Biographies & Memoirs


Herschel on the Moon


Shortly after his election as President of the Royal Society in 1778, Joseph Banks began to hear rumours of an unusually gifted amateur astronomer working away on his own in the West Country. These rumours first reached him through the Society’s official Secretary, Sir William Watson, whose brilliant and unconventional son, a young physician based in Somerset, was a moving spirit behind the newly founded Bath Philosophical Society. Watson (junior) began sending accounts to his father of a strange maverick who owned enormously powerful telescopes (supposedly built by himself), and was making extravagant claims about the moon.

The initial reports that reached Banks were strange and somewhat sketchy. The man was called Wilhelm Hershell or William Herschel, possibly a German Jew from Dresden or Hanover.1 One winter night in 1779 young Watson had found this Herschel in Bath, standing alone in a cobbled backstreet, viewing the moon through a large telescope. Though tall and well-dressed, and wearing his hair powdered, he was clearly an eccentric. He spoke with a strong German accent, and had no manservant accompanying him. Watson asked if he might take a look through the instrument, which he noticed was a reflector telescope, not the usual refractor used by amateurs. It was large-seven feet long-and mounted on an ingenious folding wooden frame. The whole thing was evidently home-made. To his surprise he found its resolution was better than any other telescope he had ever used. He had never seen the moon so clearly.2

They fell into slightly halting conversation. Watson was immediately taken by Herschel’s humorous and modest manner, and soon realised that it disguised an acute unconventional intelligence. Herschel’s knowledge of astronomy, though obviously self-taught, was impressive. Though he had no university education, and said he had very little mathematics, he had mastered John Flamsteed’s great atlas of the constellations, read the textbooks of Robert Smith and James Ferguson, and knew a great deal about French astronomy. Above all he knew about the construction of telescopes, and the making of specula-mirrors. Though in his early forties, he talked of the stars with a quick, boyish enthusiasm, that betrayed intense and almost unnerving passion. Watson was so struck that he asked if he might call round to see him the very next morning.

The house at 19 Rivers Street, in the lower, unfashionable section of Bath, was modest, and clearly Herschel was not a gentleman of leisure. The lower rooms were cluttered with astronomical equipment, but the front parlour was dominated by a harpsichord and piled high with musical scores.3 It emerged that Herschel was a professional musician, held the post of organist at the Bath Octagon Chapel, and made ends meet by giving music lessons. He also composed, and was fascinated by the theory of musical harmony. His domestic situation was odd. He was poor, and unmarried, but Watson noticed that he spoke tenderly of a sister, who was not only his housekeeper but also his ‘astronomical assistant’.4

Watson invited his new acquaintance to join the Bath Philosophical Society. Herschel responded with alacrity. Though hesitant to speak in public, he started submitting papers through Watson. Many of them were strange ventures into speculative cosmology and the philosophy of science. They included such subjects as ‘What becomes of Light?’, ‘On the Electrical Fluid’ and ‘On the Existence of Space’.5

Proud of his new discovery, Watson sent what he considered the best of these early papers to his father, Sir William, at the Royal Society in London. Herschel was modestly worried that his English would not be up to the mark, and Watson tactfully corrected each paper. It was not their plain literary style, however, which caused controversy, but their content. The very first of them, ‘Observations on the Mountains of the Moon’, was so unconventional that it caused an unaccustomed stir when it was published in the Society’s august journal Philosophical Transactions in spring 1780. In it Herschel claimed that with his home-made telescopes he had observed ‘forests’ on the lunar surface, and that the moon was ‘in all probability’ inhabited.

Nevil Maskelyne, the Astronomer Royal and leading cosmological light of the Royal Society, was more than a little outraged by these apparently absurd claims. He had himself established that the moon had no life-sustaining atmosphere, based on the sharpness with which it occults starlight at its edge.6 But he was intrigued by the minute detail of Herschel’s observational sketches of the moon’s surface, and the apparently fantastic power of his reflector telescope. He wrote a challenging letter to Watson in Bath, questioning the seriousness of Herschel’s work, and his views on the moon. It was now that Joseph Banks, always on the lookout for new and unusual scientific talent, began to pay attention.

Watson forwarded what he tactfully called ‘Dr Maskelyne’s extremely obliging letter’ to Herschel. Clearly anxious that Herschel might take offence at the implied criticism, he urged a diplomatic response in a covering note of 5 June 1780: ‘I think you would do right (pardon my giving you advice) either to add the desired improvements, or to write over again the Paper, and send it to Dr Maskelyne, who, as he is Astronomer Royal, will be pleased, I believe, with the compliment paid him, and he will present it anew to the Society.’7

To his relief, Herschel wrote back to the Astronomer Royal with apparent modesty on 12 June: ‘I beg leave to observe Sir, that my saying that there is an absolute certainty of the Moon’s being inhabited, may perhaps be ascribed to a certain Enthusiasm which an observer, but young in the Science of Astronomy, can hardly divest himself of when he sees such Wonders before him. And if you promise not to call me a Lunatic I will transcribe a passage from some observations begun 18 months ago, which will show my real sentiments on the subject.’8

The views that Herschel now expressed must have taken Maskelyne aback. Far from retracting his opinions, he emphasised his belief that ‘from analogy’ with the earth, and its likely conditions of heat, light and soil, the moon was ‘beyond doubt’ inhabited by life ‘of some kind or other’. Even more provocatively, he thought that the terrestrial view of matters gave undue importance to the earth. ‘When we call the Earth by way of distinction a planet and the Moon a satellite, we should consider whether we do not, in a certain sense, mistake the matter. Perhaps-and not unlikely-the Moon is the planet and the Earth the satellite! Are we not a larger moon to the Moon, than she is to us?…What a glorious view of the heavens from the Moon! How beautifully diversified with [her] hills and valleys!…Do not all the elements seem at war here, when we compare the earth with the Moon?’

That Herschel was writing somewhat mischievously to the Astronomer Royal becomes clear towards the end of his letter. Poetry gently creeps up on astronomy: ‘The Earth acts the part of a Carriage, a heavenly waggon to carry about the more delicate Moon, to whom it is destined to give a glorious light in the absence of the Sun. Whereas we, as it were, travel on foot and have but a small lamp to give us light in our dark nights, and that too often extinguished by clouds.’ The teasing wit in Herschel’s final sally was unmistakeable: ‘For my part, were I to choose between the Earth and the Moon, I should not hesitate a moment to fix upon the Moon for my habitation!’9

Maskelyne could not overlook this, and promptly visited Herschel in Bath, accompanied by Banks’s new Secretary and confidant at the Royal Society, Dr Charles Blagden. The visit seems to have been somewhat stormy. They cross-questioned Herschel in a challenging manner, but reported back to Banks that they were strangely impressed, especially by Herschel’s beautiful home-made telescopes, of which there were several. There was also the unusual matter of the sister, a small, shy, tongue-tied young woman who seemed as mad about astronomy as her brother. Her name was Caroline. There was however no reason to believe that the Herschels would achieve anything particularly original in astronomy. They were provincials, émigrés, and poor self-taught enthusiasts.

Unknown to Maskelyne, the tongue-tied Caroline Herschel had made her own brief note of this visitation from the great men of the metropolis. The ‘long conversation’ which Dr Maskelyne held with her brother William got nowhere, and to her ‘sounded more like quarrelling’. Immediately Dr Maskelyne left the house her brother burst out laughing and exclaimed: ‘That is a devil of a fellow!’10

Less than a year later, in March 1781, Banks was amazed to hear that William Herschel was about to revolutionise the entire world of Western astronomy. He had achieved-or possibly achieved-something that had not been done since the days of Pythagoras and the Ancient Greek astronomers. Herschel had discovered what was perhaps a new planet. If so, he had changed not only the solar system, but revolutionised the way men of science thought about its stability and creation.


William Herschel was born in Hanover on 15 November 1738, and his younger sister Caroline twelve years later, on 16 March 1750. Their passion for observational astronomy came absolutely to rule both their lives, although in very different ways. At its height, in the 1780s, brother and sister spent night after night, month after month, summer and especially winter, alone but together in the open air, under a changing canopy of stars and planets. Their minutely recorded telescope observations, published in over a hundred papers by the Royal Society, would change not only the public conception of the solar system, but of the whole Milky Way galaxy and the structure and meaning of the universe itself.

Herschel and his sister were deeply attached from childhood, and most of what is known about William’s life is drawn from Caroline’s affectionate but troubled journal or day book, which she later turned into a memoir. She once wrote: ‘If I should leave off making memorandums of such events as affect, or are interesting to me, I should feel like-what I am, namely, a person that has nothing more to do in this world.’11 

William was well into his thirties when astronomy began to take over his existence. The Herschel family concern over several generations had been music, not stargazing. In mid-eighteenth-century Germany-then a series of city states-the profession of music-playing, singing, composing, and teaching-was as socially important as those of the law, the army or the Church. Each city court and most military regiments had their own orchestras, and those of Hanover had some of the most renowned in Europe. Their fame spread especially after the Elector of Hanover became George I of England in 1715, and composers such as Handel achieved Europe-wide status.

William and Caroline’s father, Isaac, was a military bandsman with the Hanover Foot Guards. His own father had been a landscape gardener near Magdeburg in Saxony who had an amateur interest in the oboe, but who died when Isaac was only eleven. Isaac, virtually an orphan, and without proper education, also began life as a gardener on various aristocratic Prussian estates. But at twenty-one, in his own words, he ‘lost all interest in horticulture’, found he had a natural ear for music, and ‘worked day and night to become an oboe player’. Despite advice from his elder brother to stick to gardening, he could ‘no longer resist the desire to make music and to travel’, and drifted first to Potsdam, then to Brunswick (’too Prussian for me’), and finally to Hanover, where the atmosphere was more liberal.12 The Elector of Hanover was now George II of England, and more easy-going English manners were acceptable. In August 1831 Isaac joined the Hanover military band, a happy career choice which allowed him considerable freedom, until he was caught up in the Anglo-German campaigns against the French which swept mid-eighteenth-century Europe.13

At twenty-five Isaac fell in love with a local girl, Anna Moritzen, who came from a village just outside Hanover. She was a beautiful creature, but completely illiterate. They might not have married except that Anna got pregnant, and Isaac proved himself a man of honour. Anna later said prettily that Isaac dropped into her life ‘as if from a cloud’.14 They steadily produced one child every two years for the next twenty years-but though ten children were born only six survived, a cause of much grief. Anna adored her first-born, Jacob, above all else, and indulged him extravagantly; she also loved her first daughter, Sophie, the beauty of the family. With the remaining children she was more severe, especially with her youngest and least promising daughter, Caroline.

Anna always seemed to be struggling to control the large, unruly family during Isaac’s frequent absences with his regiment. She tried to inculcate traditional German virtues: discipline, craftsmanship, thrift and family loyalty. She had no patience with ‘book-learning’, especially as far as her daughters were concerned. However, she accepted Isaac’s ambition ‘to make all his sons complete musicians’, which she saw as a path to fame and money. One of William’s earliest memories was of being given a tiny violin which his father had made for him, and being taught to play almost before he could hold it to his shoulder.15

Jacob was quickly established as ‘the genius’ of the family: a superb solo musician from childhood, handsome but vain and volatile, having the true ‘artistic temperament’. William was quieter and steadier, more determined in his lessons, thoughtful and genial, a great reader. Caroline mostly remembered her mother’s severity, and how her eldest brother and sister, Jacob and Sophie, were by contrast petted and indulged.

Possibly Isaac also found his wife Anna a little ‘too Prussian’. There was something dreamy, almost unworldly, about Isaac Herschel. Alongside his music-making, it is evident that he had a certain metaphysical approach to the world. He had little formal education, but for that very reason his interests were wide and passionately pursued: they included instrument-making, reading philosophy and practising amateur astronomy. It was a combination very characteristic of the culture of Enlightenment Germany, at a time when its greatest philosopher, the young Immanuel Kant, was also a craftsman and lens-grinder. Isaac was a natural teacher, patient and good-humoured; while Anna was quick-tempered, opinionated and scornful of what she regarded as bookishness.

Caroline remembered her father taking her out into the street to see the winter stars on a clear, frosty night, ‘to make me acquainted with the most beautiful constellations, after we had been gazing at a comet which was then visible’.16 Perhaps this stayed in her mind, because finding comets would later become her particular passion. She also recalled being shown an eclipse of the sun, safely viewing it reflected in a bucket of water.17 She added admiringly that her father loved helping William with his studies, and was particularly delighted with his ‘various contrivances’-by which she meant his scientific models. (Her phrasing, like her accent, remained pleasingly Germanic to the end of her life.) Among these she particularly remembered a shining, neatly turned four-inch brass globe, ‘upon which the equator and ecliptic were engraved by my brother’, an object of childish wonder and admiration to her. This was an early sign of William’s extraordinary manual skills, which she came to worship.18 Her own secret desire was to become a concert singer, but she dared tell no one about this except William.


Perhaps the moments of paternal care were remembered because they were rare. Isaac was often away on campaign, and Anna ran the noisy, chaotic household as the growing family moved from apartment to apartment in Hanover, depending on their financial circumstances. There was great sibling rivalry. The bond between William and Caroline was strengthened by their vain and bullying brother Jacob, who as his mother’s darling had become spoilt and domineering. There was also the unhappy elder sister Sophie, whose beauty led to an early marriage with a ‘cruel and extravagant’ husband which turned out to be a disaster.19 Caroline-who was small and impish-claimed she was frequently whipped for disobedience both by her mother and by Jacob, starved for food, and treated as a scullion. Similarly, she said William had been endlessly teased by Jacob for his outstanding work at the garrison school in Latin, Greek, French and mathematics. He also mocked his model-making abilities. Jacob took nothing seriously but ‘the science of music’, in which he already considered himself (rightly) a virtuoso.20

At fourteen William joined the Hanover regimental band, alongside Jacob and his father. He soon learned to turn his hand to an astonishing array of instruments-the oboe, the violin, the harpsichord, the guitar and, a little later, the organ. He was also starting to compose, and had an early fascination with musical notation and the theory of harmony. Both he and Jacob appeared as young solo performers at the court of the Elector of Hanover, and their names were not forgotten.

Caroline also remembered long philosophical arguments at home in the evenings, when the brothers returned after concerts. She would lie awake in her bedroom, trying not to fall asleep and secretly delighting in William’s quiet, calm voice steadily contradicting Jacob’s furious outbursts. According to her the names of ‘Leibniz and Newton’ were shouted from the parlour ‘with such warmth that my Mother’s interference became necessary’.21 When their father was at home these conversations on philosophical subjects became even more rowdy, and would frequently last till dawn. The combination of Leibniz and Newton suggests that William and Jacob were arguing about the rival virtues of calculus (a mathematical system invented by Leibniz) and fluxions (a similar system invented-but jealously guarded-by Newton). Both systems produced the new mathematics of curves and gradients, essential to the astronomical calculation of planetary orbits and the elongated ellipses of comets. It was an unusual household.22

In November 1755 the five-year-old Caroline witnessed a strange portent of disruption in the after-shock of the Lisbon earthquake, which amazingly travelled as far as Germany. As she remembered it, the whole barracks shook. ‘I saw both my parents standing aghast and speechless…my brothers came running in…all [the family] being panic-struck by the earth quake.’23 This earthquake, which killed over 30,000 people in Lisbon and shook cities throughout Europe, seemed to many to call into question the idea of God (or Nature) as a benevolent Providence, and to be a sign that a new kind of scientific knowledge was required. Among many speculative works, it inspired Voltaire’s Candide. Caroline always retained a superstitious horror of earthquakes, and said she felt one years later when she stood by her father’s deathbed.24

In the spring of 1756, when William was seventeen and Caroline was six, the Hanover Foot Guards were posted to England, to serve under their ally the Hanoverian King George II. It was the outbreak of a long, desultory and financially draining conflict with the French that would become the Seven Years War, and would radically affect the fortunes of the Herschel family. Jacob tried to obtain a home posting with the court orchestra, but failed, and all the men of the family were conscripted. Caroline remembered the grim, silent bustle in the house. ‘My dear father was thin and pale, and my brother William almost equally so, for he was of a delicate constitution and just then growing very fast. Of my brother Jacob I only remember his [making] difficulties at everything that was done for him.’ The rest of the family, the three younger children including the baby Dietrich, were abruptly left on their own as the men departed.

