I was present on one occasion at a popular lecture delivered in Greenwich, when the lecturer referred to the way in which so many English people travel to the ends of the earth in order to see interesting or wonderful places, and yet entirely neglect places of at least equal importance in their own land. 'Ten minutes' walk from this hall,' he said, 'is Greenwich Observatory, the most famous observatory in the world. Most of you see it every day of your lives, and yet I dare say that not one in a hundred of you has ever been inside.'
Whether the lecturer was justified in the general scope of his stricture or not, the particular instance he selected was certainly unfortunate. It was not the fault of the majority of his audience that they had not entered Greenwich Observatory, since the regulations by which it is governed forbade them doing so. These rules are none too stringent, for the efficiency of the institution would certainly suffer if it were made a 'show' place, like a picture gallery or museum. The work carried on therein is too continuous and important to allow of interruption by daily streams of sightseers.
To those who may at some time or other visit the Observatory it may be of interest to have at hand a short account of its history, principal instruments, and work. To the far greater number who will never be able to enter it, but who yet feel an interest in it, I would trust that this little book may prove some sort of a substitute for a personal visit.
I would wish to take this opportunity of thanking the Astronomer Royal for his kind permission to reproduce some of the astronomical photographs taken at the Observatory and to photograph the domes and instruments. I would also express my thanks to Miss Airy, for permission to reproduce the photograph of Sir G. B. Airy; to Mr. J. Nevil Maskelyne, F.R.A.S., for the portrait of Dr. Maskelyne; to Mr. Bowyer, for procuring the portraits of Bliss and Pond; to Messrs. Edney and Lacey, for many photographs of the Royal Observatory; and to the Editor of Engineering, for permission to copy two engravings of the Astrographic telescope.
E. W. M.
Royal Observatory, Greenwich,
August, 1900.
THE NEW BUILDING.
(From a photograph by Mr. Lacey.)
I had parted from a friend one day just as he met an acquaintance of his to whom I was unknown. 'Who is that?' said the newcomer, referring to me. My friend replied that I was an astronomer from Greenwich Observatory.
'Indeed; and what does he do there?'
This question completely exhausted my friend's information, for as his tastes did not lead him in the direction of astronomy, he had at no time ever concerned himself to inquire as to the nature of my official duties. 'Oh—er—why—he observes, don't you know?' and the answer, vague as it was, completely slaked the inquirer's thirst for knowledge.
It is not every one who has such exceedingly nebulous ideas of an astronomer's duties. More frequently we find that the inquirer has already formed a vivid and highly-coloured picture of the astronomer at his 'soul-entrancing work.' Resting on a comfortable couch, fixed at a luxurious angle, the eye-piece of some great and perfect instrument brought most conveniently to his eye, there passes before him, in grand procession, a sight such as the winter nights, when clear and frosty, give to the ordinary gazer, but increased ten thousand times in beauty, brilliance, and wonder by the power of his telescope. For him Jupiter reveals his wind-drifted clouds and sunset colours; for him Saturn spreads his rings; for him the snows of Mars fall and melt, and a thousand lunar plains are ramparted with titanic crags; his are the star-clusters, where suns in their first warm youth swarm thicker than hiving bees; his the faint veils of nebulous smoke, the first hint of shape in worlds about to be, or, perchance, the last relics of worlds for ever dead. And beside the enjoyment of all this entrancing spectacle of celestial beauty, the fortunate astronomer sits at his telescope and discovers—always he discovers.
This, or something like it, is a very popular conception of an astronomer's experiences and duty; and consequently many, when they are told that 'discoveries' are not made at Greenwich, are inclined to consider that the Observatory has failed in its purpose. An astronomer without 'discoveries' to his record is like an angler who casts all day and comes home without fish—obviously an idle or incompetent person.
Again, it is considered that astronomy is a most transcendental science. It deals with infinite distances, with numbers beyond all power of human intellect to appreciate, and therefore it is supposed, on the one hand, that it is a most elevating study, keeping the mind continually on the stretch of ecstasy, and, on the other hand, that it is utterly removed from all connection with practical, everyday, ordinary life.
