The Project Gutenberg eBook, The Royal Observatory Greenwich, by E. Walter (Edwared Walter) Maunder

FLAMSTEED, THE FIRST ASTRONOMER ROYAL.
(From the portrait in the 'Historia Cœlestis.')

THE
ROYAL OBSERVATORY
GREENWICH
A GLANCE AT ITS HISTORY
AND WORK

BY

E. WALTER MAUNDER, F.R.A.S.

WITH MANY PORTRAITS AND ILLUSTRATIONS FROM
OLD PRINTS AND ORIGINAL PHOTOGRAPHS

LONDON

THE RELIGIOUS TRACT SOCIETY

56 Paternoster Row, and 65 St. Paul's Churchyard
1900

LONDON:
PRINTED BY WILLIAM CLOWES AND SONS, LIMITED,
STAMFORD STREET AND CHARING CROSS.

PREFACE

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.)

CONTENTS

LIST OF ILLUSTRATIONS

GENERAL VIEW OF THE OBSERVATORY BUILDINGS FROM THE NEW DOME.
(From a photograph by Mr. Lacey.)

THE ROYAL OBSERVATORY

GREENWICH

CHAPTER I

INTRODUCTION

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.

'For the Lord our God most High,
He hath made the deep as dry;
He has smote for us a pathway,
To the ends of all the earth.'

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

'Swift shuttles of an empire's loom,
That weave us main to main.'

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.

CHAPTER II

FLAMSTEED

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:—

'I heard no more of the Frenchman after this; but was told that, my letters being shown King Charles, he startled at the assertion of the fixed stars' places being false in the catalogue; said, with some vehemence, "He must have them anew observed, examined, and corrected, for the use of his seamen;" and further (when it was urged to him how necessary it was to have a good stock of observations taken for correcting the motions of the moon and planets), with the same earnestness, "he must have it done." And when he was asked Who could, or who should do it? "The person (says he) that informs you of them." Whereupon I was appointed to it, with the incompetent allowance aforementioned; but with assurances, at the same time, of such further additions as thereafter should be found requisite for carrying on the work.'

FLAMSTEED'S SEXTANT.
(From an engraving in the 'Historia Cœlestis.')

Thus, in his twenty-ninth year, John Flamsteed became the first Astronomer Royal. In many ways he was an ideal man for the post. In the twelve years which had passed since he left school he had accomplished an amazing amount of work. Despite his constant ill-health and severe sufferings, and the circumstance—which may be inferred from many expressions in his autobiographies—that he assisted his father in his business, he had made himself master, perhaps more thoroughly than any of his contemporaries, of the entire work of a practical astronomer as it was then understood. He was an indefatigable computer; the calculation of tables of the motions of the moon and planets, which should as faithfully as possible represent their observed positions, had had an especial attraction for him, and, as has been already mentioned, some years before his appointment he had drawn up a catalogue of stars, based upon the observations of Tycho Brahe. More than that, he had not been a merely theoretical worker, he had been a practical observer of very considerable skill, and, in the dearth of suitable instruments, had already made one or two for himself, and had contemplated the making of others. In his first letter to Sir Jonas Moore he asks for instruction as to the making of object-glasses for telescopes, for he was quite prepared to set about the task of making his own. In addition to his tireless industry, which neither illness nor suffering could abate, he was a man of singularly exact and business-like habits. The precision with which he preserves and records the dates of all letters received or sent is an illustration of this. On the other hand, he had the defects of his circumstances and character. His numerous autobiographical sketches betray him, not indeed as a conceited man, in the ordinary sense of the word, but as an exceedingly self-conscious one. Devout and high-principled he most assuredly was, but, on the other hand, he shows in almost every line he wrote that he was one who could not brook anything like criticism or opposition.

Such a man, however efficient, was little likely to be happy as the first incumbent of a new and important government post; but there was another circumstance which was destined to cause him greater unhappiness still.

