Sir William Herschel: His Life and Works Part 4

TO MISS HERSCHEL.

"_July 3, 1782._"

"DEAR CAROLINA:--

"I have been so much employed that you will not wonder at my not writing sooner. The letter you sent me last Monday came very safe to me. As Dr. WATSON has been so good as to acquaint you and ALEXANDER with my situation, I was still more easy in my silence to you. Last night the King, the Queen, the Prince of Wales, the Princess Royal, Princess SOPHIA, Princess AUGUSTA, etc., Duke of MONTAGUE, Dr.

HEBERDEN, M. DE LUC, etc., etc., saw my telescope, and it was a very fine evening. My instrument gave general satisfaction. The king has very good eyes, and enjoys observations with telescopes exceedingly.

"This evening, as the king and queen are gone to Kew, the princesses were desirous of seeing my telescope, but wanted to know if it was possible to see without going out on the gra.s.s, and were much pleased when they heard that my telescope could be carried into any place they liked best to have it. About eight o'clock it was moved into the queen's apartments, and we waited some time in hopes of seeing _Jupiter_ or _Saturn_. Meanwhile I showed the princesses, and several other ladies who were present, the speculum, the micrometers, the movements of the telescopes, and other things that seemed to excite their curiosity. When the evening appeared to be totally unpromising, I proposed an artificial _Saturn_ as an object, since we could not have the real one. I had beforehand prepared this little piece, as I guessed by the appearance of the weather in the afternoon we should have no stars to look at. This being accepted with great pleasure, I had the lamps lighted up which illuminated the picture of a _Saturn_ (cut out in pasteboard) at the bottom of the garden wall. The effect was fine, and so natural that the best astronomer might have been deceived. Their royal highnesses and other ladies seemed to be much pleased with the artifice.

"I remained in the queen's apartment with the ladies till about half after ten; when in conversation with them I found them extremely well instructed in every subject that was introduced, and they seemed to be most amiable characters. To-morrow evening they hope to have better luck, and nothing will give me greater happiness than to be able to show them some of those beautiful objects with which the heavens are so gloriously ornamented."

CAROLINA'S diary goes on:

"Sir WILLIAM WATSON returned to Bath after a fort-night or three weeks' stay. From him we heard that my brother was invited to Greenwich with the telescope, where he was met by a numerous party of astronomical and learned gentlemen, and trials of his instrument were made. In these letters he complained of being obliged to lead an idle life, having nothing to do but to pa.s.s between London and Greenwich. Sir WILLIAM received many letters, which he was so kind as to communicate to us. By these, and from those to ALEXANDER or to me, we learned that the king wished to see the telescope at Windsor.

At last a letter, dated July 2, arrived from THERESE, and from this and several succeeding ones we gathered that the king would not suffer my brother to return to his profession again, and by his writing several times for a supply of money we could only suppose that he himself was in uncertainty about the time of his return.

"In the last week of July my brother came home, and immediately prepared for removing to Datchet, where he had taken a house with a garden and gra.s.s-plat annexed, quite suitable for the purpose of an observing-place. Sir WILLIAM WATSON spent nearly the whole time at our house, and he was not the only friend who truly grieved at my brother's going from Bath; or feared his having perhaps agreed to no very advantageous offers; their fears were, in fact, not without reason. . . . The prospect of entering again on the toils of teaching, etc., which awaited my brother at home (the months of leisure being now almost gone by), appeared to him an intolerable waste of time, and by way of alternative he chose to be royal astronomer, with a salary of 200 a year. Sir WILLIAM WATSON was the only one to whom the sum was mentioned, and he exclaimed, 'Never bought monarch honor so cheap!' To every other inquirer, my brother's answer was that the king had provided for him."

On the 1st of August, 1782, the family removed to Datchet. The last musical duty was performed on Whit-Sunday, 1782, in St. Margaret's Chapel, Bath, when the anthem for the day was of HERSCHEL'S own composition.

The end of the introductory epoch of his life is reached. Henceforth he lived in his observatory, and from his forty-fourth year onwards he only left it for short periods to go to London to submit his cla.s.sic memoirs to the Royal Society. Even for these occasions he chose periods of moonlight, when no observations could be made.