These ideas as to the Royal Observatory, or ideas like them, are very widely current, and they are, in every respect, exactly and wholly wrong. First of all, Greenwich Observatory was originally founded, and has been maintained to the present day, for a strictly practical purpose. Next, instead of leading a life of dreamy ecstasy or transcendental speculation, the astronomer has, perhaps, more than any man, to give the keenest attention to minute practical details. His life, on the one side, approximates to that of the engineer; on the other, to that of the accountant. Thirdly, the professional astronomer has hardly anything to do with the show places of the sky. It is quite possible that there are many people whose sole opportunity of looking through a telescope is the penny peep through the instrument of some itinerant showman, who may have seen more of these than an active astronomer in a lifetime; while as to 'discoveries,' these lie no more within the scope of our national observatory than do geographical discoveries within that of the captain and officers of an ocean liner.
If it is not to afford the astronomer beautiful spectacles, nor to enable him to make thrilling discoveries, what is the purpose of Greenwich Observatory?
First and foremost, it is to assist navigation. The ease and certainty with which to-day thousands of miles of ocean are navigated have ceased to excite any wonder. We do not even think about it. We go down to the docks and see, it may be, one steamer bound for Halifax, another for New York, a third for Charleston, a fourth for the West Indies, a fifth for Rio de Janeiro; and we unhesitatingly go on board the one bound for our chosen destination, without the faintest misgiving as to its direction. We have no more doubt about the matter than we have in choosing our train at a railway station. Yet, whilst the train is obliged to follow a narrow track already laid for it, from which it cannot swerve an inch, the steamer goes forth to traverse for many days an ocean without a single fixed mark or indication of direction; and it is exposed, moreover, to the full force of winds and currents, which may turn it from its desired path.
But for this facility of navigation, Great Britain could never have obtained her present commercial position and world-wide empire.
Part of this facility is, of course, due to the invention of the steam engine, but much less than is generally supposed. Even yet the clippers, with their roods of white canvas, are not entirely superseded; and if we could conceive of all steamships being suddenly annihilated, ere long the sailing vessels would again, as of yore, prove the
But with the art of navigation thrust back into its condition of a hundred and fifty years ago, it is doubtful whether a sufficient tide of commerce could be carried on to keep our home population supplied, or to maintain a sufficiently close political connection between these islands and our colonies.
Navigation was in a most primitive condition even as late as the middle of last century. Then the method of finding a ship's longitude at sea was the insufficient one of dead reckoning. In other words, the direction and speed of the ship were estimated as closely as possible, and so the position was carried on from day to day. The uncertainty of the method was very great, and many terrible stories might be told of the disastrous consequences which might, and often did, follow in the train of this method by guess-work. It will be sufficient, however, to cite the instance of Commodore Anson. He wanted to make the island of Juan Fernandez, where he hoped to obtain fresh water and provisions, and to recruit his crew, many of whom were suffering from that scourge of old-time navigators—scurvy. He got into its latitude easily enough, and ran eastward, believing himself to be west of the island. He was, however, really east of it, and therefore made the mainland of America. He had therefore to turn round and sail westwards, losing many days, during which the scurvy increased upon his crew, many of whom died from the terrible disease before he reached the desired island.
The necessity for finding out a ship's place when at sea had not been very keenly felt until the end of the fifteenth century. It was always possible for the sailor to ascertain his latitude pretty closely, either by observing the height of the pole-star at night or the height of the sun at noonday; and so long as voyages were chiefly confined to the Mediterranean Sea, and the navigators were content for the most part to coast from point to point, rarely losing sight of land, the urgency of solving the second problem—the longitude of the ship—was not so keenly felt. But immediately the discoveries of the great Portuguese and Spanish navigators brought a wider, bolder navigation into vogue, it became a matter of the first necessity.