If we believe, as surely we must, that not only the moral and the physical progress of mankind is watched over and controlled by God's good Providence, but its intellectual progress as well, then there can be no doubt that John Flamsteed was raised up at this particular time, not merely to found Greenwich Observatory, and to assist the solution of the problem of the longitude at sea, but also, and chiefly, to become the auxiliary to a far greater mind, the journeyman to a true master-builder. But for the founding of Greenwich Observatory, and for John Flamsteed's observations made therein, the working out of Newton's grand theory of gravitation must have been hindered, and its acceptance by the men of science of his time immensely delayed. We cannot regard as accidental the combination, so fortunate for us, of Newton, the great world-genius, to work out the problem, of Flamsteed, the painstaking observer, to supply him with the materials for his work, and of the newly-founded institution, Greenwich Observatory, where Flamsteed was able to gather those materials together. This is the true debt that we owe to Flamsteed, that, little as he understood the position in which he had been placed from the standpoint from which we see it to-day, yet, to the extent of his ability, and as far as he conceived it in accordance with his duty, he gave Newton such assistance as he could.

This is how we see the matter to-day. It wore a very different aspect in Flamsteed's eyes; and the two following documents, the one, the warrant founding the Observatory and making him Astronomer Royal; the other, the warrant granting him a salary, will go far to explain his position in the matter. He had a high-sounding, official position, which could not fail to impress him with a sense of importance; whilst his salary was so insufficient that he naturally regarded himself as absolute owner of his own work.

'Warrant for the Payment of Mr. Flamsteed's Salary.

'Charles Rex.

'Whereas, we have appointed our trusty and well-beloved John Flamsteed, Master of Arts, our astronomical observator, forthwith to apply himself 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, so as to find out the so-much-desired longitude of places for the perfecting the art of navigation, Our will and pleasure is, and we do hereby require and authorize you, for the support and maintenance of the said John Flamsteed, of whose abilities in astronomy we have very good testimony, and are well satisfied, that from time to time you pay, or cause to be paid, unto him, the said John Flamsteed, or his assigns, the yearly salary or allowance of one hundred pounds per annum; the same to be charged and borne upon the quarter-books of the Office of the Ordnance, and paid to him quarterly, by even and equal portions, by the Treasurer of our said office, the first quarter to begin and be accompted from the feast of St. Michael the Archangel last past, and so to continue during our pleasure. And for so doing, this shall be as well unto you, as to the Auditors of the Exchequer, for allowing the same, and all other our officers and ministers whom it may concern, a full and sufficient warrant.

'Given at our Court at Whitehall, the 4th day of March, 1674-5.

'By his Majesty's Command,

'J. Williamson.

'To our right-trusty and well-beloved Counsellor, Sir Thomas Chichely, Knt., Master of our Ordnance, and to the Lieutenant-General of our Ordnance, and to the rest of the Officers of our Ordnance, now and for the time being, and to all and every of them.'

'Warrant for Building the Observatory.

'Charles Rex.

'Whereas, in order to the finding out of the longitude of places for perfecting navigation and astronomy, we have resolved to build a small observatory within our park at Greenwich, upon the highest ground, at or near the place where the Castle stood, with lodging-rooms for our astronomical observator and assistant, Our will and pleasure is, that according to such plot and design as shall be given you by our trusty and well-beloved Sir Christopher Wren, Knight, our surveyor-general of the place and scite of the said observatory, you cause the same to be fenced in, built and finished with all convenient speed, by such artificers and workmen as you shall appoint thereto, and that you give order unto our Treasurer of the Ordnance for the paying of such materials and workmen as shall be used and employed therein, out of such monies as shall come to your hands for old and decayed powder, which hath or shall be sold by our order of the 1st of January last, provided that the whole sum, so to be expended or paid, shall not exceed five hundred pounds; and our pleasure is, that all our officers and servants belonging to our said park be assisting to those that you shall appoint, for the doing thereof, and for so doing, this shall be to you, and to all others whom it may concern, a sufficient warrant.

'Given at our Court at Whitehall, the 22nd day of June, 1675, in the 27th year of our reign.

'By his Majesty's Command,

'J. Williamson.

'To our right-trusty and well-beloved Counsellor, Sir Thomas Chichely, Knt., Master-General of our Ordnance.'

