's astronomy was not positional. Like the work of his father William Herschel (1738–1822), it consisted of systematic study of specific celestial objects, the form of astronomy that would be taken up by many other observers as Herschel's life went on. Indeed, his work should be seen as both the impetus and exemplar of such practice. Herschel was acknowledged by the public and other astronomers as a master of precise observation and sophisticated mathematical treatment. His position at the centre of the astronomical community gave him a stature at least equal to that of any contemporary astronomer. In the eyes of the public, his work embodied the romantic appeal of classical observational astronomy, a perception that arose from the results of his astronomical labours: not simply ledgers of stars but dynamic accounts of physical stellar objects.

2. Herschel and positional star catalogues

In his 1820 address to the newly formed Astronomical Society of London, John Herschel told the gathered members,

One of the first great steps towards an accurate knowledge of the construction of the heavens, is an acquaintance with the individual objects they present: in other words, the formation of a complete catalogue of stars and other bodies, upon a scale infinitely more extensive than any that has yet been undertaken; and that shall comprehend the most minute objects visible in good astronomical telescopes.¹⁰

This description of the aims of astronomy is in keeping with the precise positional measurement and calculation for which nineteenth-century astronomy became known. This method of precision determination of star positions followed by mathematical reduction dominated the established observatories of Britain and Europe. Its practitioners seemed disengaged from the sense of the wonder that astronomy afforded in popular perception. Herschel later referred to this practice, focused on ‘meridian observation, star-corrections, and improvement of the Nautical Almanac’ as the ‘chilling torpor of routine’.¹¹ The first phrase of the above quote, ‘an accurate knowledge of the construction of the heavens’, hints at his early desire for something more.

Though Herschel's work was emblematic of a different sort of astronomy from the purely positional, he acknowledged the importance of such astronomical practice and depended upon its results for his own work. He engaged in and garnered support for vast programs of data-gathering in fields such as tidal recording, meteorological studies and terrestrial magnetism surveys that paralleled the immense amount of observation and reduction required in positional astronomy.¹² Herschel's social status and achievements in mathematics and natural philosophy placed him in the upper echelons of the British astronomical community, where he functioned between the ‘celestial accountants’ like George Biddell Airy (1801–1892) and Francis Baily (1774–1844) and observers with wider interests such as William Rutter Dawes (1799–1868) and William Henry Smyth (1788–1865).

Herschel's astronomical fame came to rest largely on his comprehensive and detailed catalogues of nebulae and double stars in the northern and southern hemispheres. His project of sweeping the heavens differed significantly from the meridian and transit observations that resulted in the great positional catalogues of the nineteenth century, but his comments on such catalogues show that he viewed the ultimate outcome of both of these works in a similar manner. Catalogues for Herschel did not simply provide a static, fixed background against which to map planetary motions or aid navigation. They were structured to synthesize and present data about physical objects. Indeed, as Herschel pointed out in his address to the Astronomical Society:

It is possible that some bodies, of a nature altogether new, and whose discovery may tend in future to disclose important secrets in the system of the universe, may be concealed under the appearance of very minute single stars, no way distinguishable from others of a less interesting character, but by the test of careful and often repeated observations.¹³

Only by careful, structured observation—and by having positional catalogues against which new observations could be compared—would such objects become apparent. For Herschel at the time of the Astronomical Society's birth, the reason for creating catalogues was to reveal the properties of objects in the sky. This, however, was not the prevailing attitude among the other founders of the Society.

As William Ashworth has argued in his study of the Astronomical Society, the Society's founders applied the bookkeeping practices of commercial and financial enterprise to astronomy. Ashworth points out that the core group who founded and guided the Society in its early years had backgrounds in commerce or finance and saw the job of establishing ‘the motion and position of the heavens as complementary to their other task of calculating risks, policy premiums and dividends’.¹⁴ For them, the Society's role was to advance astronomy through standardization by gathering and ordering positional observations and producing uniform catalogues. As Simon Schaffer explains, ‘The ideal observatory became indistinguishable … from a Whitehall office, with its ledgers full not of “income tax schedules” but stars’.¹⁵ A history of the Society notes that, despite Herschel's initial admonitions to uncover new secrets in the system of the universe, there is ‘ample evidence in the history of the early years of the new Society that its prime motive was “precise measurement and systematic calculation”’.¹⁶

Whatever his own feelings, Herschel publicly supported the methods and products of positional astronomy throughout his career. In his address to the Society in 1827 on the occasion of awarding Francis Baily the Society's gold medal for his catalogue of 2,881 principal stars, Herschel distinguished between two types of catalogues. The first is the type William Herschel created and for which John Herschel would gain fame: ‘a mere list of objects placed on record, to fix on them the attention of astronomers, and to afford them matter for observation’. The second type of catalogue is ‘a collection of well-determined zero points, offering ready means of comparing their observations with those of others, and of detecting and allowing for instrumental errors’.¹⁷ Herschel celebrated Baily's work on this second type of catalogue, the positional star catalogue, which would come to embody nineteenth-century astronomy.

The merits of positional catalogues, Herschel admitted, lay in their practical utility, not their speculative utility: ‘not to settle mere speculative points in the doctrine of the universe; not to cater for the pride of man, by refined inquiries into the remoter mysteries of nature’. Rather, by establishing precise positions of stars, the ‘land-marks of the universe’, such catalogues allowed the stars to serve astronomers, geographers, navigators and surveyors, as points of departure.