Caroline’s sense of this human drama is well caught in her Memoir. ‘The troops hallooed and roared in the streets, the drums beat louder…and in a moment they were all gone. I found myself now with my Mother alone in a room all in confusion, in one corner of which my little brother Dietrich lay in his cradle; my tears flowed like my Mother’s but neither of us could speak.’ Then Caroline made a touching gesture towards the mother she feared. She ran and found one of her father’s large cambric handkerchiefs, unfolded it, and carefully placed one corner in her weeping mother’s hand, while holding onto the opposite corner herself. They were united, at least, in grief. ‘This little action actually grew a momentary smile into her face.’25

The Hanover Regiment were stationed at Maidstone, in Kent. Jacob spent his pay on fashionable English clothes, William on English books, and Isaac on an allowance for Anna and the children. William fell in love with the country, began to learn the language, and made a small circle of English friends. For the first time there are hints that he was secretly beginning to dream of an entirely different, freer kind of life in the land of Newton, which had been adopted by his fellow German Handel. When the Hanover Guards were posted back to Germany the following spring to fight the invading French armies, Jacob packed a beautifully tailored English suit, and William a copy of John Locke’s Essay Concerning Human Understanding.26

Caroline remembered their return, one freezing winter evening in December 1756.27 Her mother Anna was preparing a welcome-home dinner, and the six-year-old Caroline was sent to collect her father and brothers from the parade ground. But she missed them in the dark and confusion, and the frightened little girl had to make her own way home. ‘I continued my search till I was spent with cold and fatigue, and on coming home I found them all at table, nobody greeting me but my brother.’ As she remembered it, no one had even noticed her absence except William. She never forgot his reaction. ‘My dear brother William threw down his knife and fork, and ran to welcome and crouched down to me, which made me forget all my grievances.’28

Jacob now obtained a timely discharge, but William and his father took part in the disastrous battle of Hastenbeck, which was fought against the French invaders twenty-five miles outside the city of Hanover, on 26 July 1757. The surrounding countryside was overrun by a French army of 60,000 troops under Marshal d’Estrées. The allied general, the Duke of Cumberland, beat a strategic retreat westwards towards Flanders. Hanover was occupied, and the Herschels’ building had sixteen French infantrymen billeted on it.29

After a hasty family conference it was decided to smuggle William-still only eighteen-out of Germany altogether. Caroline recalled a fleeting, romantic glimpse of her brother’s surreptitious departure as she stood anxiously by the street door, told not to call out or give him away: ‘he glided like a shadow along, wrapped in a great coat, followed by my mother with a parcel containing his accoutrements’.30 William slipped past the last sentinel at Herrenhausen, and made his way to Hamburg, where he took ship again for England. At the last moment he was joined by Jacob, and together the two brothers arrived, penniless refugees, in London. They supported themselves by copying musical scores, giving oboe lessons, and playing as freelance musicians in local orchestras. They gave a successful concert in Tunbridge Wells. In the evenings William read voraciously: English novels, books on mathematics and musical harmony, Robert Smith’s Harmonics (1749) and James Ferguson’s recently published and immensely popular Astronomy Explained (1756).31

By the autumn of 1759 Jacob was finding the life too hard, and slipped back to Hanover with his and William’s combined savings, eventually finding employment as a court musician.32 Now, for the first time in his life, William Herschel, aged twenty-one, was alone-but free, talented, and in the country of his choice. And with a secret gift, his genius for astronomy, hidden even from himself-but awaiting the opportunity to unfold. For the next five years he virtually disappeared from the family history.

Caroline was devastated when William went abroad. In retrospect, she realised that it was he alone who had cared for her, and in his long absence he became a sort of legendary figure. At home her misery deepened. Hanover remained occupied, and food supplies were short. She continued going to the garrison school, but was not allowed to learn arithmetic or languages, and was increasingly treated as a maidservant by the family. She remembered sewing immensely long woollen stockings, scrubbing laundry, and writing her mother’s letters to her father on campaign. In fact her unusual literary ability was a rare source of pride, as she later recalled. ‘My pen was taken frequently in requisition for writing not only my Mother’s letters to my Father, but to many a poor soldier’s Wife in our Neighbourhood to her Husband in the Camp; for it ought to be remembered that in the beginning of the last century very few women left country schools with having been taught to write.’33

Her father had been made a prisoner of war, and for some months her brother Jacob became effective head of the family. He ‘woefully disarranged’ the household, demanded larger rooms, and bullied his little sister. ‘Poor I got many a whipping for being too awkward at supplying the place of footman or waiter.’34 When her father finally returned from the wars in summer 1760, aged fifty-three, he was a broken man, his health permanently damaged by many months of imprisonment, asthmatic and with a heart condition.35 He gave some private music lessons, smoked his pipe, and was largely ruled by his wife and his eldest son. He did however manage to regularise William’s situation as a soldier absent without leave. On 29 March 1762 General A.F. von Sporcken signed a formal document of discharge.36 But there was no sign of their son coming home.

Caroline’s own health was bad. At the age of five she had caught smallpox, and now at eleven she caught typhus. While she was recovering her mother left her to crawl up and down stairs ‘on my hands and feet like an infant’ for several months.37 The worst result of this illness and neglect was that Caroline’s growth was permanently stunted. In a family of tall, lean children, she never grew much beyond five feet.38 Moreover, her face had been permanently scarred by the smallpox. The lively, enchanting pixie that William had once known had become a silent, resentful gnome. But she also became increasingly determined and self-sufficient. She said that from the time of her recovery, ‘I do not remember ever having spent a whole day in bed.’39

Isaac increasingly left the care of his surviving children largely in Jacob’s hands: Alexander aged seventeen, Caroline aged twelve, and the youngest, Dietrich, a sweet but sickly child, aged seven. Her father would indulge Caroline (‘and please himself’) with a short lesson on the violin, but he told her mournfully that as she was now ‘neither handsome nor rich’ she could never expect to marry, and should resign herself to helping her aged parents.40

Her brother Jacob refused to allow her to train as a milliner, although she was encouraged to learn just enough to be able to deal with the household clothes and linen. Her father had once hoped to give her ‘something like a polished education’, but her mother insisted that, given the family situation, it should be practical and ‘rough’; she would not even allow her to learn French, in case she developed ambitions to be a governess.41 Similarly, little Dietrich was denied a dancing master. Anna also observed that it was ‘her certain belief’ that had William read less, he would never have stayed away in England.42 When Jacob insisted that an extra servant girl be hired, she was given Caroline’s room and bed to share. For Caroline, ‘her destiny now seemed unalterable’. She was to be the family housekeeper, a spinster and permanent maidservant.43 She later decided to destroy all the journals referring to her private feelings during these years of misery. She did not want to write in the fashionable Romantic mode of the personal confession. ‘After reading over many pages,’ she wrote to Dietrich, ‘I thought it better to destroy them, and merely write down what I remember to have passed in our family at home, and abroad.’

In fact much remains of her inner life: as much perhaps as in the journals of Dorothy Wordsworth. This dramatic rejection of the record of her childhood unhappiness was really a prelude to continuing revelations of frustrations in adulthood. ‘By what is to follow,’ she explained, ‘[Dietrich] may also see how vainly his poor Sister has been struggling through her whole life…wasting her time in the performance of such drudgeries and laborious works as her good Father never intended to see her grow up for.’ This was the ultimate cause, she came to think, of the ‘mortifications and disappointments which have attended me throughout a long life’. But all this was in retrospect, nearly sixty years later.44

In the summer of 1764, apparently without warning, to Caroline’s astonished delight her brother William-‘let me say my dearest brother’-reappeared in Hanover.45


What had happened to him in the interval? From his intermittent letters to Jacob, and things he subsequently told Caroline, it is possible to reconstruct the outline of his adventures, though with many gaps. Against all expectation, he had not remained in London, or gone back to his friends in Kent, but had boldly struck into the remote north of England. Surprisingly he used his military contacts to obtain the post of civilian music master to the Durham militia, which was stationed under the Earl of Darlington at Richmond in Yorkshire.46 This was as much a social engagement as a military one, and Herschel was soon completely independent, working as a freelance musician and music teacher in Leeds, Newcastle, Doncaster and Pontefract, and as an organist in Halifax. Little is known about these posts, except that he was constantly on the move, frequently lonely, and sometimes weeping with homesickness.

Every so often Jacob received letters from William with varied English postmarks, and written-with remarkable versatility-in German, French or English as the mood and subject took him. These letters were also covered in mechanical diagrams, and frequently shifted without a break from words to musical notation. They give a sense of Herschel’s mind switching with extraordinary agility between different modes of expression and zones of thought-literary, mechanical, musical, philosophical.47

From Yorkshire on 11 March 1761 he wrote in a fit of melancholy for which he chose slightly faltering English: ‘I must tell you a certain anxiety attends a vagrant life. I do daily meet with vexations and trouble and live only by hope. Many a restless night have I had; many a sigh and-I will not be ashamed to say it-many a tear.’ But a fortnight later he was writing from Sunderland in sprightly French about two pretty girls he had just met-one of them ‘la plus belle du monde, la Beauté elle-meme personnifée’-whose accomplishments included excessive blushing, flirting and playing the guitar. Sadly they only met once, though Herschel later confessed that they corresponded for over a year-another indication of his loneliness, perhaps.48

He chose German for his philosophical reflections. All of these were thoughtful, but many of them gloomy: the stoic doctrines of Epictetus, the optimism of Leibniz (’not the least credible nor feasible’), the origins of evil, the nature of sin, the ethical (rather than the intellectual) necessity for Christian religion in European society. ‘In all ages there have been philosophers who have had thoughts above their religion, and have been true Deists’-but it was ‘impossible’ in the present state of education for ‘a whole nation to be true Deists’. William himself described God memorably, in German, as ‘the unknowable, must-exist Being’.49 With this formula he was able to set aside, for the time being at least, the problem of a personal Creator.

He had thought often about the ‘immortality of the soul’, but said (to Jacob at least) that he preferred not to draw any conclusions. His unchar-acteristically pious explanation seems to disguise a scientific reservation that there was no ‘intelligible’ data on the matter: ‘My feeble understanding is not capable of pushing so far into the secrets of the Almighty; and as all those propositions have something unintelligible about them, I think it better to remain content with my ignorance till it pleases the Creator of all things to call me to Himself and to draw away the thick curtain which now hangs before our eyes.’ In fact ‘pushing far into secrets’ was always Herschel’s natural instinct and delight.50 Perhaps music provided a way of pondering these questions, and at this time he composed an oratorio based on Milton’s Paradise Lost, though the manuscript score has not survived.51

Another way would be astronomy. For the glowing exception to these dark truths about human life was always the life of Nature, already an endless source of clarity and consolation for Herschel. ‘If one observes the whole Natural World as one, one finds everything in the most Beautiful Order; it is my favourite maxim: Tout est dans l’ordre!52

Riding between musical engagements, from one remote provincial northern town to another, often crossing over the moors alone at night, he found himself studying the panoply of stars overhead as he had done as a boy. He became well acquainted with the moon, and would later write that at this time he had intended ‘to fix upon the moon for my habitation’.53 He also later told several tales about these lonely rides, one being how on one occasion he was reading so intently that when his horse stumbled and threw him, he somersaulted over its head and landed upright still holding his book in his hand, a perfect demonstration of the Newtonian law of ‘circular motion’.54

Herschel now began to explore further the work of James Ferguson (1710-76), a man after his own heart who had started life as an illiterate Highland farm-labourer, and had become one of the most distinguished practical astronomers and demonstrators. His Astronomy Explained (1756) ran to numerous popular editions, and he later vividly described in his Autobiography (1773) how he fell in love with astronomy. He would take a blanket out into the fields after work, and lie on his back measuring star distances and patterns with beads on a string held up over his head. He then transferred these, by the light of a stub of candle on a stone, to his first paper star-maps, spread out beside him on the grass. He said he imagined the ecliptic (the sun’s curving path through the heavens) like a high road running through the stars. Gradually he taught himself astronomy and built his own telescopes. He later invented various devices for projecting constellations during his lectures, and his ‘Eclipseon’ for showing the various movements of the solar system.

Living in lonely bachelor lodgings, Herschel spent more and more time reading about stellar theory. He followed Robert Smith’s Harmonics (1749) with his Compleat System of Opticks (1738), which contained illustrated sections on astronomical observations.55 He began to be preoccupied with various cosmological problems: what was the relation between music, mathematics and star patterns? Was there life on the moon? What was the structure and composition of the sun? How far away were the nearest stars? What was the true size and shape of the Milky Way? Many of these problems would emerge in his earliest scientific papers, and would continue to fascinate him for the rest of his life.

He was approaching thirty, and to all appearances he was alone and adrift in a foreign land. But he was not disorganised or depressed. Much of his father’s military discipline, and his own professionalism, now stood him in good stead. He worked immensely hard, with an energy and determination that never left him. His musical appointments were increasingly important, regular and better paid. At Halifax he was conducting an orchestra, playing the organ, giving singing lessons, and composing his own music. He was also learning Italian.

After a period of physical weakness in his late teens (which Caroline had anxiously remarked on), William had grown into a tall, commanding figure, with a high, intellectual forehead, and very striking dark eyes. Outwardly at least, he was cheerful and sociable. It is evident that he made friends wherever he went. At one concert he was joined by the Duke of York, brother of the new King George III, who accompanied him (rather badly) on the violoncello. On another occasion he was invited to conduct one of his own symphonies at St Cecilia’s Hall in Edinburgh. At the reception afterwards, he chanced to meet the philosopher David Hume, and was promptly invited out to dinner.56 There was something about Herschel’s mixture of intensity and innocence that simply charmed people. And talented German exiles were, of course, popular.

Herschel was brought back to Hanover by a combination of circumstances. His work at Halifax had led to the first really serious opportunity of his career: the possibility of being appointed the organist of the new Octagon Chapel at Bath, when its building was completed. Bath was fast becoming the most fashionable city in England-nearly ready for Beau Brummell-and all kinds of other musical work would obviously be available there. Herschel immediately thought of his brothers, Jacob and Alexander. He had heard too that his father Isaac was ill, and not likely to live much longer. There may also have been worries about the younger children under Jacob’s care-Caroline and little Dietrich.57 At all events, the prodigal son suddenly reappeared in Hanover in the summer of 1764. He arrived saying he had just observed an eclipse of the sun as he rode over the Luneburger Heath.

Caroline was then fourteen, and her appearance following her illness must have shocked him. But there was little that he could do for her immediately, and after an absence of nearly seven years his visit to Hanover lasted a mere fortnight. It was a sober reunion. Isaac, obviously failing, could not persuade him to remain, and instead William spoke of future plans for his brothers as musicians in England. Nothing was said of Caroline at this point. William must have known it was the last time he would see his father alive.

Caroline remembered William’s departure after his flying visit with grief and frustration. It was the day of her first communion, and William had particularly admired her appearance in a new black silk dress. But she was sent to church by Jacob, and not allowed to see William off. She never forgot that moment. ‘The church was crowded and the door open. The Hamburg Postwagen passed at eleven, bearing away my dear brother…It was within a dozen yards from the open door; the postillion giving a smettering blast on his horn. Its effect on my shattered nerves, I will not attempt to describe, nor what I felt for days and weeks after.’ She walked home alone, ‘in feverish wretchedness’, wearing her new dress and painfully aware that she was carrying the bouquet of artificial flowers that her elder sister Sophia had worn on her ill-fated wedding day.58

Their father died of a stroke in 1767, but William did not return for the funeral. He would not come back to Hanover for another eight years.59


William was offered the organ post in August 1766, and officially moved to Bath in December of that year. Before the chapel was opened he found a lucrative position in the famous Pump Room Band, run by the impresario James Linley. The Pump Room and Theatre was then the very height of fashionable entertainment. Linley’s daughter, the singer ‘Angel’ Linley, later became a star at Drury Lane, and married the dramatist Richard Brinsley Sheridan.

Early on, Herschel had a quarrel with Linley over orchestral arrangements in the Pump Room, which got into the newspapers and caused a brief but diverting scandal in Bath society. The disagreements were minor-the appointment of singers, the provision of music stands-but there was some suggestion that Linley was exploiting Herschel as a German outsider. What was remarkable was the sudden revelation of Herschel’s fiery temper and determination when roused. Far from conceding to Linley, he took out a series of advertisements against his concerts in the Bath Chronicle. He referred openly to Linley’s ‘low Cunning and dark Envy’, and set up a competing programme with a rival diva, the Italian singer Signora Farinelli. This proved a great success.

After one season of musical warfare Linley made peace with Herschel, and their combined concerts resumed at the Pump Room, to general satisfaction. After Linley left for London, Herschel became sole director. Moreover Linley became a great admirer of Herschel, and sent his son Ozias to him to learn the violin. It was perhaps no coincidence that when Ozias went on to Oxford, he studied mathematics and astronomy.60

William rented a modest house ten minutes’ walk from the Pump Room, in the upper part of Bath, at Rivers Street. He continued composing for the oboe, taught guitar, harpsichord and violin, conducted oratorios and gave singing lessons. In June 1767 he was joined by Jacob for a visit, and took up his appointment as organist and choirmaster at the Octagon Chapel, which was opened on 4 October.61

It was during this hectic period that his other secret passion exerted itself. In February 1766 the twenty-seven-year-old William Herschel started his first Astronomical Observation Journal. He recorded an eclipse of the moon, and the hazy appearance of Venus.62 Hard as he worked as a musician, he was now steadily training himself as an astronomer. He devoured books on astronomical calculation, Flamsteed’s star tables and Thomas Wright’s cosmological speculations. He attended James Ferguson’s astronomy lectures at the Pump Room in 1767, and at last met this early astronomical hero of his.63 He spent hours star-gazing in the little Rivers Street garden at night. Even when teaching his music pupils in the evening, it was said that he sometimes broke off and took them outside to look at the moon. He began to build up a small arsenal of second-hand refractor telescopes, and carefully examined their construction. He was considering what his father Isaac used to call ‘one of his contrivances’.

