5. The Age of Wonder, by Richard Holmes, pp. 114-143

Herschel on the Moon, 8; Balloonists in Heaven, 1-6

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Herschel and his brother Alexander became telescope manufacturers, starting with the five seven-foot reflectors they made for George III as royal gifts. Mirror-making remained hand-crafted, but in the course of a decade they turned out 200 mirrors for the seven-foot telescopes, 150 for the ten-foot, and eighty for the twenty-five-foot telescopes. Their customers were wealthy, and included German princes as well as Napoleon Bonaparte's brother Lucien, the Emperor of Austria, and the King of Spain, who commissioned one for the Madrid Observatory in 1806 that cost £3,500.

Herschel's celebrity attracted visitors to the observatory at Datchet. Samuel Johnson urged Susannah Thrale to visit: "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."

Despite visitors and manufacturing orders, he continued his observations, developing a technique of "sweeping" the sky that consisted of moving "slowly up and down, while the constellations turned through the field of observation as the stars moved steadily across the night sky." It was a highly accurate technique that was also very slow: "A complete sweep could take several years to complete." Herschel's familiarity with the sky, which he could read "like a skilled musician sight-reading a musical score," helped him spot any anomalies in his observations. He also began to write about the process of observation itself, including comments on the nature of the eye.

Caroline compiled his remarks on practical observation. After the move to Datchet in 1782, he began to train her even more into an "assistant-astronomer," responding to William's "imperious shout" whenever he wanted her to write down a new observation. She was expected to respond with military precision to his instructions, and her work was essential: "at no point would William have to compromise his night vision by looking at a lit page and taking his own notes." It was cold and demanding work. "They began at eleven at night, and often did not go to bed before dawn, in a mixed state of exhaustion and euphoria.... Herschel took to rubbing his face and hands with raw onions to keep out the cold.... Caroline layered herself in woollen petticoats."

There were also risks: In the harsh winter of 1783, William was almost blown off of the scaffolding that held his twenty-foot reflector, and the frame collapsed on him so that he had to be rescued from underneath it. In December of that year, Caroline was running to record one of William's observations, tripped on one of the stakes that held the guy ropes for the scaffolding, and impaled herself on the iron hook on top of the stake. It "entered my right leg about six inches above the knee," she wrote later, and the workmen couldn't remove her from the hook "without leaving near 2 oz. of my flesh behind." But they didn't call the doctor: She bandaged the wound herself and was back at work two weeks later. "It seems that the extreme cold had an antiseptic effect on the large, open wound, and prevented fatal gangrene." A week after the accident, Dr. James Lind inspected the wound and prescribed an ointment for it. (Lind was one of Shelley's favorite teachers at Eton.) Though the wound finally healed by summer, Caroline suffered pains from it in old age.

In 1784 and 1785, Herschel "drew together his most radical ideas about the cosmos, and published two revolutionary papers in the Royal Society's Philosophical Transactions." He challenged the idea of a firmly fixed cosmos, and from his study of nebulae "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." As for the Milky Way, "his later calculations produced the now-familiar discus shape ... with its characteristic arms spinning out into space, and the slight bulge of stars at its centre." In "On the Construction of the Heavens," he made the radical observation that "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 assertions had the effect of "hugely increasing the sense of the actual size of the cosmos."

He began to plan the construction of a forty-foot telescope with a four-foot mirror. And in his 1785 paper for the first time credited Caroline in print as the discoverer of "a small 'associate nebula' in Andromeda."

Meanwhile, as the British were surging ahead in astronomy, the French were making their own advances -- in ballooning. Banks heard about what they were up to in 1783 from Benjamin Franklin, who was a member of the Royal Society as well as the American ambassador to France. The French, he reported, were experimenting with lofting giant paper bags made by a paper manufacturer, Joseph Montgolfier. And then a member of the Académie des Sciences, Alexandre Charles, took things a step further by inflating a silk bag, six feet in diameter, that floated from the Champs de Mars across the Seine and drifted fifteen miles away from Paris before it burst. "This was a distance which a horseman could barely a horseman could barely cover in an hour." Charles's balloon had been filled with a newly discovered gas known as "inflammable air."