He was a private man no longer. Henceforth he belongs to the whole world.

FOOTNOTES:

[10] Probably on the model of one of SHORT'S Gregorian telescopes, which were then the best instruments of the kind.

[11] For a description of the main points of HERSCHEL'S processes of making reflectors, which will ill.u.s.trate his strong mechanical talents, see _Encyclopaedia Britannica_, eighth edition, article _Telescope_.

[12] These have never been published, nor is it likely at this day, when our measuring instruments are so greatly improved, that they would be of any material value to science, although of interest as giving the proofs of HERSCHEL'S a.s.siduity and skill. He was always more than the maker of telescopes, for he was never content until they were applied to the problems of astronomy.

[13] ARAGO has implied that if HERSCHEL had directed his telescope to _Ura.n.u.s_ only eleven days earlier than he did, this discovery would have escaped him, since at that time (March 2, 1781) the planet was at its _station_, and had no motion relative to the star.

This is an entire misconception, since the new planet was detected by its physical appearance, and not by its motion. Does any one suppose that "a new and singular star" like this would have been once viewed and then forgotten?

[14] Four of _Jupiter_, one of the earth, and one of _Saturn_.

[15] JOHN MICh.e.l.l had been a member of the Royal Society since 1760: he died in 1793. He was a philosophical thinker, as is shown by his memoirs on the distances of the stars, and by his invention of the method for determining the earth's density. It is not certain that he was personally known to HERSCHEL, although his writings were familiar to the latter.

ALEXANDER WILSON was Professor of Astronomy at Glasgow, and is chiefly known to us by his theory of the nature of the solar spots, which was adopted and enlarged by HERSCHEL. He died in 1786; but the families of WILSON and HERSCHEL remained close friends.

[16] _Berliner Jahrbuch_, 1784, p. 211. In the _Connaissance des Tems_ for 1784 he is called "HOROCh.e.l.lE."

[17] At the presentation Sir JOSEPH BANKS, the President of the Royal Society, said: "In the name of the Royal Society I present to you this gold medal, the reward which they have a.s.signed to your successful labors, and I exhort you to continue diligently to cultivate those fields of science which have produced to you a harvest of so much honor.

Your attention to the improvement of telescopes has already amply repaid the labor which you have bestowed upon them; but the treasures of the heavens are well known to be inexhaustible. Who can say but your new star, which exceeds _Saturn_ in its distance from the sun, may exceed him as much in magnificence of attendance? Who knows what new rings, new satellites, or what other nameless and numberless phenomena remain behind, waiting to reward future industry and improvement?"

CHAPTER III.

LIFE AT DATCHET, CLAY HALL, AND SLOUGH; 1782-1822.

The new house at Datchet, which was occupied from 1782 till 1785, was a source of despair to CAROLINA HERSCHEL, who looked upon its desolate and isolated condition with a housekeeper's eyes. This was nothing to her brother, who gayly consented to live upon "eggs and bacon," now that he was free at last to mind the heavens. The ruinous state of the place had no terrors in his eyes, for was there not a laundry which would serve as a library, a large stable which was just the place for the grinding of mirrors, and a gra.s.s-plat for the small twenty-foot reflector?

Here they set to work at astronomy; the brother with the twenty-foot, the sister aiding him, and at odd times sweeping for comets. In the course of her life she discovered no less than eight, and five of these were first seen by her.

In 1787 HERSCHEL wrote his paper "On three Volcanoes in the Moon,"

which he had observed in April of that year. In this he mentions previous observations of the same sort. I do not remember that the following account of these has ever been put on record in English.

Baron VON ZACH writes from London to BODE:[18]

"Probably you have heard also of the volcanoes in the moon, which HERSCHEL has observed. . . . I will give you an account of it as I heard it from his own lips. Dr. LIND, a worthy physician in Windsor, who has made himself known through his two journeys in China, and who is a friend of our HERSCHEL'S, was with his wife one evening on a visit to HERSCHEL in Datchet [1783, May 4]. On this evening there was to be an occultation of a star at the moon's dark limb. This was observed by HERSCHEL and Doctor LIND. Mrs. LIND wished also to see what was occurring, and placed herself at a telescope and watched attentively.