The refractor is the classic type of straight-through telescope originally developed by Galileo, and refined by Kepler and the great seventeenth-century Dutch astronomer Christiaan Huygens. It has magnifying lenses at each end of the tube, one fixed and the other adjustable (the eyepiece), advancing or retreating to focus the image. In extendible or retractable form, it was often used by soldiers or sailors on active service, until the arrival of the binoculars. It was just such a refractor telescope that Nelson would-or would not-put to his blind eye at the battle of Copenhagen in 1798. The snapping closed of the retractable mechanism became a gesture of decision and command.

Herschel found that most refractor telescopes were satisfactory for simple low-magnification viewing of the moon or the planets. But astronomical versions were absurdly cumbersome (some up to twenty-five foot long), and almost useless for high-magnification observation of the stars. The curve or bulge in the magnifying lens acted like a prism, and broke up the white stellar light into distorting rainbow-coloured fringes at the edges. (This became known as ‘chromatic aberration’. A shortsighted person can see these rainbow aberrations of starlight with the naked eye, because his pupil is also distorted at the edges.) Newton, observing this in his famous prism experiments at Cambridge, had invented an entirely different type of telescope, the reflector. But his, which he donated to the Royal Society, was only six inches long, with a magnifying power of forty.64

Confined to refractors, most eighteenth-century British astronomers had paid little attention to stellar astronomy, except where it served for navigation purposes. (The John Dolland achromatic telescope, which corrected some prismatic distortion, was only invented in 1758, and did not come into general use-as improved by his son Peter Dolland-until the turn of the century.65) The newly appointed Astronomer Royal, Nevil Maskelyne, based at the Greenwich Observatory, was largely concerned at this time with observing lunar eclipses, planetary transits and passing comets. His special interests lay in establishing tables for use at sea as a mariner’s almanac, and in the calculation of longitude. He noted that since his seventeenth-century predecessor at Greenwich, John Flamsteed, had thoroughly mapped the heavens, he himself kept only thirty-one stars under regular observation.66

Since his long nights of riding over the moors, Herschel’s interests had roamed far beyond the safe family of the solar system, with its restricted circuit of sun, moon and six known planets. He had the courage, the wonder and the imagination of a refugee. His whole instinct was to explore, to push out, to go beyond the boundaries. Gradually he began to think about the possibilities of Newtonian reflector telescopes. Newtonians were based on a different principle from the traditional refractors. They produced increased ‘light-gathering’, rather than simple magnification. As their name implies, the primary component of a reflector telescope is a large mirror, or speculum, highly polished and subtly curved inwards (concave) so as to gather and concentrate starlight at a much greater intensity than the lens of the naked eye. This concentrated light is then viewed through a simple adjustable eyepiece inserted into the side of the tube, the whole set-up producing wonderfully bright images and little chromatic aberration.

Instead of conventional magnification, Herschel began to think in terms of something he called ‘space-penetrating power’. This was a concept he had partly developed from Robert Smith’s Opticks.67 Conventional eighteenth-century astronomers still studied the night sky as if it were a flat surface, or rather the interior surface of a decorated dome, inlaid with constellations. Flamsteed’s beautiful Celestial Atlas, first published as a large decorative folio in 1729, presented the sky like this. Its second edition of 1776 still remained the standard European book of reference for stellar identification.

Each constellation was given a double-page spread, showing the mythological figures that gave them their names drawn in flat engraved outlines, as well as the known stars belonging to the group. The brighter stars were identified by their home constellation and a Greek letter of the alphabet. So Alpha Orionis, also known by its Arabic name Betelgeuse, was the bright star on the shoulder of Orion the Hunter; and Zeta Tauri (which would later catch Herschel’s attention) was a third-magnitude star in Taurus the Bull.

But Herschel began to conceive of deep space. He began to imagine a telescope which might plunge deep down into the sky and explore it like a great unplumbed ocean of stars. This was something a reflector telescope might be able to do supremely well, if its concave mirror were sufficiently large. But because even small astronomical mirrors were expensive, and large ones had not yet been developed (even by London lens-makers like Dolland), Herschel realised that he would have to make them himself. Moreover, to achieve the exquisitely fine reflective surface he required, they would have to be cast in metal, not glass.

Meanwhile the other Herschel brothers began to shuttle between Bath and Hanover. Jacob came over for a brief visit in summer 1767, following Isaac’s death, but after giving virtuoso performances in the Pump Room he preferred to return to his high life in Hanover. Young Dietrich, now aged fifteen, came the following summer, and was given a fine holiday. Finally Alexander came and settled in 1770.68 William moved to a larger house at 7 New King Street, and Alexander was given the attic rooms, while William took over the first floor and had the reception rooms redecorated and furnished with a new harpsichord for his singing and music lessons.

All the time he was evidently worrying about Caroline, and finally in the spring of 1772, after long discussion with Alexander, he wrote to Hanover to ask if Caroline (then aged twenty-one, and having reached her majority) would like to join them at Bath. Knowing the opposition his proposal would face from their mother and Jacob, William put his suggestion in the most plain and practical terms, as Caroline recalled. She should make a trial as to whether ‘by his instructions I might not become a useful singer for his winter concerts and oratorios’. She could also become her brothers’ housekeeper. If after two years this ‘did not answer our expectations’, William would send her back. Significantly, he mentioned not a word of astronomy.69

Caroline longed to accept. But her mother fiercely objected, and so of course did Jacob. ‘I had set my heart upon this change in my situation, [but] Jacob began to turn the whole scheme to ridicule…[although] he never heard the sound of my voice except in speaking.’70 Caroline found her own way of stubbornly preparing for her escape. She practised singing the solo parts of oratorios ‘with a gag between my teeth’, so she could not be heard at home; and she secretly knitted enough cotton stockings for Dietrich to last him ‘two years at least’.

Finally Herschel himself went over to Hanover, and won his mother over by pointedly promising to settle an annuity on her to pay for a maid to replace Caroline. He never succeeded in getting his elder brother’s agreement, however. Jacob was away attending the Queen of Denmark at a court festival, and blustering letters arrived ‘expressing nothing but regret and impatience’ at the whole plan. William simply ignored them, and Caroline left ‘without receiving the consent of my eldest brother’. They departed on 16 August 1772, and from this moment William became the real head of the family.

Caroline still spoke practically no English. Her elfin face, badly marked by the childhood smallpox scars, made her painfully shy. At less than five feet she was of such diminutive stature that at times she seemed like a pixie out of some German folk tale. She had an almost childlike enthusiasm, energy and sense of mischief. The one known portrait of her at this age, a charming miniature silhouette, confirms this impression. Her profile is fine, pert, almost boyish, but with full, slightly pouting lips, and a neat, very determined little chin. Her hair bubbles round her head in a mass of curls, and falls down her back, where it is secured with a ribbon. She has a sprite-like quality about her.

Caroline adored the journey to England, keeping a wide-eyed diary of the trip, like an excited teenager. In Holland her hat was gloriously blown off into a canal. At night William made her sit outside on the top of the carriage so he could show her the constellations. On the crossing to Norfolk, one of their ship’s masts was carried away in a storm. Anchoring off the beach at Great Yarmouth (future home of Dickens’s Lil’ Emily), they were transferred with their bags to an open boat, rowed through the swell, and unceremoniously ‘thrown like balls’ onto the shore by two strapping English sailors.

Outside Norwich, the horses ran away with their carriage and they went ‘flying into a dry ditch’. In London they walked round the streets, seeing St Paul’s and the Bank, admiring the lights and examining the shops. But William would only pause outside those selling optical instruments-‘I do not think we stopped at any other.’ By the time they arrived by the overnight coach in Bath, Caroline reckoned she had only slept in a bed twice in eleven days. That was what it was going to be like living with her brother. ‘I was almost annihilated,’ she wrote triumphantly. William covered the whole journey in one sentence in his journal. ‘Set off on my return to England in company with my sister.’71


William now hustled Caroline into her new life. Summoning her to a seven o’clock breakfast, he began immediately to give her lessons in English and arithmetic, and showed her ‘booking and keeping household accounts of cash received and laid out’. He said he would give her three singing lessons a day, while she practised the harpsichord, dealt with the household linen and prepared the menus. She was given rooms in the attic with Alexander, but was commanded to act as hostess in the salon.

William treated her affectionately but sternly, insisting that she go out to shop on her own in the market at Bath, even though she still only spoke a few words of English, which she had, as she put it, ‘on our journey learned like a Parrot’.72 She found herself ‘alone among fishwomen, butchers, basket-men etc’, and also had to contend with the ‘hot-headed old Welsh woman’ who cooked. She felt she was encountering a ‘natural antipathy’ which the lower class of the English had against foreigners.73 But she could also be fierce herself: William’s neighbour, the motherly Mrs Bullman, she quickly dismissed as ‘very little better than an Idiot’, a term much favoured by Caroline.74

At first she struggled against Heimweh (homesickness) but she showed herself unexpectedly dauntless, and gradually settled into the taxing new routine. Breakfast was shortly after 6 a.m. (’much too early for me, who would rather have remained up all night’), followed by household accounts, shopping, laundry, three-hourly singing lessons, instruction in English and arithmetic, music copying, formal practice on the harpsichord kept in the front room, and reading out loud from English novels.75 ‘By way of relaxation’, she and William talked of nothing but astronomy. She never forgot ‘the bright constellations with which I had made acquaintance during the fine night we spent on the Postwagen travelling through Holland’. But she also remembered that William had promised to train her up as a professional concert singer, who would one day be independent.

It took time for the full emotional rapport to renew itself between the tall, handsome thirty-four-year-old bachelor brother, driven and ambitious, and the shy, tiny, awkward twenty-two-year-old sister, who had never before travelled outside her native Hanover, but who was bursting with unfulfilled dreams and longings. To begin with their relationship seemed formal, almost like that between father and daughter. In many ways William was quite withdrawn-enthusiastic and talkative in the mornings, but remote in the evenings after any guests had departed. ‘I seldom saw my Brother in the evening…He used to retire to bed with a basin of milk or glass of water, and Smith’s Harmonics and Optics, Ferguson’s Astronomy etc, and so went to sleep buried under his favourite authors; and his first thoughts on rising were how to obtain instruments for viewing those objects himself of which he had been reading.’ At breakfast, Caroline was usually subjected to ‘ample stuff for an astronomical Lecture’.76

William loved Caroline tenderly, but he also bullied her, in what he saw as a kindly pedagogical way. He could be an unsparing disciplinarian. She in turn adored him, but also feared him and grew impatient with him. He was always fierce in his domestic demands, and constantly required her to better herself: her English, her mathematics, her music and her astronomy. But gradually she learned to tease him and criticise him, while he came more and more to depend on her. In his daily notes and instructions he began to address her by the affectionate diminutive ‘Lina’, with its moonlike echo. Sometimes he even wrote it teasingly in French-‘Lina adieu’-or transliterated into Greek letters, ‘as you understand Greek’.77 Caroline always referred to him simply as ‘my dearest Brother’, or else ‘my beloved Brother’. For Caroline, William was initially the great liberator who had taken her out of the German house of bondage. But later their roles would subtly change. As William would observe to Nevil Maskelyne, it was not always self-evident which was the planet and which was the moon.

With the household running more smoothly, Herschel could now begin regular astronomical observations in their garden at night. Once Caroline had arrived, he found more time to explore the construction of telescopes. First he hired a two-and-a-half-foot-long Gregorian reflector telescope, which was too small; then in autumn 1772 he tried to construct an eighteen-foot refractor on the Huygens model. But its tube, which Caroline was instructed to make out of papier-mâché, was so long that it kept bending, like an elephant’s trunk. They substituted one made out of tin, but it was still not satisfactory. Then he wrote to London for materials to construct a five-foot reflector, but was told that no one made glass mirrors large enough (at least five inches in diameter) to fit it. It was then that Herschel took the crucial decision to try to cast, grind and polish his own metal mirrors or specula. To start with, he acquired some metal grinding and polishing tools from John Michel, a Quaker astronomer who had retired to Bath nursing some strange, unacceptable ideas-such as the existence of ‘black holes’ in space from which light itself could not escape.

The accelerating pace of Herschel’s experiments is caught in a memorandum of his purchases made over five months in 1773.

May 10th. Bought a book of Astronomy, and one of Astronomical tables.

May 24th. Bought an object glass of 10 foot focal length.

June 1st. Bought many eyeglasses, and tin tubes; made a pair of steps.

June 7th. Glasses paid for, and the use of a small reflector paid for.

June 14th. The hire of a 2 foot reflecting telescope for 3 months paid for.

Sept. 15th. Hired a 2 foot reflector.

Sept. 22nd. Bought tools for making a reflector. Had a metal [mirror] cast.

Oct. 2nd. Bought a 20 foot object glass, and 9 eyeglasses. Emerson’s Optics. Attended private [music] scholars as usual.78

In June 1773 Herschel decided to attempt to make his own large reflector telescope, using metal mirrors as big as six inches in diameter.79 It was a complicated and above all laborious task, requiring the casting, grinding and polishing of ‘speculum metal’, made of an alloy of white tin and brass. Three-inch mirrors were quite common, but a six-inch-diameter mirror with a precise concave surface required a technical feat that had never been achieved before. It called for a series of ingenious ‘contrivances’, which took Herschel back to his boyhood days, and all his old enthusiasm and ingenuity bubbled back.

The casting first required the construction of a small iron furnace and special moulds. These, Herschel found after many experiments, could best be made from a dried non-porous natural loam, formed from pounded horse-dung. Once cast, the speculum metal had to be hand-ground with a solution of ‘coarse emory and water’ to achieve the required concave curve, and finally polished, ‘with putty or oxide of tin or pitch’, for hours on end to achieve an absolutely smooth reflective surface. It was an exhausting, and occasionally dangerous, physical process, needing endless trial and error. The furnace was liable to explode, and Herschel found that the polishing had to be done without pausing-sometimes for many hours on end.80 If the polishing paused for even a few seconds in the final stages, the metal would harden and mist over, and the mirror would be useless.

All the work had to be carried out at 7 New King Street, turning the elegantly furnished house (intended of course for music-making and teaching) into a pungent, chaotic workshop. Initially Caroline was appalled at this transformation: ‘To my sorrow I saw almost every room turned into a workshop. A Cabinet-maker making a Tube and stands of all descriptions in a handsome furnished drawing room! Alex putting up a huge turning machine…in a bedroom for turning patterns, grinding glasses & turning eye-pieces etc. At the same time Music durst not lay entirely dormant during the summer, and my Brother had frequent rehearsals at home.’81

Caroline was gradually becoming William’s closest assistant. She was up at all hours, turning her hand to every practical need, housekeeping, shopping in the market, dealing with visiting music scholars, taking Pump Room choirs for singing practice, ‘lending a hand’ in the workshop, even reading aloud from inspiring fiction (in her bad accent) while William sweated over the mirror-polishing.82 Their choice of books seems intended to relieve the monotony of the work: Don Quixote, the Arabian Nights, Sterne’s Tristram Shandy-all tales of fantastic adventures or eccentric heroes. Caroline does not seem to have been permitted the most fantastic and eccentric of them all, William’s favourite, Paradise Lost.

Sometimes she even provisioned William while he worked, literally putting drinks and bits of food into his mouth. On at least one momentous occasion, this extraordinary provisioning process lasted for sixteen hours without a break. It was as if Caroline was a mother bird feeding a demented nestling. Something of William’s obsessional dedication, and Caroline’s ambivalent feelings about it, come out in the way she described this in her journal: ‘My time was so much taken up with copying Music and practising, besides attendance on my Brother when polishing, that by way of keeping him alife I was even obliged to feed him by putting the Vitals by bits into his mouth-this was once the case when at the finishing of a 7 foot mirror he had not left his hands from it for 16 hours together…And generally I was obliged to read to him when at some work which required no thinking, and sometimes lending a hand, I became in time as useful a member of the workshop as a boy might be to his master in the first year of his apprenticeship.’83

Much later, Victorian illustrators would make this into a comfortable domestic scene, a harmonious couple in an elegant drawing room, with convenient refreshments on a nearby table. In fact these epic polishing sessions took place downstairs, at the workbench of the unheated, stone-flagged basement in New King Street. Here William and Caroline were surrounded by tools and chemicals, and the distinct, pungent smell of the horse-dung moulds. It was dirty, monotonous and exhausting work, for which they wore rough clothes, and ignored ordinary household routines and niceties.84

Caroline’s account is light-hearted and self-denigrating, in her usual manner, and yet faintly resentful. Her sense of herself as William’s ‘boy’ apprentice suggests a measure of physical subordination and discipline. It also hints at an undignified negation of her sex. Here William was her ‘master’, not her kindly brother or patient teacher. Moreover, she saw herself as his ‘first year’ boy, at a time when apprenticeships normally lasted seven years. Though willingly undertaken, the work must have been frustrating and even perhaps humiliating for her. (What, for example, did she do if William needed to urinate during his epic polishing sessions?) Once again her account of the brother-sister relationship is problematic.