[The stars are] the same for ever and in all places, of a delicacy so extreme as to be a test for every instrument yet invented by man, yet equally adapted for the most ordinary purposes; as available for regulating a town clock, as for conducting a navy to the Indies; as effective for mapping down the intricacies of a petty barony, as for adjusting the boundaries of transatlantic empires.¹⁸

Herschel's rhetoric of the stars as ‘land-marks of the universe’ aiding in a host of practical applications on the Earth was repeated in the works of other astronomers during this period. William Henry Smyth, an observer who corresponded extensively with Herschel, reproduced the quotation from Herschel's address in full in the first volume of his Cycle of Celestial Objects (also known as the Bedford Catalogue), emphasizing that accurate stellar positions are eternal monuments remaining long after the astronomer who made them and his instruments are gone.¹⁹ Herschel's tacit endorsement of positional astronomy was also repeated in Descriptive Astronomy by George F. Chambers (1841–1915), a popular astronomy text that went through multiple editions in the second half of the nineteenth century.²⁰

Herschel could speak with authority on the mathematical reductions involved in positional astronomy. In 1822, he published a long paper in which he outlined mathematical methods for reducing stellar observations to take account of precession, aberration and nutation for principal stars. In this paper he emphasized the merits of such methods for the individual observer.

If he will only consent to take for granted these invaluable data, which the labour of so many excellent observers, and the expenditure of so large a portion of the national wealth has been devoted to furnish … his work will flow easily under his hands.²¹

The observer could devote to making observations the time he saved by using tables of reduced star positions to avoid long calculations. Herschel also had extensive knowledge of the equipment and observational procedures used in positional astronomy, providing in his 1833 Treatise on Astronomy detailed descriptions of the instruments and methods involved.²²

Yet his 1822 paper remained Herschel's only direct contribution to the practice of positional astronomy, though he applied reduction methods to his own observations and, as will be seen, was eventually charged with overseeing the printing of significant positional catalogues. Though he had mastery of the mathematical techniques, Herschel did not possess the instruments needed to create positional star catalogues. Positional astronomy was identified almost entirely with the building and instruments of a permanent observatory.²³ In contrast to this, ‘Herschelian astronomy’ required giant reflectors that must be used out-of-doors. Though famous for his observations, Herschel had no observatory.

Though Herschel lauded positional astronomy in discussing Baily's work in his 1827 address, he was more circumspect in his correspondence. In a letter written to the Scottish astronomer William Wallace (1768–1843) in 1825, Herschel hoped Wallace would ‘set a good and meritorious example by departing from the dull routine followed in our observatories, and giving the world an account of some other celestial object than those 36 or 360 stars one is sick to death with hearing of’. German astronomers, he wrote, were ‘clearing the heavens’ and would soon leave the British with nothing left to discover. ‘They are observing the heavens’, he complained, ‘while we are discussing the merits of our instruments’. He wished ‘some public body or some real amateurs with money enough, would do a bold thing’ and begin observations on Bessel's program.²⁴

The paradox in Herschel's private statements to Wallace is that the work of Friedrich Bessel (1784–1846) was seen as the epitome of positional astronomy. Herschel himself referred to Bessel's work as ‘the perfection of astronomical bookkeeping’.²⁵ But for Herschel, the true merit of Bessel's precise positional catalogues was that they extended to an immense number of dim, hitherto neglected stars. In his address to the Astronomical Society in 1829 on the occasion of awarding Bessel the Society's gold medal for these catalogues, Herschel explained that the problem with astronomy of recent years had been that ‘the attention of astronomers, in fixed national observatories … was almost exclusively confined to observations of the sun, moon, and planets, and a moderate number of the principal fixed stars’. Such bright stars were useful for navigational purposes, but this resulted in the neglect of ‘the minor host of heaven’. Astronomers, Herschel went on, ‘like the vulgar, had been too much influenced by appearances and glitter, and had fallen into habitual neglect of the rest, or contented themselves with rough approximations of their places’. Detailed catalogues like Bessel's that took into account dimmer stars were necessary because only such surveys could reveal stellar properties such as proper motion or parallax.²⁶

For Herschel, precise positional catalogues were empirical tools for establishing the physical properties of the sidereal universe:

How unworthy is it of those who call themselves philosophers to let these great phenomena of nature—these slow, but majestic, manifestations of the power and glory of God—glide by unnoticed, and drop out of history, beyond the power of recovery, because we will not take the pains to note them in their unobtruding and furtive passage; because we see them in their every-day dress, and mark no sudden change; and conclude that all is dead, because we will not look for the signs of life; and that all is uninteresting, because we are not impressed and dazzled.²⁷

It might be, Herschel continued, that some ‘minute and telescopic atom will perhaps have become the stepping-stone between our system and the starry firmament’.²⁸ Bessel's catalogues, the epitome of early nineteenth-century positional astronomy, were for Herschel empirical data to derive laws and build theories about the sidereal universe and the distances and distribution of stars.

Not all astronomers viewed positional catalogues as Herschel did. Airy, for example, in an address to the British Association for the Advancement of Science just a few years after Herschel's remarks regarding Bessel's catalogues, presented a much more constrained view of the scope of astronomy. He remarked on the application of mathematical techniques to the motion of the Sun, planets, asteroids and comets but said almost nothing regarding sidereal astronomy beyond meridian instruments and positional catalogues.²⁹

Herschel in his public commentary on positional star catalogues did not neglect their practical, terrestrial aspects. For example, he pointed out that the importance of positional catalogues for the southern skies lay in their ‘practical interest’

now that civilization and intercourse are rapidly spreading through those distant regions…. It is no longer possible to remain content with the limited and inaccurate knowledge we have hitherto possessed of southern stars, now that we have a new geography to create, and latitudes and longitudes without end, to determine by their aid.