To take, for example, the immortal voyage of Christopher Columbus. His purpose in setting out into the west was to discover a new way to India. The Venetians and Genoese practically possessed the overland route across the Isthmus of Suez and down the Red Sea. Vasco da Gama had opened out the route eastward round the Cape. Firmly convinced that the world was a globe, Columbus saw that a third route was possible, namely, one nearly due west; and when, therefore, he reached the Bahamas, after traversing some 66° of longitude, he believed that he was in the islands of the China Sea, some 230° from Spain. Those who followed him still laboured under the same impression, and when they reached the mainland of America, believed that they were close to the shores of India, which was still distant from them by half the circumference of the globe.
Little by little the intrepid sailors of the sixteenth century forced their way to a true knowledge of the size of the globe, and of the relative position of the great continents. But this knowledge was only attained after many disasters and terrible miseries; and though a new kind of navigation was established—the navigation of the open ocean, far away from any possible landmark, a navigation as different as could be conceived from the old method of coasting—yet it remained terribly risky and uncertain throughout the sixteenth century. Therefore many mathematicians endeavoured to solve the problem of determining the position of a ship when at sea. Their suggestions, however, remained entirely fruitless at the time, though in several instances they struck upon principles which are being employed at the present day.
The first country to profit by the discovery of America was Spain, and hence Spain was the first to feel keenly the pinch of the problem. In 1598, therefore, Philip III. offered a prize of 100,000 crowns to any one who would devise a method by which a captain of a vessel could determine his position when out of sight of land. Holland, which had recently started on its national existence, and which was challenging the colonial empire of Spain, followed very shortly after with the offer of a reward of 30,000 florins. Not very long after the offer of these rewards, a master mind did work out a simple method for determining the longitude, a method theoretically complete, though practically it proved inapplicable. This was Galileo, who, with his newly invented telescope, had discovered that Jupiter was attended by four satellites.
At first sight such a discovery, however interesting, would seem to have not the slightest bearing upon the sailor's craft, or upon the commercial progress of one nation or another. But Galileo quickly saw in it the promise of great practical usefulness. The question of the determination of the place of a ship when in the open ocean really resolved itself into this: How could the navigator ascertain at any time what was the true time, say at the port from which he sailed? As already pointed out, it was possible, by observing the height of the sun at noon, or of the pole-star at night, to infer the latitude of the ship. The longitude was the point of difficulty. Now, the longitude may be expressed as the difference between the local time of the place of observation and the local time at the place chosen as the standard meridian. The sailor could, indeed, obtain his own local time by observations of the height of the sun. The sun reached its greatest height at local noon, and a number of observations before and after noon would enable him to determine this with sufficient nicety.
But how was he to determine when he, perhaps, was half-way across the Atlantic, what was the local time at Genoa, Cadiz, Lisbon, Bristol, or Amsterdam, or whatever was the port from which he sailed? Galileo thought out a way by which the satellites of Jupiter could give him this information.
For as they circle round their primary, they pass in turn into its shadow, and are eclipsed by it. It needed, then, only that the satellites should be so carefully watched, that their motions, and, consequently, the times of their eclipses could be foretold. It would follow, then, that if the mariner had in his almanac the local time of the standard city at which a given satellite would enter into eclipse, and he were able to note from the deck of his vessel the disappearance of the tiny point, he would ascertain the difference between the local times of the two places, or, in other words, the difference of their longitudes.
The plan was simplicity itself, but there were difficulties in carrying it out, the greatest being the impossibility of satisfactorily making telescopic observations from the moving deck of a ship at sea. Nor were the observations sufficiently sharp to be of much help. The entry of a satellite into the shadow of Jupiter is in most cases a somewhat slow process, and the moment of complete disappearance would vary according to the size of the telescope, the keenness of the observer's sight, and the transparency of the air.
As the power and commerce of Spain declined, two other nations entered into the contest for the sovereignty of the seas, and with that sovereignty predominance in the New World of America—France and England. The problem of the longitude at sea, or, as already pointed out, what amounts to the same thing, the problem how to determine when at sea the local time at some standard place, became, in consequence, of greater necessity to them.