Meanwhile Herschel revealed extraordinary mechanical ability, combining the manual dexterity of a musician with almost ruthless determination and stamina. On one occasion he insisted on sharpening his instruments on the landlord’s grindstone in the yard after midnight, and came back fainting, with one of his fingernails ripped off. On another, the casting exploded in the basement workshop, and a stream of white-hot metal shot across the stone floor, cracking it from end to end and nearly laming them both.

By 1774 Herschel had successfully assembled his first five-foot reflector telescope, with a home-made metal speculum mirror of six-inch diameter (about the size of a side-plate). His Observation Journal records proudly: ‘December. At night I made astronomical Observations with telescope of my own construction.’85 As if to distinguish it from the standard tubular refractors, he had a beautiful octagonal case of gleaming mahogany panels made for it by their cabinet-maker. With its bright brass eyepiece and small sighting scope, it looked like a fine piece of Georgian furniture, not unworthy of Chippendale himself.

It was immediately apparent that Herschel had created an instrument of unparalleled light-gathering power and clarity. He saw, for example, what very few astronomers even suspected: that the Pole Star-which had been the key to navigation, and the poet’s traditional emblem of steadiness and singularity, for centuries-was not in fact one star at all, but two stars. This observation was not officially confirmed until Herschel received a letter from Joseph Banks, as President of the Royal Society, nearly ten years later, in March 1782.86

The first objects Herschel studied from his garden were his old travelling companion, the moon, and then two of the most prominent of the mysterious nebulae, or ‘star-clouds’, about which almost nothing was yet known. The first nebula was the one in the skirts of Andromeda, just visible with the naked eye as a faint primrose gaseous whorl beyond Cassiopeia; the other was in Orion, the mysterious blue star cluster, two stars down on the Hunter’s sword blade. These colour-tints were immensely enhanced by Herschel’s reflector, and he was soon producing wonderfully evocative colour descriptions of stars and planets. The nine-teenth-century observer T.H. Webb would complain that Herschel was rather too ‘partial to red tints’, though whether this was a purely subjective problem, a physiological one, or down to his speculum metal being a better reflector at the long-wavelength end of the spectrum, is still open to debate. The modern Hubble images are even more cavalier about colouring deep-space objects.87

From the start, Herschel’s observations have a note of authority, and he is ready to challenge current astronomical thinking. His Observation Journal for 4 March 1774 reads: ‘Saw the lucid spot on Orion’s Sword, thro’ a 5 ½ foot reflector; its shape was not as Dr Smith has delineated in his Optics; tho’ something resembling it…From this we may infer that there are undoubtedly changes among the fixt stars, and perhaps from a careful observation of this spot something might be concluded concerning the Nature of it.’88 Even at this early stage Herschel has the notion of a changing universe, and that nebulae might hold some clue to this mystery. Each winter between 1774 and 1780 he made detailed drawings of Andromeda and the Orion nebula to see if any alterations could be identified.89 

The nebulae represented a new field of sidereal or stellar astronomy. Only thirty nebulae were known in the 1740s, at the time of Herschel’s birth. By the time Herschel began to study them in the mid-1770s, Charles Messier in Paris had catalogued just under a hundred. Within a decade, by the mid-1780s, Herschel would have increased this tenfold, to over a thousand nebulae.90 No one really knew their composition, origins or distance. In general they were thought to be a few loose clouds of gas, hanging static in the Milky Way, some loose flotsam of God’s creation, and of little cosmological significance. Herschel suspected that they were star clusters at immense distances, whose composition might hold a clue to an entirely new kind of universe.

Sometimes, to observe the northern sky, he took his telescope out into the street at the front of the house, and dictated notes to Caroline. That autumn they attended together a return series of Ferguson’s astronomy lectures, given at the Pump Room by popular demand. Herschel’s journal records that he was still giving eight one-hour music lessons a day, and Caroline was continuing several hours’ singing practice.91 But the music scholars were sometimes surprised by Herschel ‘dropping his violin’ in the middle of the last evening lesson, and jumping up to peer at some particular group of stars from the window. One startled student recalled: ‘His lodgings [at Rivers Street] resembled an astronomer’s much more than a musician’s, being heaped up with globes, maps, telescopes, reflectors etc, under which his piano was hid, and the violoncello, like a discarded favourite, skulked away in a corner.’ Herschel himself said that some of his pupils ‘made me give astronomical instead of music lessons’.92

Back in Hanover, Anna and Jacob were still expressing doubts about Caroline living in England. Again, Herschel did not mention astronomy, but revealed that he had established a small millinery business on the ground floor at 5 Rivers Street, to supplement the household income, which Caroline was running successfully as well as pursuing her singing.93 He then slipped over to reassure them in the summer of 1777, and for the first time wrote a series of confidential letters to Caroline in English. ‘Mama is extremely well and as I have represented things gives her consent to you staying in England as long as you and I please. I wish very much to see my own home again [Bath], and conclude at present, remaining your affectionate Brother, Wm. Herschel…I hope to be in Bath about 14-16 of Sept.’94

Caroline was continuing her singing training, and beginning to perform regularly in Herschel’s concerts at the Pump Room. But she ‘could not help feeling some uneasiness’, as she put it, about her future prospects, as more and more of William’s time was ‘filled up with Optical and Mechanical works’.95 Once they went together to fulfil a singing engagement in Oxford, but Caroline remembered it largely for the perilous journey home, ‘for the jaunt was made in a single horse Chaise, and my Brother was not famous for being a good driver’.96

Then William gave her ten guineas-a very considerable sum-to spend on whatever evening dress she liked, for her musical performances. She was overjoyed when the proprietor of the Bath Theatre, Mr Palmer, solemnly pronounced her to be ‘an Ornament to the Stage’, a compliment she never forgot.97 On 15 April 1778 she was advertised, for the first time, as the principal solo singer in a programme of selections from Handel’s Messiah at the Bath New Rooms. As this was Herschel’s own end-of-season ‘Benefit Concert’, it was clearly he who promoted her. Her performance was such a success that she was offered her first solo professional engagement by a company at the Birmingham Festival for the following spring. Here at last was her chance of an independent career, at the age of twenty-eight. But after consultation with William, she turned it down, announcing that she was ‘resolved only to sing in public where her brother was conducting’. Consciously or not, she had made a decision about her future with William.98

It may be no coincidence that the following year, 1779, Herschel began a much more serious and regular pattern of observations. He recorded: ‘January. I gave up so much of my time to astronomical preparations that I reduced the number of my [music] scholars so as not to attend more than 3 or 4 a day.’99 He had decided on his first major astronomical project: to establish a new catalogue of so-called ‘double stars’.

John Flamsteed had observed over a hundred double stars, but had established no special record of them, and there were obviously many more to be found. The value of double stars was that they might provide a method of gauging the earth’s distance from the rest of the Milky Way, by the measuring of parallax.

Although distances within the immediate solar system-to the moon and notably to the sun (using the Transit of Venus observations)-had been approximately measured, there was no general idea how far away the stars were, or what the size of the Milky Way might be. Kant, for example, assumed that Sirius (the Dog Star), because of its brightness, was probably the centre of the entire Milky Way galaxy, and possibly of the whole universe.100 In fact it is one of our nearest stars, just over 8.7 light years away.

Most current ideas about the cosmos were small-scale. It was widely believed that the earth was a few thousand years old at most (Biblical calculations gave 6,000 years), and that the universe might stretch out a few million miles ‘above’ the earth. The ‘fixed stars’ revolved in an unchanging pattern, and their brightness or magnitude was probably a function of their size, rather than their distance. So a faint star was probably comparatively small, rather than comparatively far away-a perfectly reasonable assumption. (One of Herschel’s most simple and radical ideas was to assume exactly the opposite.) The physical closeness of the stars and planets also explained their astrological ‘influences’. The universe was small, closely connected, largely unchanging (except for comets), and almost intimate.

Nevertheless, the eighteenth century had been rich in speculative theories about the possibility of a ‘Big Universe’. These included Thomas Wright’s Original Theory or New Hypothesis of the Universe (1750) and Kant’s Universal Natural History of the Heavens (1755), which first proposed-though without observational evidence-that there might be ‘island universes’ outside the Milky Way, that some distant stellar systems might be altering, and that the whole cosmos might be in some sense ‘infinite’, though it was not clear what exactly ‘infinite’ might mean, as hitherto it was a quality possessed only by God and mathematics. Herschel himself had added to these theoretical accounts with an early paper, eventually published by the Bath Philosophical Society, ‘On the Utility of Speculative Enquiries’.

All these speculative essays assumed the high probability that extraterrestrial life existed, either within the immediate solar system, or further out among the stars. James Ferguson, for example, stated in the opening of his Astronomy Explained (1756) that the entire universe was evidently populated, if not positively crowded, with living forms: ‘Thousands upon thousands of Suns…attended by ten thousand times ten thousand Worlds…peopled with myriads of intelligent beings, formed for endless progression in perfection and felicity.’101 It was further assumed that such life forms, though not necessarily human in appearance, would have developed civilisations and sciences superior to our own. The question of whether they were ‘fallen’ in a religious sense, and required Redemption according to Christian doctrine, remained a moot point among astronomers, few of whom would have considered themselves as ‘atheists’ in any modern sense. ‘An undevout astronomer is mad,’ as the poet Edward Young reflected in Night Thoughts (1742-45).

However, the growing sense of the sheer scale of the universe, and the possibility that it had evolved over unimaginable time, and was in a process of continuous creation, did slowly give pause for thought. For a poet like Erasmus Darwin, in The Botanic Garden(1791), it put the Creator at an increasing shadowy distance from his Creation.102

This interest in extraterrestrial life was one of the reasons that Herschel remained so fascinated by the surface of the moon, with its mysterious mountains and craters, and dramatically shifting patterns and colours of shadow. When it was invitingly at the crescent (the best time to study surface detail), but too low to be observed from his tiny back yard, he would take his seven-foot telescope out into the cobbled street in front of the house. So it was, in December 1779, while Herschel was ‘engaged in a series of observations on the lunar mountains’, that a passing carriage stopped, a young gentleman sprang out, and he had his first historic meeting with Dr William Watson, junior. This was Herschel’s first really important scientific contact in England, one not made until he was forty-one. Watson was only thirty-three.


Herschel later recalled the moment with appropriate gravity: ‘The moon being in front of my house, late in the evening I brought my seven-foot reflector into the street…Whilst I was looking into the telescope, a gentleman coming by the place where I was stationed, stopped to look at the instrument. When I took my eye off the telescope, he very politely asked if he might be permitted to look in…and expressed great satisfaction at the view. Next morning, the gentleman, who proved to be Dr Watson, junior (now Sir William), called at my house to thank me for my civility in showing him the moon.’103

Caroline remembered it rather less formally. Herschel and Watson were so immediately taken with each other that very night that they burst into the house and began ‘a conversation which lasted until near morning; and from that time on [Dr] Watson never missed to be waiting on our house against the hours he knew my Brother to be disengaged’.104

Watson warmly befriended Herschel, and encouraged his work even to the extent of helping with pounding horse-dung moulds and casting speculum mirrors. He quickly became what Caroline called ‘almost an intimate of the family’.105 He had Herschel elected to the Bath Philosophical Society as ‘optical instrument maker and mathematician’ (no mention of musician), and over the next two years encouraged him to submit no fewer than thirty-one papers at its meetings. These included ‘On the Utility of Speculative Enquiries’, ‘On the Existence of Space’, and further unconventional observations on the moon. They are evidence of the extraordinary intellectual ferment that had seized upon Herschel.

His notion of the cosmos was already far from conventional, and several of these papers were what would now be called ‘thought experiments’. In his ‘Space’ paper, delivered on 12 May 1780, he astonished his audience with his radical thoughts on time and distance: ‘Huygens said that it was possible some of the fixt Stars might be so far off from us that their light tho’ it travelled ever since the Creation at the inconceivable rate of 12 million of miles per minute, was not yet arrived to us. The thought is noble and worthy of a Philosopher. But [should] we call this immense distance a mere imagination? Can it be an abstract Idea? Is there no such thing as space?’106

In the case of his moon speculations, he raises the question whether a scientific idea has to be ‘correct’ to be significant. One of Herschel’s most ingenious ideas was that moon craters were artificially constructed circular cities (or ‘Circuses’), built especially to harness solar power for the lunar inhabitants: ‘There is a reason to be assigned for circular Buildings on the Moon, which is that as the Atmosphere there is much rarer than ours and of consequence not so capable of refracting and (by means of clouds shining therein) reflecting the light of the Sun, it is natural enough to suppose that a Circus will remedy this deficiency. For in that shape of Building one half will have the direct, and the other half the reflected, light of the Sun. Perhaps, then on the Moon every town is one very large Circus?’107 

So, besides the two main projects, to record all new double stars and all new nebulae, Herschel was also embarked on a third and partly secret programme in 1779: to discover life on the moon. For some time he did not risk sending this section of the lunar paper to Maskelyne at the Royal Society, but both Watson and Caroline were aware of it. This was one of the reasons he needed to construct better telescopes.

The moon project had begun with a long entry made in his Observation Journal for 28 May 1776. He saw ‘what I immediately took to be woods or large quantities of growing substances in the Moon’. With a certain angle of solar light, some of the lunar shadows looked like ‘black soil’ spread down a mountainside. Other puzzling stippled shadows, especially in the Mare Humorum, Herschel believed were enormous ‘forests’, made up of huge, spreading leafy canopies, or at least ‘large growing substances’. Because of low lunar gravity, this gigantic ‘vegetable Creation’ was evidently ‘of a much larger size on the Moon than it is here’.108

Similarly, he tended to believe that there were so many of the smaller moon craters that they must be artificial constructions: ‘By reflecting a little on this subject I am almost convinced that those numberless small Circuses we see on the Moon are the works of Lunarians and may be called their Towns.’ Nonetheless, true science required not speculation but accurate observation and telescopic proof. ‘But this is no easy undertaking to make out, and will require the observation of many a careful Astronomer and the most capital Instruments that can be had. However this is what I will begin.’109

The light-gathering power of Herschel’s seven-foot reflector allowed him to see many objects that no previous astronomers had accurately observed, or at least recorded. With Caroline taking notes at his dictation, they began to compose a new catalogue of double stars, and to develop a system of recording the exact time and position of any unusual stellar phenomena not previously catalogued by Flamsteed. By this means Herschel began to build up an extraordinary, instinctive familiarity with the patterning of the night sky, which gradually enabled him to ‘sight-read’ it as a musician reads a score. He would later himself use such musical analogies to explain the technique and art of observation.

In early 1781 it was decided to close down the millinery business at 5 Rivers Street. William and Caroline moved back to the substantial three-storey terraced house at 19 New King Street, where the telescope equipment was immediately set up in the fine little back garden: ‘beyond its walls all [was] open as far as the river Avon’. Here, as Caroline noted modestly, ‘many interesting discoveries were made’. At first she however had to remain at Rivers Street to oversee the selling off of the linen stock, and she missed the first few nights of observation in March. She subsequently recorded, with unusual care, that she did not return to New King Street until 21 March-as it turned out a historic absence.110

During these nights around the spring equinox Herschel was observing alone, and as well as continuing with their catalogue of double stars, he gave himself up to making drawings of Mars and Saturn. Possibly he was ranging more freely than usual, or possibly he was testing his ability to ‘sight read’ the sky. At all events, on Tuesday, 13 March 1781, slightly before midnight, Herschel spotted a new and unidentified disc-like object moving through the constellation of Gemini. This discovery would change his entire career, and become one of the legends of Romantic science.

It also raises an intriguing question: how soon did Herschel know-or suspect-what he had discovered? It seems from his Observation Journal at the time, that what he thought he had found was a new comet. The following laconic account appears in his ‘First Observation Book’ for 12 and 13 March 1781

March 12

5.45 in the morning.

Mars seems to be all over bright but the air is so frosty & undulating that it is possible there may be spots without my being able to distinguish them.

5.53 I am pretty sure there is no spot on Mars.

The shadow of Saturn lays at the left upon the ring.

Tuesday March 13

Pollux is followed by 3 small stars at about 2’ and 3’ [minutes of arc] distance.