Herschel made these remarks in his capacity as Astronomical Society president, awarding honorary medals for the positional catalogue overseen by Thomas Brisbane (1773–1860) during his time as Governor of the Colony of New South Wales. Even here though, Herschel was quick to emphasize, perhaps foreshadowing his own intentions regarding the southern skies, that such catalogues also served to ‘open up these treasures of the southern sky, and display to mankind their secret and intimate relations’.³⁰

Besides Herschel's public commentary on the role of positional star catalogues, he was aware of their importance to his own observations. As he explained in the introduction to his 1826 catalogue of observations made with his 20-foot reflecting telescope at Slough, each of his observational sweeps included zero stars used as reference points. Herschel's own catalogues were relative catalogues, giving the position of observed objects with respect to these zero stars. Because of this, he depended on the accuracy of their positions from other catalogues. If ‘the places of new objects cannot in general be ascertained with precision enough to identify them with certainty’, Herschel wrote, telescopes ‘degenerate from astronomical to mere star-gazing instruments’. Precision measurement was what ensured astronomical observations were useful and could contribute true scientific knowledge. Yet the precision of his own catalogues did not match that of positional catalogues. The error, Herschel explained, in his catalogues

may seem a large quantity to those who are accustomed to the delicacies of fixed instruments; but it will be recollected that the only objects aimed at in the determination of the places of bodies in sweeping with this instrument, are their complete identification, and the power of finding them again with certainty in future.³¹

Even though Herschel was not concerned to mark the positions of nebulae or double stars with the same degree of precision as that obtaining in positional catalogues, Herschel's catalogues were built on reference frames provided by the zero stars from these underlying catalogues.

Accurate positional catalogues were easy to come by for Herschel's work observing the northern skies from Britain, but during his time at the Cape their lack vividly illustrated to him how much his own work depended on accurate positional astronomy. When he left England, Herschel's plan was to use the star positions given in the Brisbane Catalogue, a catalogue of southern stars undertaken under the patronage and assistance of Governor Brisbane at the Parramatta Observatory he had founded in New South Wales.³² Unfortunately, Herschel quickly found these catalogues inadequate to his task and became reliant on Thomas Maclear (1794–1879), the Royal Astronomer at the Cape, for the accurate star positions against which to position the objects in his sweeps. The letters between Maclear and Herschel during Herschel's time at the Cape often involved Herschel providing Maclear with lists of stars he needed accurate positions for and Maclear sending back the positional measurements obtained using the Cape Observatory's transit circle. By Herschel's second year observing in South Africa, he remarked to Maclear with evident frustration that the errors in the Brisbane Catalogue were enough to make Herschel feel it an insult to the Governor to call the catalogue by his name:

Henceforth therefore I feel disposed to disuse the epithet Brisbane Catalogue as connected with this remarkable record, and rather to designate it by the names of those concerned in its composition—It is worthy of the Age of Uluj Beg [sic] or Tycho Brahe.³³

Ultimately Herschel put so little faith in this catalogue that he wrote that using it led to ‘the certainty of often committing irrevocable error’.³⁴ The frustration and loss of time this entailed during his time at the Cape illustrated the practical necessity of positional astronomy for Herschel's own work as well as the need for more precise and accurate southern star catalogues.

Herschel's loss of faith in the Brisbane Catalogue likely influenced the advice he gave the new Governor of New South Wales on the proper use of the Parramatta Observatory. Herschel's suggestions to George Gipps (1791–1847) reveal his conceptions on the differences between positional astronomy, for which well-equipped professional observatories were suited, and the useful work that could be done in those like Parramatta, which did not have the necessary instrumentation or staff. Parramatta Observatory could not be ‘considered as belonging to those of the first class, nor are its means competent to grapple with any of the fundamental points of sidereal astronomy’. The large national observatories should pursue positional astronomy, ‘undertaking to better with additional precision the places of the fundamental stars’. An observatory like Parramatta (and by implication those operated by private observers throughout Britain) could offer valuable contributions to astronomy by focusing on mapping stars of lesser magnitudes and by observing double stars.³⁵ There was an important place for such ‘second class’ observatories, but it was outside the field of traditional positional astronomy.

John Herschel's final contribution to positional astronomy also stemmed from his time at the Cape. Though the Parramatta catalogue was unreliable, there was still a vast collection of observations made by the French astronomer Nicolas-Louis de Lacaille (1713–1762) during his time observing at the Cape from 1751 to 1753. A fraction of these observations had been reduced and published, but the majority of the data providing positions of 9766 stars remained unreduced, unpublished, and therefore inaccessible and useless to astronomy.³⁶ In 1838, almost immediately upon his return from the Cape, Herschel was nominated by the British Association to a committee charged with overseeing the reduction and printing of these observations.

The reductions were completed in 1840, and the Association granted Herschel's committee almost two hundred pounds to see the work to publication. This amount increased over subsequent years until the catalogue was finally published in 1847, after delays owing to the deaths of Francis Baily and Thomas Henderson (1798–1844), the chief computer. In the preface Herschel composed for this catalogue, he did not write of the catalogue's use for navigation or the utility of southern stars to commerce, colonial surveying, or the administration of empire. Instead, he presented the catalogue in the same way as he had Bessel's decades earlier: it would aid in developing an understanding of the sidereal universe. Lacaille's observations in their unreduced state remained ‘useless for purposes of comparison with the present state of the heavens’, but reduced and published, Herschel explained, they could be used to ‘settle many important questions respecting proper motion’.³⁷ In other words, the exact locations of Lacaille's nearly ten thousand stars, which the British Association for the Advancement of Science ultimately spent several hundreds of pounds in printing, served to construct a more complete picture of stellar dynamics.

For Herschel, the primary utility of star catalogues remained arriving at new insights into the nature of the sidereal universe. Stellar positions were the data by which astronomers could detect new properties of the celestial regions and the observational foundation upon which they constructed theories. In this respect, star catalogues were analogous to the record of tides, temperatures and magnetism that Herschel participated in gathering, organizing and standardizing. Herschel's own catalogues, giving the relative locations of thousands of double stars and nebulae, depended on positional astronomy but superficially differed from it by bringing specific new objects into astronomical purview. Yet for Herschel, the purely positional star catalogues that characterized professional nineteenth-century astronomy ultimately served this same purpose: bringing the true nature of the stars into view.