The first question that arose, when it had been determined to found the new Observatory, was where it was to be placed. Hyde Park was suggested, and Sir Jonas Moore recommended Chelsea College, where he had already thought of establishing Flamsteed in a private observatory. Fortunately, both these localities were set aside in favour of one recommended by Sir Christopher Wren. There was a small building on the top of the hill in the Royal Park of Greenwich belonging to the Crown, and which was now of little or no use. Visible from the city, and easily accessible by that which was then the best and most convenient roadway, the river Thames, it was yet so completely out of town as to be entirely safe from the smoke of London. In Greenwich Park, too, but on the more easterly hill, Charles I. had contemplated setting up an observatory, but the pressure of events had prevented him carrying out his intention. A further practical advantage was that materials could be easily transported thither. The management of public affairs under Charles II. left much to be desired in the matter of efficiency and economy, and it was not very easy to procure what was wanted for the erection of a purely scientific building. However, the matter was arranged. A gate-house demolished in the Tower supplied wood; iron, and lead, and bricks were supplied from Tilbury Fort, and these could be easily brought by water to the selected site. The sum of £500, actually £520, was further allotted from the results of a sale of spoilt gunpowder; and with these limited resources Greenwich Observatory was built.

The foundation-stone was laid August 10, 1675, and Flamsteed amused himself by drawing the horoscope of the Observatory, a fact which—in spite of his having written across the face of the horoscope Risum teneatis amici? (Can you keep from laughter, my friends?), and his having two or three years before written very severely against the imposture of astrology—has led some modern astrologers to claim him as a believer in their cult. He actually entered into residence July 10, 1676.

THE ROYAL OBSERVATORY IN FLAMSTEED'S DAY.
(From an engraving in the 'Historia Cœlestis.')

His position was not a bright one. The Government had, indeed, provided him with a building for his observatory, and a small house for his own residence, but he had no instrument and no assistant. The first difficulty was partly overcome for the moment by gifts or loans from Sir Jonas Moore, and by one or two small loans from the Royal Society. The death of this great friend and patron, four years after the founding of the Observatory, and only three years after his entering into residence, deprived him of several of these; it was with difficulty that he maintained against Sir Jonas' heirs his claim to the instruments which Sir Jonas had given him. There was nothing for him to do but to make his instruments himself, and in 1683 he built a mural quadrant of fifty inches radius. His circumstances improved the following year, when Lord North gave him the living of Burstow, near Horley, Surrey, Flamsteed having received ordination almost at the time of his appointment to the Astronomer Royalship. We have little or no account of the way in which he fulfilled his duties as a clergyman. Evidently he considered that his position as Astronomer Royal had the first claim upon him. At the same time, comparatively early in life he had expressed his desire to fill the clerical office, and he was a man too conscientious to neglect any duty that lay upon him. That in spite of his feeble health he often journeyed to and fro between Burstow and Greenwich we know; and we may take it as certain that at a time when the standard of clerical efficiency was extremely low, he was not one of those who

'For their bellies' sake,
Creep and intrude and climb into the fold.'

His chief source of income, however, seems to have been the private pupils whom he took in mathematics and astronomy. These numbered in the years 1676 to 1709 no fewer than 140; and as many of them were of the very first and wealthiest families in the kingdom, the gain to Flamsteed in money and influence must have been considerable. But it was most distasteful work. It was in no sense that which he felt to be his duty, and which he had at heart. It was undertaken from sheer, hard necessity, and he grudged bitterly the time and strength which it diverted from his proper calling.

How faithfully he followed that, one single circumstance will show. In the thirteen years ending 1689, he made 20,000 observations, and had revised single-handed the whole of the theories and tables of the heavenly bodies then in use.

In 1688 the death of his father brought him a considerable accession of means, and, far more important, the assistance of Abraham Sharp,[1] the first and most distinguished of the long list of Greenwich assistants, men who, though far less well known than the Astronomers Royal, have contributed scarcely less in their own field to the high reputation of the Observatory.

