The Age of Wonder: How the Romantic Generation Discovered the Beauty and Terror of Science

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.

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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.

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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.’

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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.

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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.

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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’.

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8

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.

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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.

(#litres_trial_promo) 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.

(#litres_trial_promo) 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.

(#litres_trial_promo) 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.

(#litres_trial_promo) 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.

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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.’

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Caroline wrote vivid accounts of their routine of all-night star observations, or ‘sweeps’.

(#litres_trial_promo) 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.

(#litres_trial_promo) 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.

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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.’

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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’.

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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.

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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.’

(#litres_trial_promo) 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.)