HERSCHEL AS PROFESSIONAL ASTRONOMER.
On 1st August, 1782, William and Caroline Herschel, in accordance with the obligation of the holder of the new office of King's Astronomer to reside near Windsor, entered into occupation of a large house on Datchet Common. The house was in a ruinous condition and the garden and grounds were overgrown with weeds. Nevertheless there were, in Herschel's eyes, compensating advantages. There were outhouses available for the work of telescope-making; a large laundry capable of refitting as a library; and, most important of all, a grass lawn where telescopes could be erected. Despite the discomforts of the half-ruinous house, and the separation from congenial friendships—most of all from Alexander Herschel, who remained in Bath to continue his musical career—William Herschel was in the best of health and spirits. "Much of my brother's time," Caroline Herschel records, "was taken up in going when the evenings were clear to the Queen's Lodge to show the King, etc., objects through the seven-foot". Undoubtedly there was much exacting and irksome duty of this kind, of which Caroline complains in her reminiscences again and again. Yet despite this, and despite also the smallness of his salary, Herschel always expressed gratitude for the King's generosity. The personal relations between George III and his astronomer seem to have been consistently congenial; and one cannot help feeling that something more than expediency prompted Herschel in his choice of a name for the new planet which he had discovered.
As early as May, 1782—before the King had appointed him as King's Astronomer Herschel was apparently of opinion that the new planet should be named after George III. In a letter to Herschel, dated 10th May, 1782, Colonel Walsh, evidently one in close touch with the court, wrote: "In a conversation which I had the honour to hold with His Majesty on 30th ult. concerning you and your memorable discovery of a new planet, I took occasion to mention that you had a two-fold claim as a native of Hanover and a resident of Great Britain, where the discovery was made, to be permitted to name the planet from His Majesty". In a letter to his friend Watson in July, Herschel suggested the name, "Sidus Georginum". It was not until the following year, after he was settled at Datchet, that Herschel addressed to Sir Joseph Banks, President of the Royal Society, a letter concerning the name of the new planet. "In the fabulous ages of ancient times," he said in the course of this letter, "the appellations of Mercury, Venus, Mars, Jupiter, and Saturn were given to the planets as being the names of their principal heroes and divinities. In the present more philosophical era, it would hardly be allowable to have recourse to the same method and to call on Juno, Pallas, Apollo or Minerva for a name to our new heavenly body. The first consideration in any particular event or remarkable incident seems to be its chronology: if, in any future age, it should be asked when this last-found planet was discovered, it would be a very satisfactory answer to say, 'In the reign of King George the Third'. As a philosopher, then, the name of Georgium Sidus presents itself to me as an appellation which will conveniently convey the information of the time and country where and when it was brought to view." Herschel then proceeds to eulogise the King as "the liberal protector of every art and science," and as his own benefactor, and closes with these words: "By addressing this letter to you, Sir, as President of the Royal Society, I take the most effectual method of communicating that name to the Literati of Europe, which I hope they will receive with pleasure".
Herschel's suggestion, however, did not meet with the approval of the scientific world. As the late Sir Robert Ball happily expressed it, the continental astronomers thought that the King of England would "seem oddly associated with Jupiter and Saturn; perhaps also they considered that the British dominions, on which the Sun never sets, were already quite large enough without further extension to the celestial regions". Lalande proposed the name of Herschel, and for a considerable time the planet was thus known in France. Indeed the name was also adopted in many circles in Great Britain. Bode of Berlin, the editor of the "Astronomisches Jahrbuch" of the day and one of the leading German astronomers, suggested "Uranus," in keeping with the old custom of affixing mythological names to the celestial bodies. For years all three names were in use. In the "Nautical Almanac" the name, "the Georgian," evidently preferred to "Georgium Sidus," was used officially until 1847. By the middle of the century, however, the name "Uranus" had been generally adopted, and there can be no doubt that the decision was sound. Bode was right and Herschel wrong.
We can hardly suppress a feeling of regret that Herschel, with his great mind and soul, could have made a suggestion which savoured of sycophancy: but we must bear in mind the circumstances. No planetary discoveries had been made since prehistoric times, and there was something to be said for making a new departure. That Herschel's suggestion was not made solely out of gratitude is obvious from the fact that he had practically decided on the name before he was appointed to the new office. As a matter of fact, Herschel seems to have undoubtedly had for the King a high personal regard. They were both Hanoverians, and thus there was a sentimental tie between them: and George III., whatever condemnation we may pass on him as a monarch, seems undoubtedly to have taken an intelligent interest in astronomy. In his early days he had made observations at the private observatory at Kew. That he did take an intelligent interest is obvious from a letter which Herschel wrote on 20th May, 1787, to an official at Windsor Castle, in which he requested him to inform the King of the luminosity of a lunar crater, adding that he would himself be at Windsor in the evening to see the King's 10-foot telescope set up for observation.