Sharp was not only a most careful and indefatigable calculator, he was what was even more essential for Flamsteed—a most skilful instrument-maker; and he divided for him a new mural arc of 140° and seven feet radius, with which he commenced operations on December 12, 1689. Above all, Sharp became his faithful and devoted friend and adherent, and no doubt his sympathy strengthened Flamsteed to endure the trouble which was at hand.

That trouble began in 1694, when Newton visited the Royal Observatory. At that time Flamsteed, though he had done so much, had published nothing, and Newton, who had made his discovery of the laws of gravitation some few years before, was then employed in deducing from them a complete theory of the moon's motion. This work was one of absolutely first importance. In the first place and chiefly, upon the success with which it could be carried out, depended undoubtedly the acceptance of the greatest discovery which has yet been made in physical science. Secondarily—and this should, and no doubt did, appeal to Flamsteed—the perfecting of our knowledge of the movements of the moon was a primary part of the very work which he was commissioned to do as Astronomer Royal. Newton was, therefore, anxious beyond everything to receive the best possible observations of the moon's places, and he came to Flamsteed, as to the man from whom he had a right to expect to receive a supply of them. At first Flamsteed seems to have given these as fully as he was able; but it is evident that Newton chafed at the necessity for these frequent applications to Flamsteed, and to the constant need of putting pressure upon him. Flamsteed, on the other hand, as clearly evidently resented this continual demand. Feeling, as he keenly did, that, though he had been named Astronomer Royal, he had been left practically entirely without support; his instruments were entirely his own, either made or purchased by himself; his nominal salary of £100 was difficult to get, and did not nearly cover the actual current expenses of his position, he not unnaturally regarded his observations as his own exclusive property. He had a most natural dislike for his observations to be published, except after such reduction as he himself had carried through, and in the manner which he himself had chosen. The idea which was ever before him was that of carrying out a single great work that should not only be a monument to his own industry and skill, but should also raise the name of England amongst scientific nations. He complained of it, therefore, both as a personal wrong and an injury to the country when some observations of Cassini's were combined with some observations of his own in order to deduce a better orbit for a comet.

Unknown to himself, therefore, he was called upon to decide a question that has proved fundamental to the policy of Greenwich Observatory, and he decided it wrongly—the question of publication. Newton had urged upon him as early as 1691 that he should not wait until he had formed an exhaustive catalogue of all the brighter stars, but that he should publish at once a catalogue of a few, which might serve as standards; but Flamsteed would not hear of it. He failed to see that his office had been created for a definite practical purpose, not for the execution of some great scheme, however important to science. All his work of thirty years had done nothing to forward navigation so long as he published nothing. But if, year by year, he had published the places of the moon and of a few standard stars, he would have advanced the art immensely and yet have not hindered himself from eventually bringing out a great catalogue. No doubt the little incident of Newton's difficulty with the microscope, of which he had forgotten the object-glass, had given Flamsteed a low opinion of Newton's qualifications as a practical astronomer. If so, he was wrong, for Newton's insight into practical matters was greater than Flamsteed's own, and his practical skill was no less, though his absent-mindedness might occasionally lead him into an absurd mistake.

The following extract from Flamsteed's own 'brief History of the Observatory' gives an account of his view of Newton's action towards him in desiring the publication of his star catalogue, and at the same time it illustrates Flamsteed's touchy and suspicious nature.

'Whilst Mr. Flamsteed was busied in the laborious work of the catalogue of the fixed stars, and forced often to watch and labour by night, to fetch the materials for it from the heavens, that were to be employed by day, he often, on Sir Isaac Newton's instances, furnished him with observations of the moon's places, in order to carry on his correction of the lunar theory. A civil correspondence was carried on between them; only Mr. Flamsteed could not but take notice that as Sir Isaac was advanced in place, so he raised himself in his conversation and became more magisterial. At last, finding that Mr. Flamsteed had advanced far in his designed catalogue by the help of his country calculators, that he had made new lunar tables, and was daily advancing on the other planets, Sir Isaac Newton came to see him (Tuesday, April 11, 1704); and desiring, after dinner, to be shown in what forwardness his work was, had so much of the catalogue of the fixed stars laid before him as was then finished; together with the maps of the constellations, both those drawn by T. Weston and P. Van Somer, as also his collation of the observed places of Saturn and Jupiter, with the Rudolphine numbers. Having viewed them well, he told Mr. Flamsteed he would (i.e. he was desirous to) recommend them to the Prince privately. Mr. Flamsteed (who had long been sensible of his partiality, and heard how his two flatterers cried Sir Isaac's performances up, was sensible of the snare in the word privately) answered that would not do; and (upon Sir Isaac's demanding "why not?") that then the Prince's attendants would tell him these were but curiosities of no great use, and persuade him to save that expense, that there might be the more for them to beg of him: and that the recommendation must be made publicly, to prevent any such suggestions. Sir Isaac apprehended right, that he was understood, and his designs defeated: and so took his leave not well satisfied with the refusal.

