The Age of Wonder

by Richard Holmes

  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 In many ways William was quite withdrawn — enthusiastic and talkative in the mornings, but remote in the evenings after any guests had departed.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 res
entful. 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 nineteenth-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 5½ 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 star
s’.

  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’.