Читать книгу The Age of Wonder: How the Romantic Generation Discovered the Beauty and Terror of Science - Richard Holmes - Страница 24

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