'It was November following ere Mr. Flamsteed heard from him any more: when, considering with himself that what he had done was not well understood, he set himself to examine how many folio pages his work when printed would fill; and found upon an easy computation that they would at least take up 1400. Being amazed at this, he set himself to consider them more seriously; drew up an estimate of them; and, to obviate the misrepresentations of Dr. S[loane] and some others, who had given out that what he had was inconsiderable, he delivered a copy of the estimate to Mr. Hodgson, then lately chosen a member of the Royal Society, with directions to deliver it to a friend, who he knew would do him justice; and, on this fair account, obviate those unjust reports which had been studiously spread to his prejudice. It happened soon after, Mr. Hodgson being at a meeting, spied this person there, at the other side of the room; and therefore gave the paper to one that stood in some company betwixt them, to be handed to him. But the gentleman, mistaking his request, handed to the Secretary [Dr. Sloane], who, being a Physician, and not acquainted with astronomical terms, did not read it readily. Whereupon another in the company took it out of his hands; and, having read it distinctly, desired that the works therein mentioned might be recommended to the Prince; the charge of printing them being too great either for the author or the Royal Society. Sir Isaac closed in with this.'

THE 'CAMERA STELLATA' IN FLAMSTEED'S TIME.
(From an engraving in the 'Historia Cœlestis.')

The work was in consequence recommended to Prince George of Denmark, the Queen's Consort; but it was not till November 10, 1705, that the contract for the printing was signed. Two years later, the observations which he had made with his sextant in his first thirteen years of office were printed. Then came the difficulty of the catalogue. It was not complete to Flamsteed's satisfaction, and he was most unwilling to let it pass out of his hands. However, two manuscripts, comprising some three-quarters of the whole, were deposited with referees, the first of these being sealed up. The seal was broken with Flamsteed's concurrence; but the fact that it had been so broken was made by him the subject of bitter complaint later. At this critical juncture Prince George died, and a stop was put to the progress of the printing. Two years more elapsed without any advance being made, and then, in order to check any further obstruction, a committee of the Royal Society was appointed as a Board of Visitors to visit and inspect the Observatory, and so maintain a control over the Astronomer Royal. This was naturally felt by so sensitive a man as Flamsteed as a most intolerable wrong, and when he found that the printing of his catalogue had been placed in the hands of Halley as editor, a man for whom he had conceived the most violent distrust, he absolutely refused to furnish the Visitors with any further material. This led to, perhaps, the most painful scene in the lives either of Newton or Flamsteed. Flamsteed was summoned to meet the Council of the Royal Society at their rooms in Crane Court. A quorum was not present, and so the interview was not official, and no record of it is preserved in the archives. Flamsteed has himself described it with great particularity in more than one document, and it is only too easy to understand the scene that took place. Newton was a man who had an absolutely morbid dread of anything like controversy, and over and over again would have preferred to have buried his choicest researches, rather than to have encountered the smallest conflict of the kind. He was perhaps, therefore, the worst man to deal with a high-principled, sensitive, and obstinate man who was in the wrong, and yet who had been so hardly dealt with that it was most natural for him to think himself wholly in the right. Flamsteed adhered absolutely to his position, from which it is clear it would have been extremely difficult for the greatest tact and consideration to have dislodged him. Newton, on his part, simply exerted his authority, and, that failing, was reduced to the miserable extremity of calling names. The scene is described by Flamsteed himself, in a letter to Abraham Sharp, as follows:—