3. Herschel's celestial reform bill

Before concluding with a discussion of how Herschel's work on positional astronomy illustrates his philosophy of science, one additional aspect of his work must be explored: his agitation for a radical reform of the constellations and stellar nomenclature. The catalogues that painstakingly provided right ascension and declination for tens of thousands of stars were hobbled, Herschel believed, by inconsistent star naming conventions and by the complicated, confusing and often contradictory borders of the constellations. For star catalogues to be useful, observers needed clarity regarding which stars different catalogues referred to and where the actual borders of the constellations lay. Herschel's desire for celestial reform was activated by his view that star catalogues should serve observers studying the nature of the stars. Though muddled references to particular stars or to an object's location relative to constellation boundaries would not matter to observers equipped with precise transit instruments, it was of great importance to those—like Herschel—whose telescopes searched the skies for particular objects. The observers who wished to measure double star positions or observe the magnitudes of variable stars needed clear and non-contradictory star maps. This necessitated drastic celestial reform.

Herschel mentioned the capriciousness of contemporary constellation boundaries in his 1833 Treatise on Astronomy. After discussing the celestial sphere and its coordinates, he continued:

Of course we do not here speak of those uncouth figures and outlines of men and monsters, which are usually scribbled over celestial globes and maps, and serve, in a rude and barbarous way, to enable us to talk of groups of stars, or districts in the heavens, by names which, though absurd or puerile in their origin, have obtained a currency from which it would be difficult, and perhaps wrong, to dislodge them. In so far as they have really (as some have) any slight resemblance to the figures called up in imagination by a view of the more splendid ‘constellations’, they have a certain convenience; but as they are otherwise entirely arbitrary, and correspond to no natural subdivisions or groupings of the stars, astronomers treat them lightly, or altogether disregard them.³⁸

Herschel was particularly troubled by the unnatural divisions the constellations provided in contrast to natural divisions in the sky such as the Milky Way or the ecliptic. In a note on this passage, he explained that most working astronomers ignored the constellations, as these figures

seem to have been almost purposely named and delineated to cause as much confusion and inconvenience as possible. Innumerable snakes twine through long and contorted areas of the heavens, where no memory can follow them; bears, lions and fishes, large and small, northern and southern, confuse all nomenclature, &c. A better system of constellations might have been a material help as an artificial memory.³⁹

Herschel's time at the Cape of Good Hope did nothing to soften his views on this matter. In 1836, as his frustration with the Brisbane catalogue grew, he wrote to Thomas Maclear asking his opinion on some principles of constellation reform, ‘it being presumed that the actual system is intolerable’. Among the nine principles of reform Herschel proposed, most had to do with clarity, ease of use and the elimination of errors during catalogue production. For example, he suggested no two constellations have the same name or the same first syllable or consist of more than one word. He also suggested that, while retaining Greek letter designations for brighter stars, certain letters that caused frequent typographical errors should be eliminated. His final suggestion would have done away with constellations like Charles's Oak and the recent (and perhaps embarrassing) Herschel's Telescope by allowing no constellation to ‘bear allusion to modern Political Events or to the names of persons born within 1000 years from this time’.⁴⁰

One way to promulgate such reform was to deploy it in new star catalogues. Maclear, for instance, supported Herschel's suggestions, agreeing that the ‘dimensions & thorny figures of the constellations is [sic] so bad that almost any change … must be for the better’. He volunteered to put the changes into place in the printing of his own observations. ‘I am not afraid of censure from the Govern[men]t if you will back me’, Maclear told Herschel. ‘The ice thus broken will facilitate the melting down of a farrago of figures that to say the least … are a hindrance in the maps, and a confusion in the catalogues’. Maclear urged Herschel to make definite plans for how the constellation boundaries would be determined.⁴¹

In a letter of the following month, Maclear resumed discussion of constellation reform, noting that the work of Francis Baily and Baily's suggestions for similar changes made Herschel's proposals timely. Upon Herschel's return to Britain, the catalogues produced under Baily's guidance for the British Association provided the best opportunity for putting Herschel's suggestions in place. At this early date though, Maclear was unsure how far Baily was ‘prepared to cut & slash’. Maclear compared celestial reform to contemporary political reform in Britain, noting wryly:

in this reform, there is neither Mother Church nor a house of Peers—Patrons of Burroughs or Balywicks [sic] to conciliate. Nor need there be any quarrelling about the application of the surplus revenue from the Estates of Solitarius or the bogs of Aquarious [sic].⁴²

Maclear was not alone in comparing Herschel's proposals for celestial reform to the controversial Reform Bill passed by Parliament in 1833, which had redistributed voting districts and increased the electoral franchise. Herschel's close friend William Whewell (1794–1866) said Herschel's plan was ‘a reform bill for the stars: improving the representation of the skies … and arranging the boundaries of [constellations] according to their star-population’.⁴³

About a year after first raising the issue, Herschel returned to the question, writing Maclear to set out another series of principles that Herschel wished to propose at the upcoming meeting of the British Association, by which time he would be back in England. The proposals here were generally the same, though he now suggested eliminating Greek letter designations altogether.⁴⁴ In Herschel's suggestions, both his personal preferences as well as his belief in the utility of such reforms for amateur astronomers came into play. He wanted all star and constellation names to ‘be classical—good—easily pronounced Latin words of not more than three syllables, having regularly formed genitive cases’ and the exclusion of names of astronomers and any ‘great men’ since 1000 AD. His rather sweeping naming scheme proposed that all stars be given names of individual heroes or demigods of antiquity, constellations be named for ‘Classes of men’ and clusters ‘by recognized Classical assemblages’. Variable stars figured in his considerations: they were to be lettered according to their mean magnitudes and conspicuous examples were to be given proper names, which would greatly aid variable star observers. Finally, Herschel suggested that as an aid to memory the constellations should be alphabetized according to right ascension, ‘a great practical convenience’.⁴⁵