Mars as usual.

In the quartile near Zeta Tauri the lowest of two is a curious either nebulous star or perhaps a Comet.

A small star follows the Comet at 2/3rds of the field’s distance.111

There are no further remarks for these nights, and certainly no expression of excitement or anticipation. On the following night, Wednesday, 14 March, it was either cloudy, or Herschel did not bother to observe, for there is no entry. He may have been prevented by an official engagement to play the harpsichord at the Bath Theatre, or to rehearse oratorios with Caroline.112 On 15 March there are short observations on Mars and Saturn, accompanied by some drawings of them made between 5 and 6 a.m., but nothing further about the ‘curious nebulous star or comet’. On Friday, 16 March there is again no entry. But Herschel may have been reflecting on his sightings, and talking to Caroline over the weekend, for finally, on the night of Saturday, 17 March there is the first clear sign that he was definitely in pursuit of the mysterious new object.

Saturday March 17

11pm. I looked for the Comet or Nebulous Star and found that it is a Comet, for it has changed its place. I took a superficial measure 1 rev, 6 parts and found also that the small star ran along the other [cross] wire…Position exactly measured 91′96…

Once Caroline had returned to New King Street on the twenty-first, there are regular entries in late March following the ‘comet’, and attempts to measure its diameter with William’s newly designed micrometer. For example, on 28 March the Observation Book reads: ‘7.25 pm. The diameter of the Comet is certainly increased, therefore it is approaching.’113 The increase in apparent size was a further indication of ‘proper motion’ and a solar orbit; and further proof that it could not possibly be a fixed star. But if it was a comet, there should be a slightly blurred, fiery outline and a distinct tail or ‘coma’. Here Herschel’s beautifully clear reflector images, even more than his high-magnification eyepieces, came into their own. In early April, some three weeks after his first sighting, Herschel made what seemed to be a definitive observation.

Friday April 6

I viewed the Comet with 460 [magnifications] pretty well defined, no appearance of any beard or tail. With 278 [magnifications] perfectly sharp and well defined.114

Though Herschel was scrupulously careful not to say so in his Observation Book, the sharp, round definition and the lack of any tail could only mean one thing: a new ‘wanderer’, or planet. What in fact he had observed was the seventh planet in the solar system, beyond Jupiter and Saturn, and the first new planet to be discovered for over a thousand years (since Ptolemy). He would name it patriotically after the Hanoverian king, ‘Georgium Sidus’ (‘George’s Star’), but it eventually became known to European astronomers as Uranus. ‘Urania’ was the goddess of astronomy, and the new planet was seen to mark a rebirth in her science.

Yet there was no Eureka moment: quite the opposite. For the next few weeks there was a great deal of uncertainty about what sort of astronomical body Herschel had found. Nowhere does the word ‘planet’ appear in his Observation Journal for that spring of 1781, and there was no popular reporting of the news in the magazines. The following year, when the sensation was widely known, it would be very different, as Caroline remarked: ‘Since the discovery of the Georgium Sidus, I believe few men of learning or consequence left Bath before they had seen and conversed with its discoverer.’ But for the time being there were just endless measurements with the micrometer, ‘and a fire to be kept in, and a dish of Coffee during the long nights of watching’. She added wryly: ‘I undertook with pleasure what others might have thought a hardship.’115

On 22 March Herschel tentatively communicated his preliminary observations of ‘a Comet’ to William Watson, who passed them on to Nevil Maskelyne and Joseph Banks at the Royal Society.116 Maskelyne immediately contacted other European astronomers, notably Charles Messier in Paris, asking for their opinion.117 A week later Herschel followed this up with a direct report to the Royal Society, which was logged in the Society’s ‘Copy Journal Book’ for 2 April. Now he expressed barely muted excitement: ‘Saw the Diameter of the Comet extremely well defined and distinct; with several different powers thro’ my 20 foot Newtonian reflector. It was a glorious sight, as the Comet was placed among a great number of small fixt stars that seemed to attend it.’118

Remembering Herschel’s ‘lunacies’ of the previous year, Maskelyne was initially sceptical. He found great difficulty in even locating the new object with his own telescopes at Greenwich, a difficulty increased by Herschel’s inability to provide the conventional mathematical coordinates. At this stage Herschel located all his stars on hand-drawn star maps-what he called ‘an eye-draught’-an amateur technique that again visually recalls his familiarity with musical scores.119 It was not until 4 April that Maskelyne wrote cautiously to Watson (still not to Herschel directly) that he had finally found the new ‘star’, and observed that it had just discernible ‘motion’. However, he prudently, and not unreasonably, hedged his bets: ‘This [the motion] convinces me it is a comet or a planet, but very different from any comet I ever read any description of or saw. This seems a Comet of a new species, very like a fixt star; but perhaps there may be more of them.’ This safely covered all the options. He added a pointed postscript: ‘PS I think [Herschel] should give an account of his telescope, and micrometers.’120

The Astronomer Royal was in a dilemma. He had no reason to accept Herschel as a reliable astronomer, and to declare a new planet prematurely might bring himself and the Royal Society into disrepute, and even ridicule. On the other hand, to reject what might be the greatest British astronomical find of the century, especially if the predatory French astronomers accepted it first (and even named it), would be even more damaging. He was also aware that Banks regarded this as a crucial moment in his presidency, and in the fostering of good relations between the Royal Society and the Crown. King George III was particularly fascinated by stars, and particularly keen to outdo the French.

Maskelyne finally chose to act as a man of science: he went back to his own telescopes, and from 6 to 22 April made his own observations. He was, after all, acting precisely according to the motto of the Royal Society itself: Nullius in Verba-‘Nothing upon Another’s Word’. On 23 April he at last wrote directly to ‘Mr William Herschel, Musician, near the Circus, Bath’. He began prudently, but ended firmly.

Greenwich Royal Observatory, April 23, 1781

Sir, I am to acknowledge my obligation to you for the communication of your discovery of the present Comet, or planet.

I don’t know which to call it. It is as likely to be a regular planet moving in an orbit nearly circular round the sun, as a Comet moving in a very eccentric ellipsis. I have not yet seen any coma or tail to it…

This tipped the argument towards a planet, but was not a decisive opinion. Maskelyne then went into technical details about their respective telescopes-especially the need for ‘very firm stands’-and the difficulties of using micrometers to measure apparent changing diameters (and hence establish a possible planetary orbit): ‘If the light of the small planet is not still, & free from scintillations, it is impossible to prove it to have any other than a spurious diameter that may arise from the faults to which the best telescopes are subject.’ Nonetheless, he praised Herschel for making ‘very good observations’.

Finally, in his last paragraph, he committed himself. ‘On the 6th April I viewed the Comet with my 6 foot reflecting telescope and the greatest power 270, and saw it a very sensible size but not well defined. This however showed it to be a planet and not a fixt star, or of the same kind of fixt stars as to possessing native light with an insensible diameter. I am Sir, etc etc, N. Maskelyne.’121

Herschel had gained an invaluable ally. He immediately sent up a brief, masterly paper which was read at the Royal Society on 26 April. It was entitled simply ‘An Account of a Comet’, and was published in the Philosophical Transactions in June. He stated that ‘between ten and eleven in the evening’ of 13 March 1781 he had at once recognised a new object of ‘uncommon magnitude’ in Gemini, and immediately ‘suspected it to be a comet’. But from the account he then gave of its magnitude, clarity of outline and ‘proper motion’ it was clear that Herschel was now claiming that the ‘comet’ was really a new planet. Though, no doubt advised by Watson, he did not actually say so. To support this, he also claimed that the object remained perfectly round, without the least appearance of comet’s tail, when magnified 270, 460 and 932 times-the latter magnifications being far beyond what even Maskelyne’s Greenwich telescopes could achieve. All this naturally excited even more controversy than his moon paper, and some murmurs of dissent.122

Maskelyne nevertheless stoutly confirmed his opinion to Banks that their dark horse, the ‘musician of Bath’, had made a revolutionary discovery, and had ‘much merit’. Yet he could not suppress a touch of rueful irony. ‘Mr Herschel is undoubtedly the most lucky of Astronomers in looking accidentally at the fixt stars with a 7 foot reflecting telescope magnifying 227 times to discover a comet of only 3’ [seconds of arc] diameter, which if he had magnified only 100 times he could not have known from a fixt star…Perhaps accident may do more for us than design could; and this makes one wish that the number of astronomers was multiplied in order to increase our chance of new discoveries.’123 This suggestion that the discovery had been ‘accidental’, and that he had been ‘lucky’, was to grow increasingly disturbing to Herschel.124

Maskelyne had made public his support of Herschel just in time. On 29 April Messier wrote directly to ‘Monsieur Hertsthel at Bath’ from Paris, congratulating him-‘this discovery does you much honour’-and giving his opinion that this was very likely to be the seventh planet in the solar system. Messier had himself, he said modestly, discovered no fewer than eighteen comets in his lifetime, and this resembled none of them: it was ‘a little planet with a diameter of 4 to 5 seconds, a whitish light like that of Jupiter, and having the appearance when seen with glasses of a star of the 6th magnitude’. He signed ‘with consideration and respect’ as ‘Astronomer to the Navy of France, of the Academy of Sciences, France’.

As Maskelyne and Banks were only too aware, Messier’s congratulations would soon carry the weight of the entire French Académie des Sciences.125 Throughout the spring and summer months of 1781, more and more astronomers-in France, Britain, Germany, Italy and Sweden-observed the tiny moving speck, and took the view that it was indeed a planet circling in a massive ellipse beyond Saturn. These included Jacques Cassini, Henry Cavendish and Pierre Méchain. In October Anders Lexell, the celebrated Russian mathematician, wrote from his observatory far away in St Petersburg, sending a fully computed orbit and adding his congratulations. Using a series of parallax readings, he calculated that the planet was large and unbelievably remote, over sixteen times further from the sun than the earth, and twice as far out as Saturn. The size of the solar system had been doubled. Jérôme Lalande, who also computed the orbit, later said that this was the moment when the Académie des Sciences finally accepted the new planet-seven months after it had been sighted. Lalande himself suggested it should be christened ‘Herschel’.

It is suggestive that it was mathematical calculation, rather than astronomical observation, which finally convinced the scientific community that a seventh planet really did exist. One of the things Lexell’s calculation showed was that Herschel’s vivid impression that the planet was increasing in apparent diameter throughout March and April (and therefore approaching the earth) must have been the product of his growing concentration and excitement, since it was actually getting smaller and moving away. Lexell continued to work patiently for several years on his calculations, and later came up with the revised figure of 18.93 times the distance from the earth, impressively close to the modern computer-generated figure of 19.218. (In fact, as the planet’s orbit is elliptical not circular, the distance varies: at its closest it is 18.376 and at its furthest it is 20.083.)

In May, Watson proudly took Herschel up to London to meet his father Sir William, and to renew his now extremely cordial relations with Nevil Maskelyne. Together with the wealthy Deptford astronomer Alexander Aubert, they all dined with Sir Joseph Banks at the Mitre Club, the tavern much favoured by Dr Johnson. This was Herschel’s first meeting with the inner circle of British astronomers, and it was a great success. There was an air of suppressed triumph and excitement. Banks, in high spirits, seized his hand, congratulated him on ‘the great discovery’, and announced that he was to be elected to the Royal Society and awarded the Copley Gold Medal forthwith-within the next fortnight!126 He claimed it as a decisive British victory over French astronomy, and the eminence of Messier, Pierre Laplace and Lalande, who had hitherto dominated European astronomy.

In fact Banks’s enthusiasm had rather got the better of him. The Copley Medal and the fellowship election had to go through the Society’s plodding bureaucratic procedures, which took another six months. Maskelyne used the interval to write warmly to Herschel in August: ‘I hope you will do the astronomical world the favour to give a name to your new planet, which is entirely your own, and which we are so much obliged to you for the discovery of.’127

It was subsequently shown that ‘Georgium Sidus’ had actually been observed and recorded at least seventeen times between 1690 and 1781, and was even catalogued by Flamsteed. But it had always been dismissed as a minor ‘fixed’ star. It was only Herschel’s observational genius-and the quality of his seven-foot reflector-which identified it as a large, steadily moving body in regular orbit round the sun: a true planet. And it was Maskelyne who, by promptly supporting Herschel and bringing his observations to the attention of other leading European astronomers, confirmed the discovery and had it accepted by the scientific community at large. It later became clear that Uranus was a weird blue ice giant (not ‘little’ as Messier thought), twice the distance of Saturn, and taking 84.3 years to complete a solar orbit. It is the only planet in the solar system which is tilted ‘on its side’, so its axis of rotation, or spin, is horizontal to its solar orbit.

In November Banks wrote a friendly and characteristically droll letter to Herschel, asking him for details of how he made the discovery that famous night, and all the difficulties ‘etc etc’ it caused him. He wanted to refer to these when presenting him to the assembled members of the Royal Society in London the following month: ‘Sir, The Council of the Royal Society have ordered their Annual Prize Medal to be presented to you in reward for your discovery of the new star. I must request that (as it is usual for me on that occasion to say something in commendation of the discovery) you will furnish me with such anecdotes of the difficulties you experienced etc etc…as you may think proper to assist me in giving due praise to your industry and ability.’

Banks, in high good humour, also enjoyed putting Herschel on his mettle. ‘Some of our astronomers here incline to the opinion that it is a Planet, and not a Comet. If you are of that opinion, it should forthwith be provided with a name, or our nimble neighbours, the French, will certainly save us the trouble of Baptizing it.’128

Herschel, again advised by Watson, asked Banks if he could name the planet after the King, ‘Georgium Sidus’, a sound and self-effacing diplomatic stroke from a fellow Hanoverian.129 But he was less easy about the continuing murmurs in some quarters of the Royal Society that his discovery had been in some sense ‘accidental’. This struck at his very notion of scientific method. He wrote insistently, even angrily, to Banks just before the ceremony on 19 November: ‘The new star could not have been found out even with the best telescopes had I not undertaken to examine every star in the heavens including such as are telescopic, to the amount of at least 8 or 10 thousand. I found it at the end of my second review after a number of observations…The discovery cannot be said to be owing to chance only it being almost impossible that such a star should escape my notice…The first moment I directed my telescope to the new star, I saw with a power of 227 that it differed sufficiently from other celestial bodies; and when I put on the higher powers of 460 and 932 was quite convinced it was not a fixt star.’130

This claim was to become a point of honour with Herschel, often repeated. In September 1782 he wrote to Lalande in Paris, stating emphatically that the discovery ‘was not owing to chance’. Since he was embarked on a regular review of the sky, ‘it must sooner or later fall into my way, and as it was that day the turn of the stars in that neighbourhood to be examined, I could not very well overlook it’.131 The following year he wrote to the German astronomer Georg Christoph Lichtenberg at Göttingen, repeating that it was ‘not by accident’, and adding: ‘when I came to Astronomy as a branch of [mathematics] I resolved to take nothing upon trust but see with my own eyes all what other men had seen before’.132 Lichtenberg replied enthusiastically (in German): ‘Mein Gott! If I had only known, when I was for a few days in Bath in October 1775, that such a man lived there! As I am no friend of tea rooms, nor of cards or balls, I was much ennuyéd and spent my time at the top of the [cathedral] tower with a field glass…’

When he came to write an autobiographic sketch for his friend Dr Hutton in 1809, Herschel was more insistent than ever: ‘It has generally been supposed that it was a lucky accident which brought this star to my view; this is an evident mistake. In the regular manner I examined every star of the heavens, not only of that magnitude but many far inferior, it was that night its turn to be discovered. I had gradually perused the great Volume of the Author of Nature and was now come to the seventh Planet. Had business prevented me that evening, I must have found it the next, and the goodness of my telescope was such that I perceived its planetary disk as soon as I looked at it; and by application of my micrometer, I determined its motion in a few hours.’133

This claim is not entirely borne out by his original Observation Journal. His first sweep or ‘review’ of double stars, begun in 1779, had not revealed the Georgium Sidus, so discovery on the second was not inevitable. Nor was recognition instant when it came. The journal reveals no precise Eureka ‘first moment’ on 13 March, only the hardening suspicion drawn out over five days to Saturday, 17 March that the strange body had ‘proper motion’, but was neither a ‘nebulous star’ nor a ‘comet’, and so was very probably a new planet. But it was Nevil Maskelyne who was the first to say so explicitly in writing, in April.

Nevertheless, Herschel’s discovery was an astonishing feat. It became his professional signature, and a historic moment for cosmology. It is hardly surprising that over the years he continued romantically to refine the story, and compressed his discovery into a single wondrous night, the inspired work of a glorious ‘few hours’. Caroline never commented on this, although it seems clear that she was present during the critical nights of measuring between 21 March and 6 April 1781. The effect of this account was to present an engagingly romantic image of science at work: the solitary man of genius pursuing the mysterious moment of revelation.