The standard time would be easily known, if a thoroughly good chronometer which did not change its rate, and which was set to the standard time before starting, was carried on board the ship. This plan had been proposed by Gemma Frisius as early as 1526, but at the time was a mere suggestion, as there were no chronometers or watches sufficiently good for the purpose. There was, however, another method of ascertaining the standard time. The moon moves pretty quickly amongst the stars, and at the present time, when its motions are well known, it is possible to draw up a table of its distances from a number of given stars at definite times for long periods in advance. This is actually done to-day in the Nautical Almanac, the moon's distance from certain stars being given for every three hours of Greenwich time. It is possible, then, by measuring these distances, and making, as in the case of the latitude, certain corrections, to find out the time at Greenwich. In short, the whole sky may be considered as a vast clock set to Greenwich time, the stars being the numbers on the dial face, and the moon the hand (for this clock has only one hand) moving amongst them.
The local apparent time—that is, the time at the place at which the ship itself was—is a simpler matter. It is noon at any place when the sun is due south—or, as we may put it a little differently, when it culminates—that is, when it reaches its highest point.
To find the longitude at sea, therefore, it was necessary to be able to predict precisely the apparent position of the moon in the sky for any time throughout the entire year, and it was also necessary that the places of the stars themselves should be very accurately known. It was therefore to gather the materials for a better knowledge of the motions of the moon and the position of the stars that Greenwich Observatory was founded, whilst the Nautical Almanac was instituted to convey this information to mariners in a convenient form.
This proposal was actually made in the reign of Charles II. by a Frenchman, Le Sieur de Saint-Pierre, who, having secured an introduction to the Duchess of Portsmouth, endeavoured to obtain a reward for his scheme. It would appear that he had simply borrowed the idea from a book which an eminent French mathematician brought out forty years before, without having himself any real knowledge of the subject. But when the matter was brought before the king's notice, he desired some of the leading scientific men of the day to report upon its practicability, and the Rev. John Flamsteed was the man selected for the task. He reported that the scheme in itself was a good one, but impracticable in the then state of science. The king, who, in spite of the evil reputation which he has earned for himself, took a real interest in science, was startled when this was reported to him, and commanded the man who had drawn his attention to these deficiencies 'to apply himself,' as the king's astronomer, 'with the most exact care and diligence to the Rectifying the Tables of the Motions of the Heavens and the Places of the Fixed Stars, in order to find out the so much desired Longitude at Sea, for the perfecting the Art of Navigation.'
This man, the Rev. John Flamsteed, was accordingly appointed first Astronomer Royal at the meagre salary of £100 a year, with full permission to provide himself with the instruments he might require, at his own expense. He followed out the task assigned to him with extreme devotion, amidst many difficulties and annoyances, until his death in 1719. He has been succeeded by seven Astronomers Royal, each of whom has made it his first object to carry out the original scheme of the institution; and the chief purpose of Greenwich Observatory to-day, as when it was founded in 1675, is to observe the motions of the sun, moon, and planets, and to issue accurate star catalogues.
It will be seen, therefore, that the establishment of Greenwich Observatory arose from the actual necessity of the nation. It was an essential step in its progress towards its present position as the first commercial nation. No thoughts of abstract science were in the minds of its founders; there was no desire to watch the cloud-changes on Jupiter, or to find out what Sirius was made of. The Observatory was founded for the benefit of the Royal Navy and of the general commerce of the realm; and, in essence, that which was the sole object of its foundation at the beginning has continued to be its first object down to the present time.
It was impossible that the work of the Observatory should be always confined within the above limits, and it will be my purpose, in the pages which follow, to describe when and how the chief expansions of its programme have taken place. But assistance to navigation is now, and has always been, the dominant note in its management.
For the first century of its existence, the lives of its Astronomers Royal formed practically the history of the Royal Observatory. During this period, the Observatory was itself so small that the Astronomer Royal, with a single assistant, sufficed for the entire work. Everything, therefore, depended upon the ability, energy, and character of the actual director. There was no large organized staff, established routine, or official tradition, to keep the institution moving on certain lines, irrespective of the personal qualities of the chief. It was specially fortunate, therefore, that the first four Astronomers Royal, Flamsteed, Halley, Bradley, and Maskelyne (for Bliss, the immediate successor of Bradley, reigned for so short a time that he may be practically left out of the count), were all men of the most conspicuous ability.