Herschel's diaries indicate that he discussed constellation reform with Airy, now the Astronomer Royal, soon after his return from the Cape in 1838.⁴⁶ Herschel had an opportunity to present his celestial reform bill at the 1840 meeting of the British Association, where he was placed on a committee to consider this topic with Whewell and Baily. He outlined his views in a paper to the Royal Astronomical Society published in its Memoirs in 1842. Here Herschel made it explicit that those who would most benefit from constellation reform were not the practitioners of positional astronomy but instead

another and a very important class of observers, to whom the present system of constellations, and the actual state of the charts generally accessible, is a real and most serious grievance; I mean those who devote their attention to the physical departments of practical astronomy, such as require a perfect familiarity with the aspect of the heavens, as seen by the naked eye in the open air, whether for the purpose of pointing reflecting or other telescopes, not mounted meridionally or equatorially [sic], to particular objects (such as double stars, nebulae, &c.), or for that of photometrical determinations, and for the investigation of variable and periodical stars. These last are subjects of great and growing interest, and there is, I think, no exaggeration in declaring it impossible to go fully into them under the present system of nomenclature and distribution.⁴⁷

In short, it was the observers practicing Herschelian astronomy, those investigating the physical nature of stars and not their positions alone, who were in need of this celestial reform. These astronomers did not work in observatories timing the passage of stars at the meridian. They made observations and measurements of specific objects, and they needed to be able to find these objects without constant reference to maps or charts. Having a simple arrangement of constellations in one's head would necessitate less map-reading, which destroyed night vision and in particular made accurate variable star observing impossible. ‘Bad charts’, Herschel explained, ‘need to be consulted more often and ruin viewing vision’.⁴⁸ Like precise positional star catalogues, constellation reform was required to adequately and naturally represent the heavens and organize observational data.

Herschel was willing to go to some lengths to ‘naturalize’ the heavens and bring them into better order for the aid of memory. Besides the suggestions he had already made for doing away with confusing nomenclature, in his published proposal of 1842, he again suggested making all constellations general titles or classes from antiquity. This would still allow mapmakers, ‘if, indeed, the inveterate practice of disfiguring celestial charts with pictures is to be perpetuated’, to illustrate particular constellations as whatever specific personalities they chose. The names of proper stars should be completely revised, as the names ‘retained in common use … being Arabic words of difficult pronunciation, and uncertain spelling, have (very properly) become exploded’. Instead, stars should be given names relative to the constellations in which they were found (for example, names of Argonauts in the constellation Navis [Ship]) or after famous explorers. In perhaps his most radical suggestion, Herschel proposed naming the stars in chronological order, beginning with the twelfth century BC at zero degrees right ascension, proceeding to the constellation of the Cross at twelve hours right ascension, and completing the circle with AD 1200, ‘giving to remarkable stars, in each hour, the names of worthies of the corresponding century’. Amazingly, Herschel seemed to believe this would avoid contemporary controversy.⁴⁹

Ultimately, Herschel had to be satisfied with much less sweeping reform. His diaries indicate multiple meetings with Baily to discuss the matter, and in a report of the committee for revising stellar nomenclature made to the British Association in 1843, Herschel and his fellow committee members noted they would postpone any changes until upcoming German catalogues had been purchased and reviewed.⁵⁰ In a paper the following year providing further remarks on his proposed revisions, Herschel acknowledged resistance to his more drastic changes and offered a more modest set of revisions. In the southern hemisphere, constellations would be slightly altered: the unwieldy constellation Argo would be split into four constellations, but the rest of Lacaille's constellations would be retained, with doubtful stars sorted accordingly and all two-word constellation names revised into a single word.⁵¹

In 1844, Herschel's committee made its final report. There were now three significant positional catalogues underway by the instigation and support of the British Association: the British Association catalogue, Lacaille's southern catalogue, and Baily's reduction of the immense Histoire céleste of Jérôme Lalande (1732–1807).⁵² The moderate reforms already outlined were put into place in these works, but Herschel's original goal of totally revising the southern constellations was not—nor his audacious plans for stellar nomenclature. Yet Herschel's desire to make star catalogues more useful to those pursuing physical as opposed to purely positional astronomy was still apparent: the committee indicated in its report that it believed

for certain astronomical purposes, although not those to which catalogues of stars arranged in order of right ascension are especially applicable, such a remodelling, not only of the southern constellations but of those in both hemispheres, is both desirable and necessary.⁵³

Herschel's attempts at celestial reform illustrate his view of positional star catalogues and star maps as tools for organizing the data of the heavens in useful ways for those who were, like himself, interested in studying specific sidereal objects, particularly double stars and variable stars. More than tools for timekeeping or navigation, highly accurate positional catalogues were necessary for studying the changing brightness or position of the stars themselves. Although the creators of such catalogues did not need revisions to constellation or stellar nomenclature, those astronomers pursuing non-positional astronomy would have found them very useful. It was this consideration, illustrated by his own experiences, that led Herschel to argue for such reform.

4. Conclusion: positional astronomy and Herschel's philosophy of science

Herschel's view of the role of positional astronomy is an ideal example of his philosophy of science in action. As Bolt has argued convincingly, Herschel should not be understood as merely a naïve Baconian. Instead, Bolt explains that though ‘Herschel emphasized that [empirical, inductive] part of the investigative process for the novice natural philosopher’, he advocated ‘a more hypothetico-deductive technique for experts’.⁵⁴ For Herschel, science was more than simply casting an empirical net over the world and noting what patterns emerged. It was an iterative process by which intentional observation and measurement were interpreted within a mathematical framework to determine probable causes of phenomena. For this iterative process to be effective, however, observations had to be rendered useful. This was for Herschel the ultimate purpose of star catalogues. Herschel stated this in his Preliminary Discourse on the Study of Natural Philosophy, which was published in 1830 and in which he set out his philosophy of science. Here he outlined the importance of star catalogues in terms of the physical nature of celestial objects:

The comparison of catalogues, published at different periods, has given occasion to many curious remarks, respecting changes of place and brightness among the stars, to the discovery of variable ones which lose and recover their lustre periodically, and to that of the disappearance of several from the heavens so completely as to have left no vestige discernible even by powerful telescopes. In proportion as the construction of astronomical and optical instruments has gone on improving, our knowledge of the contents of the heavens has undergone a corresponding extension, and, at the same time, attained a degree of precision which could not have been anticipated in former ages.⁵⁵

Herschel went on to say that in recent years the expansion of star catalogues to include very dim stars (likely referring to Bessel's catalogues) had continued this process and ‘led to the discovery of innumerable important and curious facts, and disclosed the existence of whole classes of celestial objects, of a nature so wonderful as to give room for unbounded speculation on the extent and construction of the universe’.⁵⁶ Star catalogues were the raw material with which the astronomer could arrive at conclusions regarding the nature of the universe and the stars in particular.