Montgolfier recovered from Charles's triumph by sending up a hot-air balloon with a wicker basket that contained a sheep, a duck, and a cockerel. It stayed in the air for seven minutes and the animals returned to earth safely. The logical next step was to send up a human being. Banks was skeptical about the experiments but recognized that they could lead to something useful, such as a "flotation device" that would make carriages and wagons lighter so that horses could pull them faster. "This aptly suggests how difficult it was, even for a trained scientific mind like Banks's, to imagine the true possibilities of flight in those early days."

The "inflammable air" that Charles had used to fill his balloon had been discovered by the English chemists Henry Cavendish and Joseph Priestley. But it was the French chemist Anton Lavoisier who repeated and refined their experiments, producing the gas from iron filings combined with sulfuric acid. He named the product "hydrogen." The Montgolfier brothers, Joseph and Étienne, followed developments in chemistry because of their paper-making business, so when they heard about this lighter-than-air gas, they speculated about using it to fly paper bags. "As early as 1782, Joseph had humorously suggested the theoretical possibility of flying an entire French army into Gibraltar, and seizing it from the English."

The Montgolfiers' first manned flight

The trouble with hydrogen is that "it was slow and dangerous to produce, potentially explosive, and easily escaped from containers made of silk or animal bladders." Hot air was easy to produce and could be contained within silk and paper -- Joseph Montgolfier said he "discovered the principle of hot air by watching his wife's chemise inflating when she hung it over the hearth to dry." The Montgolfiers first large hot air balloon, launched on June 5, 1783, was thirty feet high and 110 feet in circumference. It contained 22,000 cubic feet of hot air, rose to 60,000 feet and stayed up for ten minutes.

A twenty-nine-year-old doctor named Jean-François Pilâtre de Rozier persuaded the Montgolfiers to let him be the "test pilot" in their first manned flight on November 21, 1783. The balloon was seventy feet tall, powered by a brazier burning straw, and had a circular gallery instead of a basket for the passengers. There had to be two of them, one on either side, to balance the balloon. Pilâtre de Rozier's "co-pilot" was the Marquis d'Arlandes, an infantry major. The flight lasted twenty-seven minutes and took them across the Seine.

The launch of Alexandre Charles's hydrogen balloon

But although this was the first manned flight for the record books, the one made ten days later by Alexandre Charles is more significant for its technical breakthroughs. It was a hydrogen balloon whose silk skin had been treated with rubber. It had a valve at the top of the balloon through which the gas could be vented, and ballast bags filled with sand that could be jettisoned to control the balloon's ascent. He and an assistant, M. Robert, went up from the Tuileries Gardens on December 1, 1783.  Benjamin Franklin watched the ascent through a telescope. The flight lasted two hours and traveled twenty-seven miles. When they landed, Charles asked Robert to get out of the basket first, but the release of his weight sent the balloon aloft again, traveling to 10,000 feet in just ten minutes. Charles kept his head, however, and made notes until it grew too cold for him to hold a pen. He slowly released the hydrogen and landed again in thirty-five minutes, only three miles from the original landing spot. "It was the first solo flight in history."

Back in Britain, George III expressed his interest in getting his country into ballooning. Banks was still unconvinced that the French achievements had any practical applications, but he was definitely intrigued. William Watson Jr. had seen one of the unmanned test flights before the Montgolfiers' first manned launch, and excitedly wrote to Herschel about it. Herschel immediately thought about the possibility of using balloons to carry telescopes high into the upper air. Others began to think of the sinister side of ballooning. The novelist Horace Walpole feared the conversion of balloons into "new engines of destruction to the human race."  Benjamin Franklin recognized the military potential of aircraft and calculated that five thousand balloons, each carrying two men, could result in an airborne invasion from France.

But by the summer of 1784, the balloon craze had spread to England. "Unmanned and then manned ascents took place in almost every large city in the kingdom -- London, Oxford, Cambridge, Bristol, Edinburgh." And a twenty-five-year-old Italian, Vincent Lunardi, began to capitalize on the British enthusiasm for balloons. He made his first ascent in London on September 15, 1784, with a crowd of 150,000 as witnesses. "Lunardi drifted north-westwards across London and into Hertfordshire, eating legs of chicken and drinking champagne, and occasionally trying to 'row' his balloon with a pair of aerial oars." But his balloon had no release valve, so he had to try to snag something on the ground with a grappling anchor to end his flight, which he did in a field just outside of Ware.