It will be convenient to divide the history of the first seven Astronomers Royal into three sections. In the first, we have the founder, John Flamsteed, a pathetic and interesting figure, whom we seem to know with especial clearness, from the fulness of the memorials which he has left to us. He was succeeded by the man who was, indeed, best fitted to succeed him, but whom he most hated. The second to the sixth Astronomers Royal formed what we might almost speak of as a dynasty, each in turn nominating his successor, who had entered into more or less close connection with the Observatory during the lifetime of the previous director; and the lives of these five may well form the second section. The line was interrupted after the resignation of the sixth Astronomer Royal, and the third section will be devoted to the seventh director, Airy, under whom the Observatory entered upon its modern period of expansion.
'God suffers not man to be idle, although he swim in the midst of delights; for when He had placed His own image (Adam) in a paradise so replenished (of His goodness) with varieties of all things, conducing as well to his pleasure as sustenance, that the earth produced of itself things convenient for both—He yet (to keep him out of idleness) commands him to till, prune, and dress his pleasant, verdant habitation; and to add (if it might be) some lustre, grace, or conveniency to that place, which, as well as he, derived its original from his Creator.'
In these words John Flamsteed begins the first of several autobiographies which he has handed down to us; this particular one being written before he attained his majority, 'to keep myself from idleness and to recreate myself.'
'I was born,' he goes on, 'at Denby, in Derbyshire, in the year 1646, on the 19th day of August, at 7 hours 16 minutes after noon. My father, named Stephen, was the third son of Mr. William Flamsteed, of Little Hallam; my mother, Mary, was the daughter of Mr. John Spateman, of Derby, ironmonger. From these two I derived my beginning, whose parents were of known integrity, honesty, and fortune, as they [were] of equal extraction and ingenuity; betwixt whom I [was] tenderly educated (by reason of my natural weakness, which required more than ordinary care) till I was aged three years and a fortnight; when my mother departed, leaving my father a daughter, then not a month old, with me, then weak, to his fatherly care and provision.'
The weakly, motherless boy became at an early age a voracious reader. At first, he says—
'I began to affect the volubility and ranting stories of romances; and at twelve years of age I first left off the wild ones, and betook myself to read the better sort of them, which, though they were not probable, yet carried no seeming impossibility in the fiction. Afterwards, as my reason increased, I gathered other real histories; and by the time I was fifteen years old I had read, of the ancients, Plutarch's Lives, Appian's and Tacitus's Roman Histories, Holingshed's History of the Kings of England, Davies's Life of Queen Elizabeth, Saunderson's of King Charles the First, Heyling's Geography, and many others of the moderns; besides a company of romances and other stories, of which I scarce remember a tenth at present.'
Flamsteed received his education at the free school at Derby, where he continued until the Whitsuntide of 1662, when he was nearly sixteen years of age. Two years earlier than this, however, a great misfortune fell upon him.
'At fourteen years of age,' he writes, 'when I was nearly arrived to be the head of the free-school, [I was] visited with a fit of sickness, that was followed with a consumption and other distempers, which yet did not so much hinder me in my learning, but that I still kept my station till the form broke up, and some of my fellows went to the Universities; for which, though I was designed, my father thought it not advisable to send me, by reason of my distemper.'
This was a keen disappointment to him, but seems to have really been the means of determining his career. The sickly, suffering boy could not be idle, though 'a day's short reading caused so violent a headache;' and a month or two after he had left school, he had a book lent to him—Sacrobosco's De Sphæra, in Latin—which was the beginning of his mathematical studies. A partial eclipse of the sun in September of the same year seems to have first drawn his attention to astronomical observation, and during the winter his father, who had himself a strong passion for arithmetic, instructed him in that science.