Herschel's view of stellar catalogues was also in harmony with his views on the utility of gathering large amounts of data in other fields, such as Whewell's immense tidal observation program. Herschel drew parallels between the practices of astronomy at observatories and the enormous effort to observe, record and standardize tidal, meteorological and magnetic observations around the world. Indeed, he often cited such physical observations as an important aspect of the work of astronomical observatories.⁵⁷ In his dual review of Whewell's History of the Inductive Sciences and The Philosophy of the Inductive Sciences, Herschel praised Whewell's recommendation of a ‘“continued and connected system of observations and calculations,” imitating the system which has been found so efficacious in astronomy’ and said it ‘should be extended to other branches of science’, particularly magnetic and meteorological observations.⁵⁸ Such effort to gather and process the data was necessary, Herschel believed, for the construction of theories and the discovery of laws governing physical processes.

Herschel ultimately spelled out the connection between this form of world-wide, empirical endeavour and the practices of positional astronomy in his 1845 address to the British Association for the Advancement of Science:

The establishment of astronomical observatories has been, in all ages and nations, the first public recognition of science as an integrant part of civilization. Astronomy, however, is only one out of many sciences, which can be advanced by a combined system of observation and calculation carried on uninterruptedly; where, in the way of experiment, man has no control, and whose only handle is the continual observations of Nature as it developes [sic] itself under our eyes, and a constant collateral endeavour to concentrate the records of that observation into empirical laws in the first instance, and to ascend from those laws to theories.⁵⁹

Bacon, in the New Organon, remarked that ‘simple experience … if taken as it comes, is called accident; if sought for, experiment’.⁶⁰ For Herschel, simple observation of the night sky was accidental unless it was structured and directed observation, dependent upon accurate and detailed stellar catalogues. Only then could the result of such observation properly be called experiment. This was the end to which Herschel applied his own catalogues and how he interpreted the positional catalogues that became a defining characteristic of nineteenth-century astronomy. The fundamental task of astronomers, according to Herschel, was not to build more precise positional catalogues in order to more accurately aid in navigation, cartography, or even national prestige, rather it involved the search for causes of natural phenomena. For Herschel, positional astronomy was always about the stars, their changes and their nature as physical objects.

Acknowledgements

This research was conducted while a graduate fellow in the program for the history and philosophy of science at the University of Notre Dame. I am indebted to Michael Crowe, Marvin Bolt, James Turner and Christopher Hamlin for extensive commentary and critique of early drafts of this work. Part of my research was supported by a Graduate Student Research Grant from the Institute for Scholarship in the Liberal Arts at the University of Notre Dame.

Disclosure statement

No potential conflict of interest was reported by the author.

Notes

¹ E. Walter Maunder, The Royal Observatory Greenwich: A Glance at its History and Work (London, 1900), p. 15.

² For a general discussion of the role of observatories in the nineteenth century, see David Aubin, Charlotte Bigg, and H. Otto Sibum, ‘Introduction: Observatory Techniques in Nineteenth-Century Science and Society’, in The Heavens on Earth: Observatories and Astronomy in Nineteenth-Century Science and Cuulture, edited by Aubin, Bigg and Sibum (Durham, NC, 2010), pp. 1–32, and Robert W. Smith, ‘Remaking Astronomy: Instruments and Practice in the Nineteenth and Twentieth Centuries’, in The Cambridge History of Science: Volume 5, Modern Physical and Mathematical Sciences, edited by Roy Porter and Mary Jo Nye (Cambridge, 2003), pp. 154–73. For the role of positional astronomy in Britain, see Robert W. Smith, ‘A National Observatory Transformed: Greenwich in the Nineteenth Century’, Journal for the History of Astronomy, 22 (1991), 5–20, and David W. Dewhirst, ‘Meridian Astronomy in the Private and University Observatories of the United Kingdom: Rise and Fall’, Vistas in Astronomy, 28 (1985), 147–58.

³ Kevin Donnelly, ‘On the Boredom of Science: Positional Astronomy in the Nineteenth Century’, The British Journal for the History of Science, 47 (2013), 479–503 (p. 481).

⁴ [J. D. Forbes], ‘National Observatories—Greenwich’, Edinburgh Review, 184 (April 1850), 300–356 (p. 349).

⁵ Charlotte Bigg, ‘Staging the Heavens: Astrophysics and Popular Astronomy in the Late Nineteenth Century’, in Heavens on Earth (note 2), 310.

⁶ For more on Proctor and his role in late-Victorian science, see Bernard Lightman, Victorian Popularizers of Science: Designing Nature for New Audiences (Chicago, 2007), 295–351.

⁷ Richard A. Proctor, The Old and New Astronomy (London, 1892), p. 7.

⁸ Richard A. Proctor, The Old and New Astronomy (London, 1892), p. 9.