Despite Herschel's own friendship for the King and his own silence as to the smallness of his salary, there can be no doubt that he was at first sorely handicapped by straitened circumstances. He had made a great financial sacrifice in accepting the post of King's Astronomer. Had he been able to avoid incurring expenses, he could have managed to live on £200 a year; but it was imperative for him to construct larger instruments, and the instruments which he had were in constant need of repair and readjustment. His salary, as has been well said by the late Miss Clerke, "gave him the means of living, but not of observing as he proposed to observe". Accordingly he plunged with enthusiasm into the work of making telescopes for sale. "The goodness of my telescopes," he wrote in his journal, "being already known, I was desired by the King to get some made for those who wished to have them. . . . This business in the end not only proved very lucrative, but also enabled me to make extensive experiments for polishing mirrors by machinery."
Despite the strenuous work of telescope-making, Herschel, while at Datchet, continued his nightly surveys of the sky. His third review of the heavens, which had been commenced at Bath, was completed in January, 1784. This review included all the stars of Flamsteed's catalogue and the small stars near them. The work was carried through with amazing rapidity. He would observe for ten or twelve hours at a stretch, and as many as 400 stars were observed and measured in the course of a night. Later in the same year, his attention was drawn to star-clusters and nebulae by the appearance of Messier's famous catalogue, and accordingly on 28th October, 1783, he began to "sweep the heavens" for these objects with his new 20-foot reflector of 18.7 inches aperture, and at the same time to "gauge" the depth of the sidereal system. A number of experimental observations were made, and on 18th December he commenced his systematic "sweeps," which were continued till 1802.
In this work he found his sister an invaluable helper. In 1782, she tells us, her thoughts were "anything but cheerful". "I found I was to be trained as an assistant-astronomer, and by way of encouragement, a telescope adapted for 'sweeping,' consisting of a tube with two glasses, such as are commonly used in a 'finder' was given me. I was to 'sweep for comets'. . . . But it was not until 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. . . . 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, of which I intended to give a catalogue; but at the end of 1783 I had only marked fourteen, when my sweeping was interrupted by being employed to write down my brother's observations with the large 20-foot." Caroline's observations are preserved in three volumes of quarto and four of folio. These observations were at first not unattended by danger. They were commenced when the mountings of the telescopes were in a very unfinished state, and Herschel was "elevated fifteen feet or more on a temporary cross-beam instead of a safe gallery". Caroline Herschel herself met with a somewhat severe accident on the last day of 1783, and she left it on record that the Italian astronomer Piazzi—discoverer of the first asteroid—"did not go home without getting broken shins by falling over the rack-bar".
By the summer of 1785, Herschel decided that the old house at Datchet was impossible as a permanent residence. An attack of ague was found to be due to its damp situation. Accordingly, early in June, the Herschels removed to a house at Clay Hall, near Old Windsor, where observations were at once commenced. But trouble arose with the landlady—"a litigious woman who refused to be bound to reasonable terms"—and in the following spring Herschel fixed upon a new home at Slough, near Windsor. Thither his instruments and apparatus were transported on 3rd April, 1786, without the loss of a single hour's observation. "The last night at Clay Hall," says Caroline, "was spent in sweeping till daylight and by the next evening the telescope stood ready for observation at Slough." This was the last removal. The remainder of Herschel's life was spent at Slough—"the spot of all the world," said Arago, "where the greatest number of discoveries have been made". Here for many years, Herschel and his devoted sister worked from twilight to dawn, sweeping for clusters and nebulae, counting the stars in limited regions of the heavens, occasionally scrutinising the Moon and the planets. "If it had not been," writes Caroline, "for the intervention of a cloudy or moonlit night, I know not when he or I either would have got any sleep." In the daytime, too, his activity was ceaseless. He had to attend to his telescopes and to direct the army of workmen who were constantly employed making repairs; in addition, he was actively employed systematising his observations and coordinating his results, which appeared in the long series of papers contributed to the "Philosophical Transactions" of the Royal Society—collected and published in two volumes in 1912.
It soon became apparent that the work of making telescopes for other observers, though lucrative, was in many respects a waste of time. Herschel had long contemplated the construction of a very large telescope, but this was impossible so long as his spare time was given to the manufacture of smaller instruments, the great majority of which passed into the possession of royal or aristocratic dabblers in astronomy and were practically mere ornaments. A few, however, were supplied to continental astronomers. With a 7-foot, Schröter, the German astronomer, practically inaugurated the systematic study of the Moon's surface.
Caroline Herschel notes that it was her brother's chief object at this time to construct a 30 or 40-foot instrument, "for he was then on the wrong side of forty-five and felt how great an injustice he would be doing to himself and to the cause of astronomy by giving up his time to making telescopes for other observers". But nothing could be done without a grant from the King; Herschel could not bear the expense of constructing a great telescope for himself. After some preliminary spade-work had been done in the proper quarters by his life-long friend, Sir William Watson, Herschel requested Sir Joseph Banks, President of the Royal Society, to make application for a grant from the King. In September, 1785, a grant of £2000 was made, and preparations for the making of the instrument were at once begun. Two years later a second sum of £2000 was granted, and in addition Herschel received, over and above his salary, £200 per annum for the up-keep of the telescope; while a salary of £50 a year was bestowed on Caroline Herschel as her brother's assistant. By this time her name was becoming famous in the world of science. On 1st August, 1786, during Herschel's absence in Germany, she discovered a comet, the first of eight similar objects to her credit. The small annuity conferred upon her was a recognition—painfully inadequate—of her own work in astronomical science.