"Scarcely had the star disappeared before Mrs. LIND thought she saw it again, and exclaimed that the star had gone in front of, and not behind the moon. This provoked a short astronomical lecture on the question, but still she would not credit it, because she _saw_ differently. Finally HERSCHEL stepped to the telescope, and in fact he saw a bright point on the dark disc of the moon, which he followed attentively. It gradually became fainter and finally vanished.". . .

The life at Datchet was not free from its annoyances.

"Much of my brother's time 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. But when the days began to shorten, this was found impossible, for the telescope was often (at no small expense and risk of damage) obliged to be transported in the dark back to Datchet, for the purpose of spending the rest of the night with observations on double stars for a second catalogue. My brother was, besides, obliged to be absent for a week or ten days, for the purpose of bringing home the metal of the cracked thirty-foot mirror, and the remaining materials from his work-room. Before the furnace was taken down at Bath, a second twenty-foot mirror, twelve inches diameter, was cast, which happened to be very fortunate, for on the 1st of January, 1783, a very fine one cracked by frost in the tube.

. . . "In my brother's absence from home I was, of course, left alone to amuse myself with my own thoughts, which were anything but cheerful. I found I was to be trained for an a.s.sistant astronomer, and, by way of encouragement, a telescope adapted for 'sweeping,'

consisting of a tube with two gla.s.ses, such as are commonly used in a 'finder,' was given me. I was 'to sweep for comets,' and I see, by my journal, that I began August 22d, 1782, to write down and describe all remarkable appearances 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 gra.s.s-plot covered with dew or h.o.a.r-frost, without a human being near enough to be within call. I knew too little of the real heavens to be able to point out every object so as to find it again, without losing much time by consulting the Atlas. But 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 when I could have his a.s.sistance immediately if I found a nebula or cl.u.s.ter 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 twenty-foot.

I had, however, the comfort to see that my brother was satisfied with my endeavors to a.s.sist him when he wanted another person either to run to the clocks, write down a memorandum, fetch and carry instruments, or measure the ground with poles, etc., etc., of which something of the kind every moment would occur. For the a.s.siduity with which the measurements on the diameter of the _Georgium Sidus_, and observations of other planets, double stars, etc., etc., were made, was incredible, as may be seen by the various papers that were given to the Royal Society in 1783, which papers were written in the daytime, or when cloudy nights interfered. Besides this, the twelve-inch speculum was perfected before the spring, and many hours were spent at the turning-bench, as not a night clear enough for observing ever pa.s.sed but that some improvements were planned for perfecting the mounting and motions of the various instruments then in use, or some trials were made of new constructed eye-pieces, which were mostly executed by my brother's own hands. Wishing to save his time, he began to have some work of that kind done by a watchmaker who had retired from business and lived on Datchet Common; but the work was so bad, and the charges so unreasonable, that he could not be employed. It was not till some time afterwards, in his frequent visits to the meetings of the Royal Society (made in moonlight nights), that he had an opportunity of looking about for mathematical workmen, opticians, and founders. But the work seldom answered expectation, and it was kept, to be executed with improvements by ALEXANDER during the few months he spent with us.

"The summer months pa.s.sed in the most active preparation for getting the large twenty-foot ready against the next winter. The carpenters and smiths of Datchet were in daily requisition, and, as soon as patterns for tools and mirrors were ready, my brother went to town to have them cast, and, during the three or four months ALEXANDER could be absent from Bath, the mirrors and optical parts were nearly completed.

"But that the nights after a day of toil were not given to rest, may be seen by the observations on _Mars_, of which a paper, dated December 1, 1783, was given to the Royal Society. Some trouble, also, was often thrown away, during those nights, in the attempt to teach me to remeasure double stars with the same micrometers with which former measures had been taken, and the small twenty-foot was given me for that purpose. . . . I had also to ascertain their places by a transit instrument lent for that purpose by Mr. DALRYMPLE; but, after many fruitless attempts, it was seen that the instrument was, perhaps, as much in fault as my observations."