'I have had another contest with the President[2] of the Royal Society, who had formed a plot to make my instruments theirs; and sent for me to a Committee, where only himself and two physicians (Dr. Sloane, and another as little skilful as himself) were present. The President ran himself into a great heat, and very indecent passion. I had resolved aforehand his kn—sh talk should not move me; showed him that all the instruments in the Observatory were my own; the mural arch and voluble quadrant having been made at my own charge, the rest purchased with my own money, except the sextant and two clocks, which were given me by Sir Jonas Moore, with Mr. Towneley's micrometer, his gift, some years before I came to Greenwich. This nettled him; for he has got a letter from the Secretary of State for the Royal Society to be Visitors of the Observatory, and he said, "as good have no observatory as no instruments." I complained then of my catalogue being printed by Raymer, without my knowledge, and that I was robbed of the fruit of my labours. At this he fired, and called me all the ill names, puppy, etc., that he could think of. All I returned was, I put him in mind of his passion, desired him to govern it, and keep his temper: this made him rage worse, and he told me how much I had received from the Government in thirty-six years I had served. I asked what he had done for the £500 per annum that he had received ever since he had settled in London. This made him calmer; but finding him going to burst out again, I only told him my catalogue, half finished, was delivered into his hands, on his own request, sealed up. He could not deny it, but said Dr. Arbuthnott had procured the Queen's order for opening it. This, I am persuaded, was false; or it was got after it had been opened. I said nothing to him in return; but, with a little more spirit than I had hitherto showed, told them that God (who was seldom spoken of with due reverence in that meeting) had hitherto prospered all my labours, and I doubted not would do so to a happy conclusion; took my leave and left them. Dr. Sloane had said nothing all this while; the other Doctor told me I was proud, and insulted the President, and ran into the same passion with the President. At my going out, I called to Dr. Sloane, told him he had behaved himself civilly, and thanked him for it. I saw Raymer after, drank a dish of coffee with him, and told him, still calmly, of the villany of his conduct, and called it blockish. Since then they let me be quiet; but how long they will do so I know not, nor am I solicitous.'

The Visitors continued the printing, Halley being the editor, and the work appeared in 1712 under the title of Historia Cœlestis. This seemed to Flamsteed the greatest wrong of all. The work as it appeared seemed to him so full of errors, wilfully or accidentally inserted, as to be the greatest blot upon his fair fame, and he set himself, though now an old man, to work it out de novo and at his own expense. To that purpose he devoted the remaining seven years of his life. Few things can be more pathetic than the letters which he wrote in that period referring to it. He was subject to the attacks of one of the cruelest of all diseases—the stone; he was at all times liable to distracting headaches. He had been, from his boyhood, a great sufferer from rheumatism, and yet, in spite of all, he resolutely pushed on his self-appointed task. The following extract from one of his letters will give a more vivid idea of the brave old man than much description:—

'I can still, I praise God for it, walk from my door to the Blackheath gate and back, with a little resting at some benches I have caused to be set up betwixt them. But I found myself so tired with getting up the hill when I return from church, that at last I have bought a sedan, and am carried thither in state on Sunday mornings and back; I hope I may employ it in the afternoons, though I have not hitherto, by reason of the weather is too cold for me.'

After the death of Queen Anne, a change in the ministry enabled him to secure that three hundred copies of the total impression of four hundred of the Historia Cœlestis were handed over to him. These, except the first volume, containing his sextant observations (which had received his own approval), he burned, 'as a sacrifice to heavenly truth.' His own great work had advanced so far that the first volume was printed, and much of the second, when he himself died, on the last day of 1719. He was buried in the chancel of Burstow Church.

The completion of his work took ten years more; a work of piety and regard on the part of his assistant, Joseph Crosthwait.