Joseph Banks’s presentation speech, when awarding the prestigious Copley Gold Medal for the best work in any scientific field during the year 1781, in front of the assembled Fellows of the Royal Society, was unreservedly complimentary to Herschel. The discovery of the new planet was the first great success of Banks’s new presidency. In his most expansive and jovial mood, he accordingly projected a visionary future for Herschel’s astronomy: ‘Your attention to the improvement of telescopes has already amply repaid the labour which you bestowed upon them; but the treasures of heaven are well known to be inexhaustible. Who can say but your new star, which exceeds Saturn in its distance from the sun, may exceed him as much in magnificence of attendance? Who can say what new rings, new satellites, or what other nameless and numberless phenomena remain behind, waiting to reward future industry?’134

The award set the seal on Herschel’s reputation, and reignited the general fascination with astronomy. The discovery of the seventh planet began a revolution in the popular conception of cosmology. It was widely reported in the gazettes, journals and year books published in London, Paris and Berlin at the end of 1782. Yet although all orreries were instantly out of date, it took some time for Uranus to enter into the popular imagery and iconography of the solar system.

One of the best of the new wave of popular astronomy books was John Bonnycastle’s Introduction to Astronomy in Letters to his Pupil, which first appeared in 1786 (and went on to new expanded editions in 1788, 1811 and 1822). Bonnycastle gave the discovery of Uranus its own chapter: ‘Of all the discoveries in this science, none will be thought more singular than that which has lately been made by Dr Herschell…This is a Primary Planet belonging to the solar system, which till 13th of March 1781, when it was first seen by Dr Herschell, had escaped the observation of every other astronomer, both ancient and modern…’ Yet he still treated it as a puzzling novelty, its significance yet to be developed. ‘This discovery, which at first appears more curious than useful, may yet be of great service to astronomy…and may produce many new discoveries in the celestial regions, by which our knowledge of the heavenly bodies, and of the immutable laws that govern the universe, will become much more extended: which is the great object of the science…‘135

Bonnycastle’s book was a thoroughly Romantic production, which included a good deal of ‘illustrative’ cosmological poetry from Milton, Dryden and Young. It also sported an engraved frontispiece by Henry Fuseli. This showed the goddess of astronomy, Urania, in a diaphanous observation-dress, pointing seductively to her new star while instructing a youthful male pupil. The publisher was Joseph Johnson of St Paul’s Churchyard, also the publisher of William Blake, William Godwin and Mary Wollstonecraft; and later of Wordsworth and Coleridge.

Bonnycastle was a great friend of the philosopher Godwin, and besides including poetry to illustrate his astronomical explanations, he considered the imaginative impact of the new astronomy. The ‘Babylonian’ writers of Egypt had increased the Biblical estimate of the earth’s age from 6,000 to 400,000 years, but Bonnycastle pointed out that ‘the best modern astronomers’ had increased this to ‘not less than 2 million years’. He thought that viewing the stars through a telescope both liberated the imagination and produced a certain kind of wonder, mixed with disabling awe or terror: ‘Astronomy has enlarged the sphere of our conceptions, and opened to us a universe without bounds, where the human Imagination is lost. Surrounded by infinite space, and swallowed up in an immensity of being, man seems but as a drop of water in the ocean, mixed and confounded with the general mass. But from this situation, perplexing as it is, he endeavours to extricate himself; and by looking abroad into Nature, employs the powers she has bestowed upon him in investigating her works.’136

Uranus slowly became a symbol of the new, pioneering discoveries of Romantic science. An unfathomably larger universe was steadily opening up, and this gradually transformed popular notions of the size and mystery of the world ‘beyond the heavens’. Indeed, the very terms ‘world’, ‘heaven’ and ‘universe’ began to change their meanings. It was the psychological breakthrough that Kant had predicted in his Universal Natural History and Theory of the Heavens back in 1755: ‘We may cherish the hope that new planets will perhaps yet be discovered beyond Saturn.’137

Erasmus Darwin would eventually celebrate Herschel’s new astronomy in his poem The Botanic Garden (1791), notably in the spectacular opening section of Canto 1. The discovery of Uranus inspired Darwin to evoke many other possible ‘solar systems’, each with its own sun and planetary family, spontaneously exploding into being after an initial ‘big bang’. Here Darwin was using Newton’s celestial mechanics (based on Kepler’s three laws of planetary motion), but dramatising the new notion of an endless sequential creation as implied by Herschel. The creative cosmic force is ‘Love’ (as in the classical cosmology of Lucretius), while the Biblical God now seems content simply to initiate what is, in effect, a vast cosmological experiment, and then sit back as a passive observer.

When Love Divine, with brooding wings unfurl’d,

Call’d from the rude abyss the living World,

‘Let there be Light!’, proclaimed the Almighty Lord,

Astonish’d Chaos heard the potent word;

Through all his realms the kindling ether runs

And the mass starts into a million Suns.

Earths round each Sun with quick explosions burst,

And second Planets issue from the first;

Bend as they journey with projectile force,

In bright ellipses their reluctant course;

Orbs wheel in orbs, round centres centres roll,

And form, self-balanced, one revolving whole.

-Onward they move, amid their bright abode,

Space without bound, the bosom of their God!

To this shimmering and kinetic passage, which seems to anticipate in language the music of Haydn’s Creation (1796-98), Darwin added a long, admiring Note on ‘Mr Herschel’s sublime and curious account of the construction of the heavens’.138♣

Astronomers from all over Europe (especially France, Germany and Sweden) began to write to Herschel in Bath, asking for details about his metal specula, his high-magnification eyepieces and his observational techniques. In England there continued to be much scepticism about both his abilities and his telescopes. His replies tended to be formal, but occasionally he relaxed a little with astronomers whom he trusted, and whose skills he admired. He light-heartedly described the pains he took to set up, tune and even ‘humour’ his telescopes. He gave them a life of their own, and implied that he treated them like so many concert prima donnas (perhaps remembering La Farinelli, who had saved him at the Pump Room). To Alexander Aubert in London he wrote one of his most whimsical accounts on 9 January 1782, when enclosing his new catalogue of double stars. ‘These instruments have played me so many tricks that I have at last found them out in many of their humours, and have made them confess to me what they would have concealed, if I had not with such perseverance and patience, courted them. I have tortured them with powers, flattered them with attendance to find out the critical moments when they would act, tried them with Specula of a short and long focus, a large aperture and a narrow one. It would be hard if they had not proved kind to me at last!’139

It is striking how frequently he now compared the art of astronomical observation to learning and playing a musical instrument. To Aubert he wrote of the need to adjust each telescope individually and ‘to screw an instrument up to its utmost pitch. (As you are an Harmonist you will pardon the musical phrase.)’

Yet for some months Herschel had to continue to defend his telescopes against sceptics in the Royal Society. To the accusation that his discovery was by chance, they now added the implication that the huge powers of magnification he claimed were illusory. Particular scepticism was directed at his lens of 6,000 power, since it was calculated that a star so highly magnified would move through the viewing field of his telescope in ‘less than a second’, owing to the earth’s rotation. Therefore it would be quite impossible to observe. Herschel replied crisply that it took all of three seconds, and he could follow such a star very well.140 But to William Watson he complained that his critics evidently intended to send him ‘to Bedlam’, and wrote defensively on 7 January 1782: ‘I do not suppose there are many persons who could even find a star with my [magnifying] power of 6,450; much less keep it if they had found it. Seeing is in some respects an art, which must be learnt. To make a person see with such a power is nearly the same as if I were asked to make him play one of Handel’s fugues upon the organ. Many a night have I been practising to see, and it would be strange if one did not acquire a certain dexterity by such constant practice.’141

Watson quietly kept Banks informed of the controversy, while Banks gently temporised, suggesting that perhaps the magnifications were slightly miscalculated, but supporting Herschel against his detractors. He sent smiling presidential greetings: ‘My best Compliments to Mr Herschell, with best wishes for the Sake of Science that his nights may be as Sleepless as he can wish them himself.’142

Alexander Aubert now firmly took Herschel’s side. Thanking him for the catalogue of double stars, he remarked appreciatively on all the trouble Herschel had taken: ‘but trouble is nothing to you, and the least thing we can do in return is to…convince the world that though your discoveries are wonderful, they are not imaginary…Your great power of 6450 continues to astonish, your micrometer also…Go on, my dear Sir, with courage, mind not a few barking, jealous puppies; a little time will clear up the matter and if it lays in my power you shall not be sent to Bedlam alone, for I am much inclined to be one of the party.’143

Herschel’s next destination, as it turned out, was not Bedlam but Windsor. King George III, advised by the Astronomer Royal and the President of the Royal Society, had chosen to ignore these controversies. He summoned Herschel to court to congratulate him, but asked Banks and Maskelyne to make an independent trial of the now celebrated sevenfoot telescope at the Greenwich Observatory. On 8 May Herschel left for London, his precious telescope and folding stand perilously packed into a mahogany travel-box (’to be screwed together on the spot where wanted’), accompanied by a hastily assembled trunk of equipment including his large Flamsteed atlas (marked up by Caroline), his new catalogue of double stars (similarly written up by Caroline), ‘micrometers, tables, etc’, and rather makeshift court dress.144

At Greenwich, Maskelyne was stunned by the superior quality and light-gathering power of Herschel’s ‘home made’ mirrors. He immediately recognised that they were far more powerful than any of the official observatory telescopes, and probably than any other telescope in Europe. Maskelyne, reputed to be a jealous and illiberal man because of his supposed ill-treatment of the watchmaker John Harrison, behaved with great forthrightness and generosity to Herschel.

On 3 June 1782 Herschel wrote exuberantly to Caroline, casting aside his usual circumspect tone: ‘Dear Lina…The last two nights I have been star-gazing at Greenwich with Dr Maskelyne & Mr Aubert. We have compared our telescopes together and mine was found very superior to any at the Royal Observatory. Double stars they could not see with their instruments I had the pleasure to show them very plainly, and my [folding stand] mechanism so much approved of that Dr Maskelyne has already ordered a model to be taken from mine; and a stand to be made by it for his reflector. He is however now so much out of love with his instrument [a six-foot Newtonian] that he begins to doubt whether it deserves a new stand.’145

Banks (who had learned much about royal decorum since Tahiti) now knew that it was the perfect moment to introduce Herschel formally to the King at Windsor in May 1782. The meeting between the two Hanoverians (commoner and king, but both firmly speaking English) was a great success. Members of the King’s Hanoverian entourage had already heard of the Herschel brothers as talented musicians, and His Majesty was intrigued by the change in métier.146 King George, not yet mad, was renowned for his aphoristic remarks to his more talented subjects. To Edward Gibbon, for example, still deep in his six-volume history The Decline and Fall of the Roman Empire, he had observed archly: ‘Scribble, scribble, scribble, eh, Mr Gibbon?’ It was said that the King now murmured to Banks: ‘Herschel should not sacrifice his valuable time to crotchets and quavers.147

Herschel wrote swiftly to Caroline, with a note of growing excitement that had never previously appeared in his letters. ‘Among Opticians and Astronomers nothing is now talked of but what they call my great discoveries. Alas! This shows how far they are behind, when such trifles as I have seen and done are called great. Let me but get at it again! I will make such telescopes & see such things-that is, I will endeavour to do so.’148 In a later note, again using her intimate diminutive name, he added: ‘You see Lina I tell you all these things, you know vanity is not my foible therefore I need not fear your Censure.’149 He would not have feared his sister’s censure a decade before.

Banks was determined to find his new astronomical protégé a salary, and if possible a suitable place. This required some diplomacy, as university professorships were for mathematicians, the post of Astronomer Royal was evidently taken, and the new post of Royal Astronomer at Kew Gardens had recently been promised to another-‘a devil of a pity’. With Banks’s diplomatic nudging, the King agreed that Herschel should give up teaching music in Bath, and move to a house near Windsor, to concentrate entirely on astronomy. To achieve this, His Majesty would be pleased to create a new official post, appointing Herschel as the King’s Personal Astronomer at Windsor on a salary of £200 per annum. (This was not particularly generous, but then the Astronomer Royal received only £300.) At the age of forty-three, Herschel’s second career had burst into life.

After the very briefest consultation, Herschel, Caroline and their brother Alexander moved on 31 July 1782 to a large, sprawling house in the village of Datchet, positioned deep in the countryside between Slough and Windsor, just south of the river Thames. The house had large grass plots suitable for erecting telescopes, and several stables and outbuildings for the furnaces and the grinding and polishing equipment. An old laundry could be converted into an observation building. But the house itself had not been inhabited for several years, and was cold and damp. Caroline set about the huge task of cleaning and repairing.150

Almost immediately Herschel was commanded to bring his famous seven-foot telescope to Windsor, where it was reassembled on the terrace for everyone to view the planets. Herschel was a particular success with the three teenaged royal princesses, Charlotte, Augusta and Elizabeth. On one cloudy evening (it being an English summer) when viewing was impossible, he had the inspired idea of constructing pasteboard models of Jupiter and its four moons, and Saturn and its rings, and hanging them-illuminated by candles-from a distant garden wall on the Windsor estate. These were meticulously prepared beforehand. By ingeniously focusing down the seven-foot, he was able to show these models to the three young girls through the telescope, an early form of outdoor planetarium.151

Many other children of the new generation also grew up understanding the cosmos in a new way. Discovering the stars became a particular and special moment of self-discovery. The poet Coleridge remembered being taken out at night into the fields by his beloved father, the vicar and schoolmaster of Ottery St Mary in Devon, in the winter of 1781 to be shown the night sky. Coleridge was only eight, but he never forgot it. Perhaps the Reverend John Coleridge, a great follower of the monthly magazines (to which he sometimes contributed learned articles on Latin grammar), had recently read of Georgium Sidus. At all events, Coleridge treasured the memory of his father’s eager demonstration of the stars and planets overhead, and the possibility of other worlds: ‘I remember, that at eight years old I walked with him one evening from a farmer’s house, a mile from Ottery-& he told me the names of the stars-and how Jupiter was a thousand times larger than our world-and that the other twinkling stars were Suns that had worlds rolling round them-& when I came home, he showed me how they rolled round. I heard him with profound delight & admiration; but without the least mixture of Wonder or incredulity. For from my early reading of Faery Tales, & Genii etc etc-my mind had been habituated to the Vast.152

Such a huge, starlit prospect, inhabited by giant planets and remote classical gods, might have puzzled or alarmed a normal eight-year-old. But the striking thing is that Coleridge, who wrote many letters about his childhood and always remembered it acutely, said he felt no surprise or disbelief at all-‘not the least mixture of Wonder or incredulity’-about this revelation of the enormous scale of the universe. He felt himself already tuned to the size and mystery of the new cosmos. His Romantic sensibility-even at the age of eight-already inhabited the infinite and the inexplicable. Cosmological imagery, and especially the symbolic movement of the stars and the moon, entered deeply into his early poetry, and in a sense it came to rule the world of the Ancient Mariner and his ship.

The moving Moon went up the sky,

And nowhere did abide;

Softly she was going up,

And a star or two beside.

Her beams bemocked the sultry main,

Like April hoar-frost spread,

But where the ship’s huge shadow lay,

The charmed water burnt alway

A still and awful red.153

The prose gloss that Coleridge added to this passage almost twenty years later (1817) takes on a new resonance when compared with what we now know of Herschel’s long nights of lunar observation:

In his loneliness and fixedness he yearneth towards the journeying Moon, and the stars that still sojourn, yet still move onward; and every where the blue sky belongs to them, and is their appointed rest, and their native country and their own natural homes, which they enter unannounced, as Lords that are certainly expected and yet there is silent joy at their arrival.

The young John Keats remembered an organised game at his school in Enfield, in which all the boys whirled round the playground in a huge choreographed dance, trying to imitate the entire solar system, including all the known moons (to which Herschel had by then added considerably). Unlike Newton’s perfect brassy clockwork mechanism, this schoolboy universe-complete with straying comets-was a gloriously chaotic ‘human orrery’.