The construction of the great telescope occupied nearly four years. The erection of this immense instrument took up a great deal of Herschel's attention. His sister asserted that "there is not one screwbolt about the whole apparatus but what was fixed under the immediate eye of my brother. I have seen him lie stretched many an hour in a burning sun, across the top beam while the iron-work for the various motions was being fixed. At one time, no fewer than twenty-four men (twelve and twelve relieving each other) kept polishing day and night; my brother, of course, never leaving them all the while, taking his food without allowing himself time to sit down to table."
This ceaseless industry bore fruit when in August, 1789, the great telescope was ready for use. Herschel's former telescopes had been Newtonians, with small secondary mirrors. In January, 1787, however, he made a novel experiment with his 20-foot telescope. In order to save the light lost by the second reflection, Herschel removed the small mirror and slightly tilted the tube. The result more than justified expectations, and the experiment resulted in the discovery of two satellites of Uranus. Accordingly, he decided to make the 40-foot telescope on this "front-view" principle. This particular form of the reflector is known as the Herschelian.
Herschel was very proud of his large telescope and in 1795 sent a description of it to the Royal Society. Yet, on the whole, its performances were disappointing. Immediately it was erected Herschel succeeded in confirming the existence of two new satellites of Saturn: and to the ringed planet he turned his great instrument on numerous occasions. But it was cumbersome and difficult to manipulate, and the speculum on which so much care had been bestowed preserved its original polish for no more than two years. In Herschel's later years, he rarely made use of it, although it remained standing until seventeen years after its maker's death. In 1839, it was dismantled by Sir John Herschel, and laid in a horizontal position, which it occupied for many years, until a falling tree destroyed all but ten feet of the tube.
The completion of the 40-foot was the climax of Herschel's career as a maker of telescopes. The fame of the great instrument spread over the world. Princes, dukes, and courtiers visited Slough in order to view one of the wonders of the age. Astronomers, too, came from all parts of the world—Lalande, Méchain, Legendre, Cassini from Paris, Oriani from Milan, Piazzi from Palermo, Sniadecki from Cracow. Slough became a place of pilgrimage, not only for astronomers, but also for large numbers who had only a slight interest in, or curiosity about, the science. Herschel did not abandon telescope-making altogether but it was not now so necessary for pecuniary reasons. On 8th May, 1788, Herschel was married to Mrs. Pitt, widow of John Pitt, Esq., and daughter of Mr. Adee Baldwin, a London merchant. Miss Burney, the novelist, has left on record her meeting with Herschel and his wife soon after the marriage. "His newly-married wife was with him, and his sister. His wife seems good-natured; she was rich, too! And astronomers are as able as other men to discern that gold can glitter as well as stars." Whether or not there is any ground for this hint as to a motive for Herschel's marriage, there can be no doubt that he was now relieved from all financial care. There can be no doubt either that the marriage was a very happy one, and that the relations between his wife and his sister were all that could be desired. From this time onwards, however, Caroline Herschel resided in lodgings in the village of Slough.
In the earlier part of his career, Herschel rarely went from home except on business. On 3rd July, 1786, accompanied by his brother Alexander, he started for Göttingen, in order to convey to the University one of his 10-foot reflectors as a gift from George III. This was his last visit to his native country. In 1792, he made an extensive tour in England and Scotland, in the company of a Polish friend, General Komarzewski. Visits were paid to the principal factories in the middle and north of England, and Herschel seems to have taken a 7-foot telescope with him in order to treat his hosts to views of the heavens. The tour embraced Coventry, Birmingham—where he dined with James Watt—Bangor, Carnarvon, and Manchester, then via Liverpool, Preston and Carlisle to Glasgow. Here he received the freedom of the city and the degree of LL.D. from the University. From Glasgow the friends proceeded to Edinburgh, from whose University Herschel had received the same degree six years earlier. In Edinburgh he met numerous literary and scientific men, including Principal Robertson and Dr. Hutton, and, in addition, inspected the Observatory. The return journey was made by Sunderland, Durham and Richmond in Yorkshire.
At the close of the eighteenth century, Herschel was at the zenith of his powers and at the height of his prosperity. Honorary degrees were conferred upon him and learned societies enrolled his name among their members. He accepted these recognitions of his genius, but put little stress upon them. Miss Burney, who along with her father visited him on numerous occasions, described Herschel as "perfectly unassuming, yet openly happy, and happy in the success of those studies which would render a mind less excellently formed presumptuous and arrogant. The King has not a happier subject than this man. . . . He seems a man without a wish that has its object in the terrestrial globe."