It was astonishing how quickly his appetite for his new subjects grew. The Art of Dialling, the calculation of tables of the sun's altitudes for all hours of the day, and for different latitudes, and the construction of a quadrant—'of which I was not meanly joyful'—were the occupations of this winter of illness.
In 1664 he made the acquaintanceship of two friends, Mr. George Linacre and Mr. William Litchford; the former of whom taught him to recognize many of the fixed stars, whilst the latter was the means of his introduction to a knowledge of the motions of the planets.
'I had now completed eighteen years, when the winter came on, and thrust me again into the chimney; whence the heat and dryness of the preceding summer had happily once before withdrawn me.'
The following year, 1665, was memorable to him 'for the appearance of the comet,' and for a journey which he made to Ireland to be 'stroked' for his rheumatic disorder by Valentine Greatrackes, a kind of mesmerist, who had the repute of effecting wonderful cures. The journey, of which he gives a full and vivid account, occupied a month; but though he was a little better, the following winter brought him no permanent benefit.
But, ill or well, he pressed on his astronomical studies. A large partial eclipse of the sun was due the following June; he computed the particulars of it for Derby, and observed the eclipse itself to the best of his ability. He argued out for himself 'the equation of time'; the difference, that is, between time as given by the actual sun, or 'apparent time,' and that given by a perfect clock, or 'mean time.' He drew up a catalogue of seventy stars, computing their right ascensions, declinations, longitudes, and latitudes for the year 1701; he attempted to determine the inclination of the ecliptic, the mean length of the tropical year, and the actual distance of the earth from the sun. And these were the recreations of a sickly, suffering young man, not yet twenty-one years of age, and who had only begun the study of arithmetic, such as fractions and the rule of three, four years previously!
His next attempt was almanac-making, in the which he improved considerably upon those current at the time. His almanac for 1670 was rejected, however, and returned to him, and, not to lose his whole labour, he sent his calculations of an eclipse of the sun, and of five occultations of stars by the moon, which he had undertaken for the almanac, to the Royal Society. He sent the paper anonymously, or, rather, signed it with an anagram, 'In mathesi a sole fundes,' for 'Johannes Flamsteedius.' His covering letter ends thus:—
'Excuse, I pray you, this juvenile heat for the concerns of science and want of better language, from one who, from the sixteenth year of his age to this instant, hath only served one bare apprenticeship in these arts, under the discouragement of friends, the want of health, and all other instructors except his better genius.'
This letter was dated November 4, 1669, and on January 14, Mr. Oldenburg, the secretary of the Society, replied to him in a letter which the young man cannot but have felt encouraging and flattering to the highest degree.
'Though you did what you could to hide your name from us,' he writes, 'yet your ingenious and useful labours for the advancement of Astronomy addressed to the noble President of the Royal Society, and some others of that illustrious body, did soon discover you to us, upon our solicitous inquiries after their worthy author.'
And after congratulating him upon his skill, and encouraging him to furnish further similar papers, he signs himself, 'Your very affectionate friend and real servant'—no unmeaning phrase, for the friendship then commenced ceased only with Oldenburg's life.
The following June, his father, pleased with the notice that some of the leading scientific men of the day were taking of his son, sent him up to London, that he might be personally acquainted with them; and he then was introduced to Sir Jonas Moore, the Surveyor of the Ordnance, who made him a present of Townley's micrometer, and promised to furnish him with object-glasses for telescopes at moderate rates.
On his return journey he called at Cambridge, where he visited Dr. Barrow and Newton, and entered his name in Jesus College.
It was not until the following year, 1671, that he was enabled to complete his own observatory, as he had had to wait long for the lenses which Sir Jonas Moore and Collins had promised to procure for him. He still laboured under several difficulties, in that he had no good means for measuring time, pendulum clocks not then being common. He, therefore, with a practical good sense which was characteristic, refrained from attempting anything which lay out of his power to do well, and he devoted himself to such observations as did not require any very accurate knowledge of the time. At the same time, he was careful to ascertain the time of his observations as closely as possible, by taking the altitudes of the stars.