When compared with the catalogues that have gone before, it was a work of wonderful accuracy. Nevertheless, as Caroline Herschel showed, nearly a century later, not a few errors had crept into it. Some of the stars are non-existent, others have been catalogued in more than one constellation; important stars have been altogether omitted. Perhaps the most serious fault arises from the neglect of Flamsteed to accept from Newton a practical hint, namely, to read the barometer and thermometer at the time of his observations. Nevertheless, the work accomplished was not only wonderful under the untoward conditions in which Flamsteed was placed; it was wonderful in itself, winning from Airy the following high encomium:—

'In regard not only to accuracy of observation, and to detail in publication of the methods of observing, but also to steadiness of system followed through many years, and to completeness of calculation of the useful results deduced from the observations, this work may shame any other collection of observations in this or any other country.'

This catalogue was not Flamsteed's only achievement. He had determined the latitude of the Observatory, the obliquity of the ecliptic, and the position of the equinoctial points. He thought out an original method of obtaining the absolute right ascensions of stars by differential observations of the places of the stars and the sun near to both equinoxes. He had revised and improved Horrox's theory of the lunar motions, which was by far the best existing in Flamsteed's day. He showed the existence of the long inequality of Jupiter and Saturn; that is to say, the periodic influence which they exercise upon each other. He determined the time in which the sun rotates on its axis, and the position of that axis. He observed an apparent movement of the stars in the course of a year, which he ascribed, though erroneously, to the stellar parallax, and which was explained by the third Astronomer Royal, Bradley.

Flamsteed not only met with harsh treatment during his lifetime; he has not yet received, except from a few, anything like the meed of appreciation which is his just due; but, at least, his successors in the office have not forgotten him. They have been proud that their official residence should be known as Flamsteed House, and his name is inscribed over the main entrance of the latest and finest of the Observatory buildings, and his bust looks forth from its front towards the home where he laboured so devotedly for nearly fifty years. But he has received little honour, save at Greenwich, and—in spite of the proverb—in his other home, the village of Burstow, in Surrey, of which he was for many years the rector. Here a stained glass window representing, appropriately, the Adoration of the Magi, has been recently set up to his memory, largely through the interest taken in his history by an amateur astronomer of the neighbourhood, Mr. W. Tebb, F.R.A.S.

No instrument of Flamsteed's remains in the Observatory, his wife removing them after his death. But we may consider his principal instrument, the mural quadrant made for him by Abraham Sharp, as represented by the remains of a quadrant by the same artist, which was presented to the Observatory by the Rev. N. S. Heineken, in 1865, and now hangs over the door of the transit room.

CHAPTER III

HALLEY AND HIS SUCCESSORS

There is no need to give the lives of the succeeding Astronomers Royal so fully as that of Flamsteed. Not that they were inferior men to him; on the contrary, there can be little doubt that we ought to reckon some of them as his superiors, but, in the case of several, their best work was done apart from Greenwich Observatory, and before they came to it.

This was particularly the case with Edmund Halley. Born on October 29, 1656, he was ten years the junior of Flamsteed. Like Flamsteed, he came of a Derbyshire family, though he was born at Haggerston, in the parish of St. Leonard's, Shoreditch. He was educated at St. Paul's School, where he made very rapid progress, and already showed the bent of his mind. He learnt to make dials; he made himself so thoroughly acquainted with the heavens that it is said, 'If a star were displaced in the globe he would presently find it out,' and he observed the changes in the direction of the mariner's compass. In 1673 he went to Queen's College, Oxford, where he observed a sunspot in July and August, 1676, and an occultation of Mars. This was not his first astronomical observation, as, in June, 1675, he had observed an eclipse of the moon from his father's house in Winchester Street.

EDMUND HALLEY.
(From an old print.)

A much wider scheme of work than such merely casual observations now entered his mind, possibly suggested to him by Flamsteed's appointment to the direction of the new Royal Observatory. This was to make a catalogue of the southern stars. Tycho's places for the northern stars were defective enough, but there was no catalogue at all of stars below the horizon of Tycho's observatory. Here, then, was a field entirely unworked, and young Halley was so eager to enter upon it that he would not wait at Oxford to obtain his degree, but was anxious to start at once for the southern hemisphere.