In 1783 HERSCHEL says:

"I have now finished my third review of the heavens. The first was made with a Newtonian telescope something less than seven feet focal length, a power of 222, and an aperture of four and a half inches.

It extended only to stars of the first, second, third, and fourth magnitudes. My second review was made with an instrument much superior to the other, of 85.2 inches focus, 6.2 inches aperture, and power 227. It extended to all the stars of HARRIS'S maps and the telescopic ones near them, as far as the eighth magnitude. The Catalogue of Double Stars and the discovery of the _Georgium Sidus_, were the results of that review. The third was with the same instrument and aperture, but with a power of 460. This review extended to all the stars of FLAMSTEED'S Catalogue, together with every small star about them, to the amount of a great many thousands of stars. I have, many a night, in the course of eleven or twelve hours of observation, carefully and singly examined not less than 400 celestial objects, besides taking measures, and sometimes viewing a particular star for half an hour together."

The fourth review began with the twenty-foot, in 1784.

"My brother began his series of sweeps when the instrument was yet in a very unfinished state, and my feelings were not very comfortable when every moment I was alarmed by a crack or fall, knowing him to be elevated fifteen feet or more on a temporary cross-beam, instead of a safe gallery. The ladders had not even their braces at the bottom; and one night, in a very high wind, he had hardly touched the ground before the whole apparatus came down.

Some laboring men were called up to help in extricating the mirror, which was, fortunately, uninjured, but much work was cut out for carpenters next day. I could give a pretty long list of accidents which were near proving fatal to my brother as well as myself. To make observations with such large machinery, where all around is in darkness, is not unattended with danger, especially when personal safety is the last thing with which the mind is occupied; even poor PIAZZI did not go home without getting broken shins by falling over the rack-bar.

"In the long days of the summer months many ten and seven foot mirrors were finished; there was nothing but grinding and polishing to be seen. For ten-foot, several had been cast with ribbed backs, by way of experiment, to reduce the weight in large mirrors. In my leisure hours I ground seven-foot and plain mirrors from rough to fining down, and was _indulged_ with polishing and the last finishing of a very beautiful mirror for Sir WILLIAM WATSON.

"An account of the discoveries made with the twenty-foot and the improvements of the mechanical parts of the instrument during the winter of 1785 is given with the catalogue of the first 1,000 new nebulae. By which account it must plainly appear that the expenses of these improvements, and those which were yet to be made in the apparatus of the twenty-foot (which, in fact, proved to be a model of a larger instrument), could not be supplied out of a salary of 200 a year, especially as my brother's finances had been too much reduced during the six months before he received his _first_ quarterly payment of _fifty pounds_ (which was Michaelmas, 1782).

Travelling from Bath to London, Greenwich, Windsor, backwards and forwards, transporting the telescope, etc., breaking up his establishment at Bath and forming a new one near the court, all this, even leaving such personal conveniences as he had for many years been used to, out of the question, could not be obtained for a trifle; a good large piece of ground was required for the use of the instruments, and a habitation in which he could receive and offer a bed to an astronomical friend, was necessary after a night's observation.

"It seemed to be supposed that enough had been done when my brother was enabled to leave his profession that he might have time to make and sell telescopes. The king ordered four ten-foot himself, and many seven-foot besides had been bespoke, and much time had already been expended on polishing the mirrors for the same. But all this was only r.e.t.a.r.ding the work of a thirty or forty foot instrument, which it was my brother's chief object to obtain as soon as possible; 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.

"Sir WILLIAM WATSON, who often in the lifetime of his father came to make some stay with us at Datchet, saw my brother's difficulties, and expressed great dissatisfaction. On his return to Bath he met, among the visitors there, several belonging to the court, to whom he gave his opinion concerning his friend and his situation very freely. In consequence of this, my brother had soon after, through Sir J. BANKS, the promise that 2,000 would be granted for enabling him to make himself an instrument.