When he returned to London, "a curiously modern publicity machine began to roll. He sold exclusive rights to his story, and an in-depth interview, to the Morning Post." He was introduced to the king and given a watch by the Prince of Wales, souvenirs of his flight were marketed, and he became the toast of fashionable London. Banks, on the other hand, was unimpressed, and privately referred to Lunardi as "a charlatan." Samuel Johnson was also critical of the hype that surrounded Lunardi, even before the flight, pointing out that buying a ticket to the launch was foolish because "in less than a minute they who gaze at a mile's distance will see all that can be seen." He also expressed skepticism about Lunardi's claim that he would be able to steer the balloon with his oars -- and he was correct. As for ballooning in general, he pointed out that since it couldn't be steered effectively, a balloon failed to "serve any purpose of communication; and it can give no new intelligence of the state of the air at different heights, till they have ascended above the height of mountains, which they seem never likely to do."

Another sensation was caused by Lunardi in June 1785 when he proposed to take the actress Mrs. Sage, who was a rather large woman, and a young man named George Biggin aloft with him. Mrs. Sage was to be the "First Aerial female." But the weight of the three passengers and the elaborate and showy trappings that had been attached to the gondola proved too much for the balloon, so Lunardi jumped out, leaving the two passengers to conduct the flight themselves.

Unfortunately, in his haste to depart, Lunardi failed to do up the lacings of the gondola's door. As the balloon sailed away over Piccadilly, the crowd were treated to the provoking sight of the beautiful Mrs Sage on all fours in the open entrance of the gondola. The crowd assumed that she had fainted, and was perhaps receiving some kind of intimate first-aid from Mr Biggin. 

After Mrs. Sage's flight, cartoonists indulged in ribald speculation

In fact, Mrs. Sage was trying to lace up the door, but when she regained her feet, she stepped on the barometer and broke it, so there was no way to measure how high they flew. So they drifted on, eating cold chicken and drinking Italian sparkling wine, until they landed in a field near Harrow, where they were threatened by an angry farmer and had to be rescued from him by the schoolboys from Harrow School. Afterward, there was ribald speculation about what may have happened between Biggin and Mrs. Sage during the flight. "Gallantly, Mr Biggin refused to comment."

The lack of scientific value of Lunardi's flights became the subject of criticism, and his reputation suffered in 1785 when a young man, Ralph Heron, became entangled in the ropes during a launch at Newcastle, was carried a hundred feet into the air, and fell to his death.

4. The Age of Wonder, by Richard Holmes, pp. 76-113

Herschel on the Moon, 5-7

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In 1766 Herschel moved to Bath, where he was not only organist in the Octagon
Chapel but also played in the orchestra in the Pump Room. He got into an argument with the impresario of the orchestra, James Linley, over orchestral arrangements, and set up a rival orchestra for a season, but finally made up with Linley and combined forces with him. When Linley decided to move to London, Herschel became the sole director of the concerts. He also composed and gave music lessons.

In February 1766 he had begun his first Astronomical Observation Journal, while also reading books on astronomy and attending lectures by the astronomer James Ferguson in the Pump Room. He began collecting telescopes and studying their construction. He found that refractor telescopes -- the straight kind with lenses at each end of the tube -- were insufficient for observing the stars, and turned his attention toward the reflector telescope invented by Newton. The concave mirrors in reflector telescopes gather and concentrate more light and produce less distortion than refractors.

Before Herschel, astronomers treated the night sky as if it were "the interior surface of a decorated dome, inlaid with constellations.... 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." But the kind of mirror he would need for a reflector telescope capable of the exploration Herschel envisioned was too expensive. So he decided he would make them himself, out of metal, not glass.

Herschel's brothers, Jacob, Dietrich, and Alexander, came to visit him in Bath, and in 1770 Alexander came to stay with William in a house he rented at 7 New King Street where he gave music and singing lessons. William was concerned about Caroline, who was now twenty-one, but her mother was reluctant to give up her free housemaid until he went to Hanover and promised to pay her for a maid to replace Caroline. She returned to England with him in August 1772. He began to give her lessons in English as well as singing and the harpsichord.

As in Hanover, Caroline found herself playing housekeeper, but with the addition of music lessons, English lessons, reading aloud from English novels, and talking about astronomy. "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 ... was bursting with unfulfilled dreams and longings."