Keats did not recall the exact details, but one may imagine seven senior boy-planets running round the central sun, while themselves being circled by smaller sprinting moons (perhaps girls), and the whole frequently disrupted by rebel comets and meteors flying across their orbits. Keats was later awarded Bonnycastle’s Introduction to Astronomy as a senior school prize in 1811. Reading of Herschel, he enshrined the discovery of Uranus five years later in his great sonnet of 1816, ‘On First Looking into Chapman’s Homer’.154


Once they had moved to Datchet, Herschel and his brother Alexander started an exclusive business in the manufacture of high-quality reflector telescopes. The first five of them, all seven-foot reflectors, were ordered by King George as royal gifts, and although never fully paid for by the Crown office (they were priced at a hundred guineas each), they had the invaluable effect of making Herschel the royal telescope-maker, ‘By Appointment’. All telescopes, whatever their size, were individually constructed to order, took three or four weeks to make, and had an individual price, usually quoted in guineas. Herschel would supply them either in kit form or fully assembled in beautiful mahogany cases, with spare mirrors and a selection of eyepieces. Although every one was handcrafted, his immense energy achieved something like mass-production. Over the next decade he made 200 mirrors for the popular seven-foot telescope, 150 for the ten-foot, and eighty for the big twenty-five-foot, although not all of these were sold.155

Prices rose steadily. The renowned seven-foot telescope was usually sold in kit form for thirty guineas, but Herschel gradually raised even the kit price to a hundred guineas, the figure he quoted to the German astronomer Johann Bode in Berlin.156 Eventually a twenty-foot in kit form sold for 600 guineas. The luxury ten-foot reflector, complete with polished mahogany case, patent adjustable stand, a selection of eyepieces and a spare mirror, cost a princely 1,500 guineas.157 Indeed the more expensive models were sold mostly to German princes, and models also went to Lucien Bonaparte (Napoleon’s brother) and the Emperor of Austria.158 Probably the most expensive commercial telescope that Herschel ever made was commissioned by the King of Spain for £3,500, and delivered to the Madrid Observatory in 1806.159 Scores of Herschel’s telescopes were eventually sent all over England and Europe, and he personally delivered one on behalf of King George to the state observatory at Göttingen in 1786.160

Gradually more and more visitors began to descend on the observatory at Datchet. Caroline started to keep a neat, double-columned visitors’ book, rather as if she were recording star observations, which in a sense she was. In spring 1784 the dying Dr Johnson sent the young Susannah Thrale (Mrs Thrale’s third daughter) on a visit, advising her to cultivate an acquaintance with Herschel: ‘He can show you in the night sky what no man before has ever seen, by some wonderful improvements he has made in the telescope. What he has to show is indeed a long way off, and perhaps concerns us little, but all truth is valuable and all knowledge pleasing in its first effects, and may subsequently be useful.’161

Caroline wrote vivid accounts of their routine of all-night star observations, or ‘sweeps’.162 Herschel’s technique of ‘sweeping’ did not-as the term seems to imply-involve moving the telescope laterally, which was always a tricky operation with the bigger reflectors. Instead it was kept on the meridian, and moved slowly up and down, while the constellations turned through the field of observation as the stars moved steadily across the night sky. As this motion is caused by the earth itself rotating on its polar axis, so the telescope is effectively ‘sweeping’ the heavens like some immensely long broom, or the finger of a searchlight. By this method Herschel could progressively cover the entire night sky in a series of small strips, each covering about two degrees of arc.163 The technique was far more accurate than any other stellar observation that had ever been undertaken before in the history of astronomy. But it was also immensely slow and painstaking. A complete sweep could take several years to complete.

During this time Herschel became so familiar with every part of the sky that he could identify stellar patterns, and any new objects, with amazing speed and precision. Perhaps his musical training helped him here, as much as his painfully self-taught mathematics. As he suggested himself, he could read the night sky like a skilled musician sight-reading a musical score. Or more subtly, the brain that was trained to recognise the highly complex counterpoints and harmonies of Bach or Handel could instinctively recognise analogous stellar patternings.

Herschel became fascinated by both the physics and the psychology of the observation process itself, and later wrote some of his most fascinating papers about it. From 1782 he began to record the many physical tricks his eyes could play, and also began to study the illusions of night observation. On 13 November, while trying to identify a new double star in Orion, he dictated a careful note to Caroline:

Following 10 Orionii. I saw very distinctly double at least a dozen times pass through the whole field of view with both eyes, but was obliged to darken everything. I suspected my right eye to be tired, & know it to see objects darker. Therefore tried the left first, & saw it immediately pass thro’ the field double several times. Saw the same afterwards with the other eye…No star twinkled except Syrius, & those as low. The evening exceptionally fine for telescopes.164

The more he was challenged by professional astronomers, the more Herschel became conscious of his ‘art of seeing’, and how it needed explaining afresh. ‘The eye is one of the most extraordinary Organs,’ he repeatedly told his correspondents. Classical physiology was wrong. Visual images did not simply fall upon the optic nerve, in the same sense that they fell upon a speculum mirror. The eye constantly interpreted what it saw, especially when using the higher powers of magnification. The astronomer had to learn to see, and with practice (as with a musical instrument) he could grow more skilful: ‘I remember a time when I could not see with a power beyond 200, with the same instrument which now gives me 460 so distinct that in fine weather I can wish for nothing more so. When you want to practise seeing (for believe me Sir,-to use a musical phrase-you must not expect to see at sight or a livre ouvert) apply a power something higher than what you can see well with, and go on increasing it after you have used it for some time.’165

Caroline later assembled an index of all Herschel’s remarks on practical observation. Under ‘Trials of Different Eyes and Seeings’ she listed such topics as the distortion effect of ‘looking long at an object etc’, the need to progress from lower to higher powers of magnification, the fact that ‘different eyes judge differently of [the same] colours’, that ‘eyes tire’ without the observer noticing, and that ‘we see things always smaller at first, when difficult to be seen’.166

Under another heading, ‘Airs and Situations’, she listed the particular locations and atmospheric conditions which affected a telescope. These were not always self-evident. The atmosphere itself had ‘prismatic powers’, and distortions could be produced by ‘field breezes’, viewing ‘over the roof of a house’, or standing ‘within 6 or 8 feet of a door’. Surprisingly, because of thermal ripples rising from the ground, ‘evenings tho’ apparently fine, are not always good for viewing’. By contrast, ‘moist air was favourable’, and damp or rain, even certain kinds of fog, were ‘no hindrance to seeing’. It was possible to observe in conditions of severe frost, or even falling snow, provided the mirrors were kept clear of ice.167

Caroline gave the term ‘sweeping’ a certain domestic familiarity, so that in her letters she sometimes implies she is a sort of celestial housekeeper, brushing and dusting the stars to keep them in a good state for her brother, a sort of heavenly Hausfrau. But perhaps she also had deeper feelings about the cosmos she was now discovering. It was no longer a mere hobby to please him. Once they had moved to Datchet, in the summer of 1782 Herschel began to train her more carefully in observation techniques, so she could become a genuine ‘assistant-astronomer’. By way of encouragement he built her a special lightweight sweeper, consisting of ‘a tube with two glasses’ (i.e. a traditional refractor), and instructed her ‘to sweep for comets’.

Initially she found working on her own in the dark rather daunting. ‘I see from my Journal that I began August 22nd 1782, to write down and describe all remarkable appearance I saw in my sweeps, which were horizontal. But it was not till the last two months of the same year that I felt the least encouragement to spend the star-light nights on a grass-plot covered with dew or hoar frost, without a human being near enough to be within call.’168 Besides, at this early stage Caroline knew ‘too little of the real heavens to be able to point out every object so as to find it again without losing too much time by consulting the Atlas’. As all novice astronomers find, stars move disconcertingly rapidly through a telescopic field of vision, even that of a low-powered telescope, and can easily slip away in the few moments spent consulting a star chart and then readjusting one’s eyes to night vision. (Night vision can take as long as thirty minutes to establish its full sensitivity.)

Clearly things were better for Caroline when Herschel was on hand in the garden, and not away at Windsor doing royal demonstrations. ‘All these troubles were removed when I knew my brother to be at no great distance making observations with his various instruments on double stars, planets etc, and I could have his assistance immediately when I found a nebula, or cluster of stars.’ In this first year Caroline found no comets, and only succeeded in identifying fourteen of the hundred or so known nebulae. She was too often interrupted by Herschel’s imperious shout, when he wanted her to write down some new observation made with the large twenty-foot.169

Such teamwork was essential to the sweeping procedure that the Herschels developed. As William made his observations, he would call out precise descriptions of what he saw (with special attention to double stars, nebulae or comets). He would give magnitudes, colour and approximate distances and angles (using a micrometer) from other known stars within the field of view. Standing below him in the grass, and later sitting at a folding table, Caroline would meticulously note all this data down, using pen and ink and a carefully shrouded candle lantern, and consulting their ‘zone clock’ (a clock using a time scale related to the position of the stars, rather than the sun). Alexander Aubert would later give them a magnificent Shelton clock, with compensated brass pendulum, as a contribution to their work.170

With Herschel, this was not tranquil or contemplative work, as might be supposed. Caroline would ‘run to the clocks, write down a memorandum, fetch and carry instruments, or measure the ground with poles etc etc of which something of the kind every moment would occur’.171Sometimes she would call back questions, asking for further clarifications. Most importantly she would note the exact time of each observation, using the special zone clock, which would give a precise position as each object rotated through the meridian. By this method, at no point would William have to compromise his night vision by looking at a lit page and taking his own notes.

Herschel described their sweeping methods in a paper published in April 1786, ‘One Thousand New Nebulae’. Crucial to his technique was that he did not have to take his eye away from the lens, but could ‘shout out’ his observations while his assistant wrote them down and ‘loudly repeated’ them back to him. This had ‘the singular advantage’, as he put it, ‘that the descriptions were actually writing and repeating to me while I had the object before my eye, and could at pleasure correct them’. The distinct tone of military command was emphasised by the fact that nowhere in this paper did Herschel mention that his assistant was Caroline.172

Standing under a night sky observing the stars can be one of the most romantic and sublime of all experiences. But the Herschels’ sweeps were fantastically prolonged and demanding. In clear weather, they would often go on for six or seven hours without a break. They began at eleven at night, and often did not go to bed before dawn, in a mixed state of exhaustion and euphoria. Both slept till midday, and the house had to be kept quiet most of the morning, although Caroline often seems to have been up early, drinking coffee and writing up the night’s observations in long, minute columns of figures: a sort of double book-keeping which she often referred to as ‘minding the heavens’.

Observations and note-making required dogged precision and absolute concentration. It could be chill even in summer, and in winter the frost covered the grass around them, and the wind moaned through the trees. (Nevil Maskelyne had a special woollen one-piece observation suit made for him at Greenwich, with padded panels that made him look like a premonition of the Michelin Man.) Herschel took to rubbing his face and hands with raw onions to keep out the cold. When Banks came down to join them he sometimes brought oversize shoes so he could wear half a dozen pairs of stockings inside them. Caroline layered herself in woollen petticoats. Frequently it was so cold that films of ice formed on the telescope mirrors, the ink clotted in the well, and frozen beads blunted the tip of Caroline’s quill.173

It could also be dangerous. Caroline wrote: ‘I could give a pretty long list of accidents of which my Brother as well as myself narrowly escaped of proving fatal for observing with such large machineries, where all around is in darkness [and] is not unattended with danger; especially when personal safety is the last thing with which the mind is occupied at such times.’174 The winter of 1783 was especially harsh. On one night in November that year, when William was mounted high up on the crossbar of his twenty-foot reflector, the wind almost blew him off, and when he hastily clambered down the rickety structure (’the ladders had not even the braces at the bottom’), the entire wooden frame collapsed around him; workmen had to be called to release him from the wreckage of spars.175

On 31 December 1783, New Year’s Eve, over a foot of snow had fallen, and the sky was overcast. William however postponed celebrations, and insisted on the last sweep of the year. Caroline gives the impression that he was particularly impatient, and perhaps shouting at her more than usual. ‘About 10 o’clock a few stars became visible, and in the greatest hurry all was got ready for observing. My Brother at the front of the Telescope [was] directing me to make some alterations in the lateral motion.’ As she hurried round the base of the telescope, ‘having to run in the dark on ground covered foot deep in melting snow’, she slipped and tripped over a hidden wooden stake. These stakes were used to peg down the telescope frame with guy ropes, and had large iron hooks facing vertically upwards, ‘such as butchers use for hanging their joints on’.

Caroline painfully recounted what followed. ‘I fell on one of these hooks which entered my right leg about six inches above the knee. My brother’s call-make haste!-I could only answer by a pitiful cry-I am hooked!’ She was impaled, like a fish on a barb, and could not move. Herschel was still high up on the observation platform, in complete darkness, and did not immediately realise what had happened. It seems he continued to call down through the dark, ‘Make haste!’, while Caroline continued to gasp back in agony, ‘I am hooked!176

Finally he grasped the situation, and called for help from the assistant who had been adjusting the telescope frame. ‘He and the workman were instantly with me, but they could not lift me without leaving near 2 oz. of my flesh behind. The workman’s wife was called but was afraid to do anything.’ Caroline was carried back to the house, but astonishingly no doctor was called. She bandaged the wound herself, retired to bed, and proudly recorded that she was back on telescope duties within a fortnight. It seems that the extreme cold had an antiseptic effect on the large, open wound, and prevented fatal gangrene.

No doubt it was characteristic of Caroline to treat this wound lightly, and not make any fuss. Yet there is an uneasy sense throughout her account that William did not treat her with sufficient tenderness or care: ’I was obliged to be my own surgeon by applying acquabaseda and tying a kerchief about it for some days.’ The local Windsor physician, Dr James Lind, only heard about the accident a week later, ‘and brought me ointment and lint and told me how to use it’. The deep wound did not heal easily, but there is still no mention of William’s concern at any point. Eventually Dr Lind was called back to Datchet in early February 1784. ‘At the end of six weeks I began to have some fears about my poor Limb and had Dr Lind’s opinion, who on seeing the wound found it going on well; but said, if a soldier had met with such a hurt he would have been entitled to 6 weeks nursing in a hospital.’177 It is curious that Dr Lind compared Caroline to someone in military service, and it is hard to overlook a certain note of reproach in his words.

Caroline surely intended some irony when she added in the Memoir: ‘I had however the comfort to know that my Brother was no loser through this accident for the remainder of the night was cloudy and several nights afterwards afforded only a few short intervals favourable for sweeping, and until 16 January before there was any necessity for exposing myself for a whole night to the severity of the season.’

The wound had largely healed by the summer, but it would later return to give her chronic pain in old age. Her pitiful cry-‘I am hooked!’-is curiously symbolic of her relations with her brilliant, domineering brother at this period, at a time when he was obsessed by his astronomical ideas to the exclusion of all else. Including, it might seem, his sister’s well-being; although we have only her word for this.178

It is hardly surprising that Herschel was a little distracted. In 1784 and 1785 he drew together his most radical ideas about the cosmos, and published two revolutionary papers in the Royal Society’s Philosophical Transactions. These completely transformed the commonly held idea of our solar system being surrounded by a stable dome of ‘fixt stars’, with a broad ‘galaxy’ or ‘via lactae’ (meaning a ‘path or stream of milk’) of smaller, largely unknown stars spilt across it, roughly from east to west. This was a celestial architecture or ‘construction’, inspired fundamentally by the idea of a sacred temple, which had existed from the time of the Babylonians and the Greeks, and had not seriously been challenged by Flamsteed or even by Newton.179

‘An Investigation of the Construction of the Heavens’, published in June 1784, quietly set out to change this immemorial picture. It was based on all Herschel’s ceaseless telescope observations, relentlessly pursued with Caroline over two years, with his new twenty-foot reflector telescope. He had identified 466 new nebulae (four times the number recently confirmed by Messier), and for the first time suggested that many, if not all, of these must be huge independent star clusters or galaxies outside our own Milky Way.180

This led him on to propose a separate, three-dimensional shape to the apparent flat ‘milk stream’ of the Milky Way. His proposal was based on his new method of ‘gauging’ the number of stars in any direction as seen from the earth, and then deducing from the different densities observed the likely shape of this galactic star cluster as it would be seen looking ‘inwards’ from another galaxy. This was a daring mixture of observation and speculation. Herschel’s first galactic diagram appeared like a curious oblong box or tilting parallelogram of stars.181 But his later calculations produced the now-familiar discus shape of the Milky Way, with its characteristic arms spinning out into space, and the slight bulge of stars at its centre.182 He was never sure where the solar system was located in the galaxy, and at one point observed that its overall shape was relative, depending on the view as seen by ‘the inhabitants of the nebulae of the present catalogue…according as their situation is more or less remote from ours‘.183

In the second paper, called simply ‘On the Construction of the Heavens’ (1785), Herschel began to develop these ideas into a startling new ‘natural history’ of the universe. He opened by arguing that astronomy required a delicate balance of observation and speculation. ‘If we indulge a fanciful imagination and build worlds of our own…these will vanish like Cartesian vortices.’ On the other hand, merely ‘adding observation to observation’, without attempting to draw conclusions and explore ‘conjectural views’, would be equally self-defeating.184

His own conjecture would be radical. The heavenly ‘construction’ was not something architecturally fixed by the Creator, but appeared to be constantly changing and even evolving, more like some enormous living organism. His telescopes seemed to show that all gaseous nebulae were actually ‘resolvable’ into stars. They were not amorphous zones of gas left over from the Creation. They were enormous star clusters scattered far beyond the Milky Way, and were dispersed throughout the universe as far as his telescopes could penetrate. The nebulae themselves were active. Their function seemed to be that of constantly forming new stars out of condensing gas, in a process of continuous creation. They were replacing stars which were lost.