⁹ Marvin Bolt emphasizes this division in terms of the hypothetico-deductive approach, which was reserved for highly trained natural philosophers, and the inductive approach, which was the method best suited for amateurs. I argue that in Herschel's astronomical practice, this resulted in attempts to make observations by less sophisticated observers more useful by making constellation nomenclature more orderly. Such observations could then become material for the construction of mathematical theories or models. Bolt finds this approach in Herschel's presentation of astronomy, in which ‘anyone, including rank amateurs … could conduct important astronomical observations’, though Bolt does not explore how Herschel thought this could be done. (Marvin Bolt, ‘John Herschel's Natural Philosophy: On the Knowing of Nature and the Nature of Knowing in Early-Nineteenth-Century Britain’, PhD Dissertation, University of Notre Dame, 1998, p. 479.)

¹⁰ John Herschel, ‘Address of the Society Explanatory of their Views and Objects’, Memoirs of the Astronomical Society of London, 1 (1822), 1–7 (p. 4). The Society became known as the Royal Astronomical Society on gaining its royal charter in 1831.

¹¹ H.H. Turner, ‘The Decade 1820–1830’, in History of the Royal Astronomical Society 1820–1920, edited by J.L.E. Dreyer and H.H. Turner (London, 1923), p. 26. Herschel uses this phrase in his ‘Memoir of Francis Baily’, in Francis Baily, Journal of a Tour in Unsettled Parts of North America in 1796 & 1797 (London, 1856), p. 24.

¹² For Herschel's role in magnetic surveys in particular, see John Cawood, ‘The Magnetic Crusade: Science and Politics in Early Victorian Britain’, Isis, 70 (1979), 492–518.

¹³ Herschel, ‘Address of the Society’ (note 10), p. 3.

¹⁴ William J. Ashworth, ‘The Calculating Eye: Baily, Herschel, Babbage and the Business of Astronomy’, The British Journal for the History of Science, 27 (1994), 409–41 (p. 410).

¹⁵ Simon Schaffer, ‘Astronomers Mark Time: Discipline and the Personal Equation’, Science in Context, 2 (1988), 115–45 (p. 120).

¹⁶ Turner, ‘The Decade 1820–1830’ (note 11), 25.

¹⁷ John Herschel, ‘An Address delivered … on the Occasion of the Distribution of the Honorary Medals … on April 11, 1827, to Francis Baily …’, Philosophical Magazine, 2 (1827), 455–66 (p. 456).

¹⁸ John Herschel, ‘An Address delivered … on the Occasion of the Distribution of the Honorary Medals … on April 11, 1827, to Francis Baily …’, Philosophical Magazine, 2 (1827), 455–66, pp. 456–7.

¹⁹ William Henry Smyth, A Cycle of Celestial Objects for the Use of Naval, Military and Private Astronomers, 4 vols (London, 1844), vol 1, p. 269. Smyth's Cycle provides an example of Herschel's first type of catalogue, a descriptive catalogue of objects of interest to amateur astronomers.

²⁰ George F. Chambers, Descriptive Astronomy (Oxford, 1867), pp. 473–4.

²¹ John Herschel, ‘Subsidiary Tables for Facilitating the Computation of Annual Tables of the Apparent Places of Forty-Six Principal Fixed Stars …’, Memoirs of the Astronomical Society of London, 1 (1825), 421–96 (p. 431).

²² See chapter 2, ‘Of the Nature of astronomical Instruments and Observations in general …’, in John Herschel, A Treatise on Astronomy (Philadelphia, 1834), pp. 66–105.

²³ Dewhirst equates the practice of positional astronomy with the idea of a physical observatory by noting that looking up the word ‘Observatory’ in the 1843 Penny Cyclopedia one is told to see ‘Transit instrument’ (Dewhirst, ‘Meridian Astronomy’ (note 2), p. 150).

²⁴ John Herschel to William Wallace, 23 March 1825, in Royal Society Collections: Letters and Papers of Sir John Herschel (Frederick, MD, 1990), microform, 28 reels, reel 20, p. 203.

²⁵ John Herschel, ‘An Address Delivered at the Anniversary Meeting of the Astronomical Society of London, Feb. 13. 1829 …’, in Essays from the Edinburgh and Quarterly Reviews with Addresses and Other Pieces (London, 1857), p. 510.

²⁶ John Herschel to William Wallace, 23 March 1825, in Royal Society Collections: Letters and Papers of Sir John Herschel (Frederick, MD, 1990), microform, 28 reels, reel 20, p. 508.

²⁷ John Herschel to William Wallace, 23 March 1825, in Royal Society Collections: Letters and Papers of Sir John Herschel (Frederick, MD, 1990), microform, 28 reels, reel 20, pp. 512–13.

²⁸ John Herschel to William Wallace, 23 March 1825, in Royal Society Collections: Letters and Papers of Sir John Herschel (Frederick, MD, 1990), microform, 28 reels, reel 20, p. 512.

²⁹ George Airy, ‘Report on the Progress of Astronomy during the Present Century’, in Report of the First and Second Meetings of the British Association for the Advancement of Science (London, 1833), pp. 125–89.

³⁰ John Herschel, ‘An Address Delivered … on the Occasion of the Delivery of the Honorary Medals of that Society, on Feb. 8. 1828 …’, in Essays from the Edinburgh and Quarterly Reviews (London, 1857), pp. 491–2.

³¹ John Herschel, ‘Account of Some Observations Made with a 20–feet Reflecting Telescope …’, Memoirs of the Astronomical Society of London, 2 (1826), 459–97 (p. 463).

³² For the production of the Brisbane Catalogue and more information about Parramatta Observatory, see Simon Schaffer, ‘Keeping the Books at Parramatta Observatory’, in Heavens on Earth (note 2), pp. 118–47.

³³ John Herschel to Thomas Maclear, between 5 and 23 March 1836, in Brian Warner and Nancy Warner, Maclear & Herschel: Letters & Diaries at the Cape of Good Hope 1834–1838 (Cape Town, 1984), p. 135.

³⁴ John Herschel to Thomas Maclear, c. 15 February 1837, in John Herschel to Thomas Maclear, between 5 and 23 March 1836, in Brian Warner and Nancy Warner, Maclear & Herschel: Letters & Diaries at the Cape of Good Hope 1834–1838 (Cape Town, 1984), p. 164.