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. 

Herschel began work on the mirrors for his telescope, getting the tools he needed for grinding and polishing the metal from John Michel, a fellow astronomer in Bath who, like Herschel, had some unconventional ideas, "such as the existence of 'black holes' in space from which light itself could not escape."

The moulds for casting metal mirrors were formed from horse-dung, and after the molten metal was poured and cooled it had to be ground down into a concave shape. It then had to be polished continually for hours without stopping; otherwise the metal would harden and become useless. In addition, there was the danger that the furnace might explode. The house at 7 New King Street became "a pungent, chaotic workshop." Caroline would read aloud to William while he polished the mirrors: "Don Quixote, the Arabian Nights, Sterne's Tristram Shandy -- all tales of fantastic adventures or eccentric heroes." Sometimes she even had to feed him by hand while he worked as long as sixteen hours without a break.

A Victorian illustrator portrayed the collaboration of William and Caroline Herschel as "a comfortable domestic scene ... in an elegant drawing room.... In fact these epic polishing sessions took place [in] the unheated, stone-flagged basement [where they] were surrounded by tools and chemicals, and the distinct, pungent smell of the horse-dung moulds. It was dirty, monotonous and exhausting work."

Herschel's first five-foot reflector telescope, finished in 1774, had a six-inch diameter mirror and was mounted in "a beautiful octagonal case of gleaming mahogany." He used it to study the moon and the then-mysterious nebulae. "Even at this early stage Herschel has the notion of a changing universe, and that nebulae might hold some clue to this mystery." When he began studying nebulae, just under a hundred had been cataloged by the French astronomer Charles Messier. "Within a decade, by the mid-1780s, Herschel would have increased this tenfold, to over a thousand nebulae.... Herschel suspected that they were star clusters at immense distances, whose composition might hold a clue to an entirely new kind of universe."

Meanwhile, to assuage the uneasiness of Jacob and Anna about Caroline's living in England, he reported that she had a small millinery business that she was running successfully, as well as continuing her music lessons. She had begun to perform as a singer in his concerts at the Pump Room. In 1779, Jacob cut back on the number of music students he was teaching, and began to work on a project to compile a catalog of double stars. He had already discovered that the Pole Star, "the key to navigation, and the poet's traditional emblem of steadiness and singularity, for centuries," was in fact two stars. By facilitating the measurement of parallax, double stars, he thought, "might provide a method of gauging the earth's distance from the rest of the Milky Way."

Conventional ideas about the cosmos at the time was not only that it was only a few thousand years old, but that the universe was only a few million miles in extent. The "fixed stars" were thought to be in an unchanging pattern and their brightness to be "a function of their size, rather than their distance.... One of Herschel's most simple and radical ideas was to assume exactly the opposite." But people had begun to speculate that the universe was much larger and that there was a high probability of extraterrestrial life.

The interest in extraterrestrial life underlay Herschel's fascination with the moon, which he was studying when, in December 1779, William Watson Jr. came upon him looking through his telescope."This was Herschel's first really important scientific contact in England, one not made until he was forty-one. Watson was only thirty-three." They became friends quickly, and Caroline later recalled that Watson came home with Herschel that night and talked until the next morning. Watson arranged Herschel's election to the Bath Philosophical Society as "optical instrument maker and mathematician," and helped him with his mirror-making. He encouraged Herschel to submit thirty-one papers to the society. Some of them were so speculative that they would now be considered "thought experiments." Among the more outlandish of them featured Herschel's idea that the craters on the moon might be man-made and designed to provide solar power to the cities and towns contained within them.

In 1781, Caroline closed her millinery shop, but it took her some time to sell off the stock, so that she was away from the house at 19 New King Street when William made a momentous discovery. On March 13 he observed "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." In a footnote, Holmes makes this observation:

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.

But the sighting of the "disc-like object" was hardly a "Eureka moment." Herschel thought he had found a new comet, and the record in his observation book contains "no expression of excitement or anticipation." Gradually, however, he began to devote his attention to the object, first to prove that it was definitely in motion and therefore not a fixed star, and then to figure out whether it was really a comet, since comets typically had "a slightly blurred, fiery outline and a distinct tail or 'coma.'" This object had neither.