Herschel found a memorable phrase for this astonishing speculation: ‘These clusters may be the Laboratories of the universe, if I may so express myself, wherein the most salutary remedies for the decay of the whole are prepared.’185 He also pursued the possibility that some nebulae may be ‘island universes’ outside the Milky Way, thereby hugely increasing the sense of the actual size of the cosmos. Among these was the beautiful nebula in Andromeda, ‘faintly red’ at the centre. By 1785 his nebulae count had risen to well over 900. They appeared ‘equally extensive with that which we inhabit [the Milky Way]…yet all separate from each other by a very considerable distance’.186 He picked out at least ten ‘compound nebulae’ which he considered larger and more developed than the Milky Way, and imagined the star-cluster view of our own galaxies from theirs. ‘The inhabitants of the planets that attend the stars that compose them must likewise perceive the same phenomena. For which reason they may also be called Milky Ways by way of distinction.’187

As Kant had speculated, the cosmos might be infinite, whatever that might mean. Though Herschel’s estimates of cosmological distances were much too small by modern calculation, they were outlandishly, even terrifyingly, vast by contemporary standards. Beyond the visible parts of our own Milky Way, he estimated that a huge surrounding ‘vacancy’ of deep space existed, ‘not less than 6 or 8 thousand times the distance of Sirius’. He admitted that these were ‘very coarse estimates’. The implications seemed clear, though they were cautiously expressed in his paper: ‘This is amply sufficient to make our own nebula a detached one. It is true, that it would not be consistent confidently to affirm that we were an Island Universe unless we had actually found ourselves everywhere bounded by the ocean…A telescope with a much larger aperture than my present one [twelve inches], grasping together a greater quantity of light, and thereby enabling us to see further into space, will be the surest means of completing and establishing the argument.’188

The dramatic implications of these ideas were soon picked up by journalists and popularisers. The following year Bonnycastle assessed the situation in the first edition of his Introduction to Astronomy: ‘Mr Herschel is of opinion that the starry heaven is replete with these nebulae, and that each of them is a distinct and separate system, independent of the rest. The Milky Way he supposes to be that particular nebula in which our sun is placed; and in order to account for the appearance it exhibits, he supposes its figure to be much more extended towards the apparent zone of illumination than in any other direction…These are certainly grand ideas, and whether true or not, do honour to the mind that conceived them.’189

Also contained in Herschel’s revolutionary paper of 1785 were the seeds of a new, long-term project. He was planning the building of a monster forty-foot telescope, with a four-foot mirror. This would be the biggest and most powerful reflector in the world. With this he believed he could resolve once and for all the problem of the nebulae-whether they were other galaxies far beyond the Milky Way, or merely gas clouds within it. He would also have a better chance of establishing the true distance of the stars, through the measurement of stellar parallax. Above all he believed he would be able to understand how the stars were created, and whether the whole universe was changing or evolving according to some definite law or plan. Finally, he believed he might establish if there were observable signs of extraterrestrial life, a discovery which would have enormous impact on philosophical and even theological beliefs.

There was one other small, but revolutionary, departure in his 1785 paper. For the first time William Herschel carefully credited Caroline in print with a small ‘associate nebula’ in Andromeda. It was a previously unknown cluster ‘which my Sister discovered on August 27 1783 with a Newtonian 2 foot sweeper’. It was not in Messier’s annual catalogue La Connaissance des Temps, so this was Caroline Herschel’s first new addition to the universe.190

 Caroline eventually wrote out two versions of this memoir, the first in summer 1821, when she was seventy, and the second in 1840. She also destroyed two sections of the original record which she did not want read by other family members. A composite version was edited by her great-niece, Mrs John Herschel, and published by Murray in 1769. The manuscript still exists in the private collection of John Herschel-Shorland. The individual Memoirs have been meticulously published by Michael Hoskin, as Caroline Herschel’s Autobiographies (2003). William wrote a ‘Memorandum of my Life’ when he was nearly sixty, but this was a sort of professional CV for fellow scientists, comparatively short and characteristically reserved (Herschel, Scientific Papers 1, p.xiii). For full details see the Bibliography.

 Three of William Herschel’s works are currently available on CD. They are his Oboe Concertos in C major and E-flat major, and his Chamber Symphony in F major (Newport Classics, Rhode Island, USA, 1995). They are notable for their light musical touch and fine, sprightly melodic lines, sometimes with a certain melancholy in the slower passages. The rapid, complex orchestration around the solo oboe in the concertos is handled with great confidence, and suggests Herschel’s ability to manage patterns and counterpoint. This was a conceptual skill which he seemed to transfer (visually) to the patterning of stars and constellations. He moved from earthly music to the music of the spheres.

 A typical brass eighteenth-century orrery showed the sequence of six known planets: Mercury, Venus, Earth, Mars, Jupiter (with moons) and Saturn (with rings) orbiting around a central sun (sometimes operated by clockwork and illuminated by candles). Flamsteed showed all constellations-such as Herschel’s early favourites Orion, Andromeda and Taurus-against mythological engravings of their signs: the Hunter, the Goddess, the Bull. His Atlas Coelestis catalogued 3,000 stars; the modern Hubble telescope has identified some nineteen million. But the presentation of the night sky as a curved dome of mythological constellations is still quite usual, as for instance in the magnificently restored curved ceiling of Grand Central Station, New York.

 The use of horse-dung moulds for casting metal mirrors continued well into the twentieth century, with the 101-inch mirror of the Mount Wilson telescope in California, cast in Paris in 1920 and eventually used by Edwin Hubble to confirm Herschel’s theories about the nature and distance of galaxies in 1922. See Gale Christianson, Edwin Hubble: Mariner of the Nebulae (1995). Precision was never easy to obtain: the mirror of the modern orbiting Hubble Space Telescope was found to be two micrometres too flat at the edges, an error which cost $1.5 billion to correct in 1992.

 In describing the rebel angel’s enormous glowing shield, Milton contrives in Paradise Lost a beautiful reference to Galileo’s refractor telescope and the view he achieved of the moon.

…The broad circumference

Hung on his shoulders like the Moon, whose orb

Through optic glass the Tuscan artist views

At evening from the top of Fiesole.

Or in Val d’Arno, to descry new lands,

Rivers, or mountains in her spotty globe.

    (Paradise Lost, Book I, lines 288-. See also

          Book III, lines 589-, and Book 5, 262-)

Milton here includes Galileo’s confirmation of an imperfect, ‘spotty’ globe, as described in his famous treatise The Starry Messenger (1610). His observations of rugged lunar mountains and irregular craters proved that not all celestial objects were perfect, and so the theologians were wrong about the nature of God’s creation (as well as about the movement of the earth around the sun). More subtly, Milton puts forward the notion of the moon as the earth’s cosmic shield, battered by many warlike blows from meteors. A modern poet might assign that task to Jupiter. As a young man Milton claimed to have met Galileo in 1638, during his tour of Italy, and discussed the new cosmology. ‘There it was that I found and visited the famous Galileo, grown old, a prisoner to the Inquisition, for thinking in astronomy otherwise than the Franciscan and Dominican licensers thought’-John Milton, Areopagitica (1644).

 The Great Andromeda galaxy, now classified as M.31, is 2.8 billion light years away, part of the laconically named ‘Local Group’ of galaxies, which includes our Milky Way. The Orion nebula, M.42, hangs just below the three stars of Orion’s belt, and is a gaseous star-cluster within our own galaxy, a mere 1.6 thousand light years away, sometimes known as the Sword of Orion. The M. numbers were assigned by Herschel’s contemporary, the Parisian astronomer Charles Messier, in an annual publication known as La Connaissance des Temps. His catalogue for 1780 held sixty-eight deep-sky objects. No astronomer yet had the least idea of the enormous distances involved, so huge that they cannot be given in terms of conventional ‘length’ measurement at all, but either in terms of the distance covered by a moving pulse of light in one year (‘light years’), or else as a purely mathematical expression based on parallax and now given inelegantly as ‘parsecs’. One parsec is 3.6 light years, but this does not seem to help much. One interesting psychological side-effect of this is that the universe became less and less easy to imagine visually. Stephen Hawking has remarked, in A Brief History of Time (1988), that he always found it a positive hindrance to attempt to visualise cosmological values.

 As with road directions, a diagram is a much better way to explain parallax than a written sentence. But it is interesting to try. Parallax is basically a trigonometrical calculation applied to the heavens. Stellar parallax is a calculation which is obtained by measuring the angle of a star from the earth, and then measuring it again after six months. The earth’s movement during that interval provides a long base line in space for triangulation. So the difference in the two angles of the same star (the parallax) after six months can be used in theory to calculate its distance. In fact single stars are so far away that they did not provide sufficient parallax to be measured with the techniques available at the time. Herschel thought that double stars might provide a more obvious parallax, by triangulating their movements against each other, as observed over six months from earth. In fact no sufficient parallax was observed until the nineteenth century, when Thomas Henderson measured the distance to the nearest star, Alpha Centauri, as 4.5 light years in 1832, and the German astronomer Friedrich Bessel measured the distance to 61 Cygni as 10.3 light years in 1838. As both published their results in 1838, there was a priority dispute. The first galactic distances were established by Edwin Hubble, using the celebrated ‘red-shift’ method in the 1920s. It is intriguing that towards the end of his career Hubble thought that ‘red-shift’ might be less reliable than he had originally supposed, and galactic distances are still an area of dispute, although the ‘age’ of the entire universe is currently agreed at 13.7 billion years. Andromeda, incidentally, is ‘blue-shifted’, and therefore approaching our Milky Way, with which it will eventually collide-or cohabit.

 Young, in Night Thoughts, also imagined an infinitely distant planet with extraterrestrial inhabitants, as if it were some remote Pacific island, not unlike Tahiti perhaps:

Canst thou not figure it, an Isle, almost

Too small for notice in the Vast of being;

Severed by mighty Seas of unbuilt Space

From other Realms; from ample Continents

Of higher Life, where nobler Natives dwell.

     (Edward Young, Night Thoughts on Life,

           Death and Immortality,

                    ‘Night IX, and Last’)

 This question bears on the whole nature of science history and biography. Michael Hoskin has suggested in his essay ‘On Writing the History of Modern Astronomy’ (1980) that most histories of science continue to be ‘uninterrupted chronicles’, which run along ‘handing out medals to those who “got it right”’. They ignore the history of error, so central to the scientific process, and fail to illuminate science as a ‘creative human activity’ which involves the whole personality and has a broad social context-Journal for the History of Astronomy 11 (1980). To this one might add that Romanticism introduced three important themes into science biography. First, the ‘Newton syndrome’, the notion of ‘scientific genius’, in which science is largely advanced by a small number of preternaturally gifted (and usually isolated) individuals. Second, the existence of the ‘Eureka moment’, in which great discoveries are made without warning (or much preparation) in a sudden, blazing instant of revelation and synthesis. Third, the ‘Frankenstein nightmare’, in which all scientific progress is really a disguised form of destruction. See Thomas Söderqvist (ed.), The Poetics of Scientific Biography (2007).

 The naming of the new planet was much disputed, and was not generally agreed until the mid-nineteenth century. Johann Bode, the editor of the authoritative Berlin Astronomical Yearbook, which quickly popularised the name ‘Uranus’, urged that a single name from classical mythology, with no national overtones, was required. With impeccable Prussian logic he pointed out that in Greek mythology Saturn (Kronos) was the father of Jupiter (Zeus), and Uranus (the Greek sky god) was the father of Saturn. It is so recorded in his great Uranographia (1801), which became the most influential celestial atlas of the early nineteenth century, replacing Flamsteed’s and cataloguing some 15,000 naked-eye stars.

 It was also the first planet that was not easily visible and distinctive to the naked human eye (by colour, shape or position), and indeed it is quite frustrating to attempt to find with modern binoculars. Its presence was therefore curiously remote and mysterious, emphasising the largeness and strangeness of the new solar system (now doubled in size), but also breaking up the old, affectionate feeling for a much-loved planetary family. It is arguable that Uranus has still not fully entered into the popular mythology of the solar system, a difficulty not helped by the awkward pronunciation of its name in English, which worked better when given to the metal uranium in 1789. Herschel’s son John tried to remedy this by giving Uranus’s-try saying that!-two moons the feathery Shakespearean names of Titania and Oberon, from A Midsummer Night’s Dream.

 The Botanic Garden was the best-selling long poem in English throughout the 1790s, after which its popularity suddenly declined, probably because its science was thought to be too materialist and ‘French’. It was the first poem which presented itself in terms of a moving, ‘photographic’ image of the world: ‘Gentle Reader…Here a Camera Obscura is presented to thy view, in which are lights and shade dancing on a white canvas, and magnified into apparent life!-if thou art perfectly at leisure for such trivial amusement, walk in and view the WONDERS of my ENCHANTED GARDEN.’ Darwin’s ‘antique’ prose style in this Prologue was an ironic foil to the dense, plain, highly informative manner of his scientific footnotes. Together these notes added up to a remarkable survey of the current state of the physical sciences in 1790.

 Moon and star imagery recurs in Coleridge’s poetry throughout his life. One of his earliest known poems, ‘To the Autumnal Moon’, was a sonnet written at the age of sixteen from the lead rooftop of his London school. Many of his great West Country poems, such as ‘Frost at Midnight’ (1798), may be said to be suffused with moonlight. Greta Hall, where Coleridge lived at Keswick, was an old observatory, and from its leads he frequently recorded the state of moon, stars and the night sky, as well as his own little boy Hartley’s comments on them. His famous poem ‘Dejection’ (1802) begins with the image of the ‘winter-bright’ new moon, with ‘the old Moon in her lap’, presaging a storm. When later living alone at Malta, he used a naval telescope to observe the moon and stars, and wrote many notebook entries about his inexplicable instinct to worship the moon (1805). Even such a late poem as ‘Limbo’, probably written at Highgate, dramatises himself as an old man gazing up at the moon in a garden. He is blind-‘a statue hath such eyes’-yet mysteriously he can still sense the moonlight pouring down on him like a benediction:

He gazes still-his eyeless face all eye-As

‘twere an organ full of silent sight,

His whole face seemeth to rejoice in light!

               (Coleridge, Selected Poems,

                   Penguin Classics, p.214)

These seem to me three of the most mysterious, moonstruck lines that Coleridge ever wrote. Perhaps he was imagining himself transformed into a sort of human telescope.

 It can also be oddly terrifying. A hundred years later, Thomas Hardy took up amateur astronomy for a new novel, and in his description of Swithin and Lady Constantine sharing a telescope in Two on a Tower (1882) he captured something of the metaphysical shock of the first experience of stellar observation. ‘At night…there is nothing to moderate the blow which the infinitely great, the stellar universe, strikes down upon the infinitely little, the mind of the beholder; and this was the case now. Having got closer to immensity than their fellow creatures, they saw at once its beauty and its frightfulness. They more and more felt the contrast between their own tiny magnitudes and those among which they had recklessly plunged, till they were oppressed with the presence of a vastness they could not cope with even as an idea, and which hung about them like a nightmare.’ My own first experience with a big telescope, the ‘Old Northumberland’ at Cambridge Observatory, an eleven-inch refractor built in 1839, left me stunned. We observed a globular star cluster in Hercules, a blue-gold double star, Beta Cygni, and a gas cloud nebula (whose name I forgot to record, since it appeared to me so beautiful and malignant, according to my shaky notes like ‘an enormous blue jellyfish rising out of a bottomless black ocean’). I think I suffered from a kind of cosmological vertigo, the strange sensation that I might fall down the telescope tube into the night and be drowned. Eventually this passed. The great Edwin Hubble used to describe an almost trance-like, Buddhist state of mind after a full night’s stellar observation at Mount Wilson in California in the 1930s. See Gale Christianson, Edwin Hubble (1995).

 Dr James Lind (1736-1812) was no ordinary physician. A Fellow of the Royal Society, he had been invited to accompany Captain Cook on his second voyage round the world, but instead visited Iceland with Banks, and later voyaged to China. Deeply read in classical sciences-an expert on Pliny and Lucretius-he became a physician to the royal household, and taught modern sciences part-time at Eton. He was renowned for his eccentricity and kindness. One of his last pupils was Percy Bysshe Shelley, who was delighted by his radical talk of Franklin, Lavoisier, Herschel, Davy and Godwin. Shelley made Dr Lind the scientific teacher-sage of two of his longer poems of 1817, ‘Prince Athanese’ and ‘The Revolt of Islam’. He later told Mary Shelley: ‘This man is exactly what an old man ought to be. Free, calm-spirited, full of benevolence, and even youthful ardour: his eye seems to burn with supernatural spirit beneath his brow, shaded by his venerable white locks…I owe that man far, ah! far more than I owe to my father.’ See Richard Holmes, Shelley: The Pursuit (1974). Young Dr Lind was clearly the sort of man who would have admired Herschel, but he also greatly sympathised with Caroline.

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