³⁵ John Herschel to George Gipps, 26 December 1837, in Letters and Papers of Sir John Herschel (note 24), reel 19, p. 72.

³⁶ ‘Lacaille, Nicolas-Louis De’, Complete Dictionary of Scientific Biography, edited by C.C. Gillispie, vol 7, pp. 542–5, and William Tobin, ‘La Caille and the Far Southern Sky’, Southern Stars: Journal of the Royal Astronomical Society of New Zealand, 52 (2013), 3–15.

³⁷ John Herschel, ‘Preface’, in A Catalogue of 9766 Stars in the Southern Hemisphere, for the Beginning of the Year 1750 from the Observations of the Abbe de Lacaille…. (London, 1847), p. iii.

³⁸ Herschel, Treatise on Astronomy (note 22), §252.

³⁹ Herschel, Treatise on Astronomy (note 22), §252.

⁴⁰ John Herschel to Thomas Maclear, 21 February 1836, in Warner and Warner, Maclear & Herschel (note 33), pp. 126–7.

⁴¹ Thomas Maclear to John Herschel, 23 February 1836, in Warner and Warner, Maclear & Herschel (note 33), pp. 128–9.

⁴² Thomas Maclear to John Herschel, 4 March 1836, in Thomas Maclear to John Herschel, 23 February 1836, in Warner and Warner, Maclear & Herschel (note 33), p. 130.

⁴³ William Whewell to Mary Somerville, 29 August 1838, in Mrs Stair Douglas, The Life and Selections from the Correspondence of William Whewell (London, 1882), p. 194.

⁴⁴ John Herschel to Thomas Maclear, 13 December 1837, in Warner and Warner, Maclear & Herschel (note 33), pp. 205–7.

⁴⁵ John Herschel to Thomas Maclear, 13 December 1837, in Warner and Warner, Maclear & Herschel (note 33), pp. 205–6. By ‘Classes of men’, Herschel likely meant non-specific identifiers such as ‘the King’, ‘the Warrior’, etc., though he did not offer examples. He implied that such generalizations would allow different nationalities to unofficially represent whomever they chose in such positions. He also did not offer any examples of what he meant by ‘recognized Classical assemblages’, though he may have only wished to extend the classification that already included the well-known Hyades and Pleiades.

⁴⁶ John Herschel 1838 diary, 8 April 1838, in Letters and Papers of Sir John Herschel (note 24), reel 28, transcribed by David R. Dyck.

⁴⁷ John Herschel, ‘On the Advantages to Be Attained by a Revision and Re-arrangement of the Constellations …’, Memoirs of the Royal Astronomical Society, 12 (1842), 201–24 (p. 206).

⁴⁸ John Herschel, ‘On the Advantages to Be Attained by a Revision and Re-arrangement of the Constellations …’, Memoirs of the Royal Astronomical Society, 12 (1842), 201–24, p. 206.

⁴⁹ John Herschel, ‘On the Advantages to Be Attained by a Revision and Re-arrangement of the Constellations …’, Memoirs of the Royal Astronomical Society, 12 (1842), 201–24, pp. 213–7.

⁵⁰ Herschel diaries, 11 January 1840, 13 March 1843, 23 March 1843, 11 May 1843, and 2 June 1843, in Letters and Papers of Sir John Herschel (note 24), reel 28, transcribed by David R. Dyck. [Herschel], ‘Report of the Committee … for Revising the Nomenclature of the Stars’, British Association for the Advancement of Science Report for 1843 (1844), p. 292.

⁵¹ John Herschel, ‘Further Remarks on the Revision of the Southern Constellations’, Monthly Notices of the Royal Astronomical Society, 6 (1844), 60–2.

⁵² Besides the catalogue of Lacaille, which has been referenced above, the other two catalogues were published as Francis Baily, The Catalogue of Stars of the British Association of the Advancement of Science Containing the Mean Right Ascension and North Polar Distances of Eight Thousand Three Hundred and Seventy-Seven Fixed Stars, Reduced to January 1, 1850 (London, 1845) and Francis Baily, A Catalogue of Those Stars in the Historie Céleste Française of Jérôme Delalande, for Which Tables of Reduction to the Epoch 1800 have been Published by Professor Schumacher (London, 1847).

⁵³ John Herschel, ‘Report of a Committee … for Revising the Nomenclature of the Stars’, British Association for the Advancement of Science Report for 1844, part 1 (1845), 32–42.

⁵⁴ Bolt, ‘Herschel's Natural Philosophy’ (note 9), p. 10.

⁵⁵ John Herschel, A Preliminary Discourse on the Study of Natural Philosophy (Chicago, 1987 [1830]), §310.

⁵⁶ John Herschel, A Preliminary Discourse on the Study of Natural Philosophy (Chicago, 1987 [1830]), §310, §311.

⁵⁷ For example, in his letter to Governor Gipps on the potential uses of the Parramatta Observatory, Herschel devoted two full pages to the type of physical observations that the observatory should regularly make. John Herschel to George Gipps, 26 December 1837, in Letters and Papers of Sir John Herschel (note 24), reel 19, p. 72.

⁵⁸ John Herschel, ‘[Review of] 1. History of the Inductive Sciences … ‘, Quarterly Review, 68 (1841), 237, reprinted as ‘Whewell on the Inductive Sciences’, in Essays from the Edinburgh and Quarterly Reviews (note 25), quote on pp. 253–4.

⁵⁹ John Herschel, ‘An Address to the British Association for the Advancement of Science …’, in Essays from the Edinburgh and Quarterly Reviews (note 25), pp. 651–2.

⁶⁰ Francis Bacon, The New Organon, in The Works of Francis Bacon, edited by James Spedding, Robert Leslie Ellis, and Douglas Denon Heath, 15 Vols (Boston, 1863), vol 8, §1.82.