The next four years seem to have passed exceedingly pleasantly to him. The notes of ill-health are few. He was making rapid progress in his acquaintanceship with the work of other astronomers, particularly with those of the three marvellously gifted young men—Horrox, Crabtree, and Gascoigne—who had passed away shortly before his own birth. He was making new friends in scientific circles, and, in particular, Sir Jonas Moore was evidently esteeming him more and more highly. In 1674 he became more intimate with Newton, the occasion which led to this acquaintanceship being the amusing one, that his assistance was asked by Newton, who had found himself unable to adjust a microscope, having forgotten its object-glass—not the only instance of the great mathematician's absent-mindedness.
The same year he took his degree of A.M. at Cambridge, designing to enter the Church; but Sir Jonas Moore was extremely anxious to give him official charge of an observatory, and was urging the Royal Society to build an astronomical observatory at Chelsea College, which then belonged to that body. He therefore came up to London, and resided some months with Sir Jonas Moore at the Tower. But shortly after his coming up to London, 'an accident happened,' to use his own expression, that hastened, if it did not occasion, the building of Greenwich Observatory.
'A Frenchman that called himself Le Sieur de St. Pierre, having some small skill in astronomy, and made an interest with a French lady, then in favour at Court, proposed no less than the discovery of the Longitude, and had procured a kind of Commission from the King to the Lord Brouncker, Dr. Ward (Bishop of Salisbury), Sir Christopher Wren, Sir Charles Scarborough, Sir Jonas Moore, Colonel Titus, Dr. Pell, Sir Robert Murray, Mr. Hook, and some other ingenious gentlemen about the town and Court, to receive his proposals, with power to elect, and to receive into their number, any other skilful persons; and having heard them, to give the King an account of them, with their opinion whether or no they were practicable, and would show what he pretended. Sir Jonas Moore carried me with him to one of their meetings, where I was chosen into their number; and, after, the Frenchman's proposals were read, which were:
'(1) To have the year and day of the observations.
'(2) The height of two stars, and on which side of the meridian they appeared.
'(3) The height of the moon's two limbs.
'(4) The height of the pole—all to degrees and minutes.
'It was easy to perceive, from these demands, that the sieur understood not that the best lunar tables differed from the heavens; and that, therefore, his demands were not sufficient for determining the longitude of the place where such observations were, or should be, made, from that to which the lunar tables were fitted, which I represented immediately to the company. But they, considering the interests of his patroness at Court, desired to have him furnished according to his demands. I undertook it; and having gained the moon's true place by observations made at Derby, February 23, 1672, and November 12, 1673, gave him observations such as he demanded. The half-skilled man did not think they could have been given him, and cunningly answered "They were feigned." I delivered them to Dr. Pell, February 19, 1674–5, who, returning me his answer some time after, I wrote a letter in English to the commissioners, and another in Latin to the sieur, to assure him they were not feigned, and to show them that, if they had been, yet if we had astronomical tables that would give us the two places of the fixed stars and the moon's true places, both in longitude and latitude, nearer than to half a minute, we might hope to find the longitude of places by lunar observations, but not by such as he demanded. But that we were so far from having the places of the fixed stars true, that the Tychonic Catalogues often erred ten minutes or more; that they were uncertain to three or four minutes, by reason that Tycho assumed a faulty obliquity of the ecliptic, and had employed only plain sights in his observations: and that the best lunar tables differ one-quarter, if not one-third, of a degree from the heavens; and lastly, that he might have learnt better methods than he proposed, from his countryman Morin, whom he had best consult before he made any more demands of this nature.'
This was in effect to tell St. Pierre that his proposal was neither original nor practicable. If St. Pierre had but consulted Morin's writings (Morin himself had died more than eighteen years before), he would have known that practically the same proposal had been laid before Cardinal Richelieu in 1634, and had been rejected, as quite impracticable in the then state of astronomical knowledge. Possibly Flamsteed meant further to intimate that St. Pierre had simply stolen his method from Morin, hoping to trade it off upon the government of another country; in which case he would no doubt regard Flamsteed's letter as a warning that he had been found out.
Flamsteed continues:—