Even by April 6, he was still calling it a comet in his observation book, though "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)." When he finally decided it was a planet, he called it "Georgium Sidus" ("George's Star") after George III. It did not finally receive the name Uranus until the middle of the nineteenth century.

Herschel told William Watson about his "comet" on March 22, and Watson passed the word on to Nevil Maskelyne and Joseph Banks. Maskelyne still thought that Herschel was something of a crackpot, but he checked it out and reported to Watson that he thought it was a comet or a planet.

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.... King George III was particularly fascinated by stars, and particularly keen to outdo the French.

Finally, Maskelyne wrote directly to Herschel on April 23, and called it a planet in his letter. Herschel responded with a paper called "An Account of a Comet" in which he outlined the process of his discovery, and made it clear that he, too, thought it must be a planet, though he didn't actually say so -- probably under Watson's advice.

In his report to Banks, Maskelyne referred to Herschel as "the musician of Bath" and as "lucky" for having "accidentally" discovered the planet. "This suggestion that the discovery had been 'accidental,' and that he had been 'lucky,' was to grow increasingly disturbing to Herschel," who knew that his patient and meticulous survey and careful measuring and recording had enabled him to identify the planet. Fortunately, the rivalry with the French played in Herschel's favor when Charles Messier wrote to congratulate him on his discovery and give "his opinion that this was very likely to be the seventh planet in the solar system.... As Maskelyne and Banks were only too aware, Messier's congratulations would soon carry the weight of the entire French Académie des Sciences." And astronomers in Germany, Italy , Sweden and Russia joined in confirming and praising Herschel's discovery.

In May, Watson took Herschel to London to meet his father and Maskelyne, and Banks "claimed it as a decisive British victory over French astronomy," and announced that Herschel was to be elected to the Royal Society and receive the Copley Gold Medal -- though it took another six months for the bureaucracy to process both honors. Banks also urged Herschel to name the planet "or our nimble neighbours, the French, will certainly save us the trouble of Baptizing it." It was then that Herschel proposed naming it after the king.

Herschel was, however, still irritated by the "continuing murmurs in some quarters of the Royal Society that his discovery had been in some sense 'accidental.'" He reiterated his contention that it was the result of "a regular review of the sky" in letters to European astronomers, and as late as 1809 he was insisting that it was no accident. But he also began to romanticize the discovery, claiming that it took place in a single night instead of being the result of "the critical nights of measuring between 21 March and 6 April 1781. The effect of this account was to present and engagingly romantic image of science at work; the solitary man of genius pursuing the mysterious moment of revelation."

The discovery sparked a new popular enthusiasm for astronomy, reflected by the bestseller of 1786, Introduction to Astronomy in Letters to His Pupil by John Bonnycastle, who pointed out the challenge that astronomers were making to the biblical chronology of the creation, and wrote:

"Astronomy has enlarged the sphere of our conceptions, and opened to us a 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." 

Though the discovery of Uranus "became a symbol of the new, pioneering discoveries of Romantic science," and was even celebrated in verse by Erasmus Darwin in his poem The Botanic Garden, there were still skeptics about Herschel and his telescopes. So Herschel packed up his telescope and brought it to Greenwich, where Maskelyne was duly impressed by the quality and clarity of Herschel's mirrors and acknowledged that "they were far more powerful than any of the official observatory telescopes, and probably than any other telescope in Europe."

In May 1782 Herschel was presented to the king and appointed the King's Personal Astronomer at Windsor with a salary of £200 per year. William, Caroline and Alexander moved to Datchet, a village near Windsor, in July 1782. He brought his telescope to Windsor for a demonstration to the royal family. The teenage princesses, Charlotte, Augusta and Elizabeth, were particularly impressed by the astronomer, especially after, on a cloudy night, he rigged up cardboard models of Jupiter and Saturn, illuminated them with candles, and placed them on a distant wall, then focused down the seven-foot telescope so they could view them.

Stargazing became a pastime that especially impressed the young Coleridge, who never forgot that when he was eight, he was taken out into the fields by his father to look at the night sky. "His Romantic sensibility -- even at the age of eight -- already inhabited the infinite and the inexplicable." Keats remembered a time at school when "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) ... a gloriously chaotic 'human orrery.'" Keats was awarded Bonnycastle's Introduction to Astronomy as a 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.'"