His father, who was wealthy and proud of his gifted son, strongly supported him in his project. The station he selected was St. Helena, an unfortunate choice, as the skies there were almost always more or less clouded, and rain was frequent during his stay. However, he remained there a year and a half, and succeeded in making a catalogue of 341 stars. This catalogue was finally reduced by Sharp, and included in the third volume of Flamsteed's Historia Cœlestis.

In 1678 he was elected Fellow of the Royal Society, and the following year he was chosen to represent that society in a discussion with Hevelius. The question at issue was as to whether more accurate observations of the place of a star could be obtained by the use of sights without optical assistance, or by the use of a telescope. The next year he visited the Paris Observatory, and, later in the same tour, the principal cities of the Continent.

Not long after his return from this tour, Halley was led to that undertaking for which we owe him the greatest debt of gratitude, and which must be regarded as his greatest achievement.

Some fifty years before, the great Kepler had brought out the third of his well-known laws of planetary motion. These laws stated that the planets move round the sun in ellipses, of which the sun occupies one of the foci; that the straight line joining any planet with the sun moves over equal areas of space in equal periods of time; and, lastly, that the squares of the times in which the several planets complete a revolution round the sun are proportional to the cubes of their mean distances from it. These three laws were deduced from actual examination of the movements of the planets. Kepler did not work out any underlying cause of which these three laws were the consequence.

But the desire to find such an underlying cause was keen amongst astronomers, and had given rise to many researches. Amongst those at work on the subject was Halley himself. He had seen, and been able to prove, that if the planets moved in circles round the sun, with the sun in the centre, then the law of the relation between the times of revolution and the distances of the planets would show that the attractive force of the sun varied inversely as the square of the distance. The actual case, however, of motion in an ellipse was too hard for him, and he could not deal with it. Halley therefore went up to Cambridge to consult Newton, and, to his wonder and delight, found that the latter had already completely solved the problem, and had proved that Kepler's three laws of planetary motion were summed up in one, namely, that the sun attracted the planets to it with a force inversely proportional to the square of the distance.

Halley was most enthusiastic over this great discovery, and he at once strongly urged Newton to publish it. Newton's unwillingness to do so was great, but at length Halley overcame his reluctance; and the Royal Society not being able at the time to afford the expense, Halley took the charges upon himself, although his own resources had been recently seriously damaged by the death of his father.

The publication of Newton's Principia, which, but for him, might never have seen the light, and most certainly would have been long delayed, is Halley's highest claim to our gratitude. But, apart from this, his record of scientific achievement is indeed a noble one. Always, from boyhood, he had taken a great interest in the behaviour of the magnetic compass, and he now followed up the study of its variations with the greatest energy. For this purpose it was necessary that he should travel, in view of the great importance of the subject to navigation. King William III. gave him a captain's commission in the Royal Navy—a curious and interesting illustration of the close connection between astronomy and the welfare of our navy—and placed him in command of a 'pink,' that is to say, a small vessel with pointed stern, named the Paramour, in which he proceeded to the southern ocean. His first voyage was unfortunate, but the Paramour was recommissioned in 1699, and he sailed in it as far as south latitude 52°.

In 1701 and the succeeding year he made further voyages in the Paramour, surveying the tides and coasts of the British Channel and of the Adriatic, and helping in the fortification of Trieste. He became Savilian Professor of Geometry at Oxford in 1703, having failed twelve years previously to secure the Savilian Professorship of Astronomy, mainly through the opposition of Flamsteed, who had already formed a strong prejudice against him, which some writers have traced to Halley's detection of several errors in one of Flamsteed's tide-tables, others to Halley's supposed materialistic views. Probably the difference was innate in the two men. There was likely to be but little sympathy between the strong, masterful man of action and society and the secluded, self-conscious, suffering invalid. At any rate, in the contest between Newton and Flamsteed, which has been already described, Halley took warmly the side of the former, and was appointed to edit the publication of Flamsteed's results, and, on the death of the latter, to succeed him at the Royal Observatory.

The condition of things at Greenwich when Halley succeeded to the post of Astronomer Royal in 1720 was most discouraging. The instruments there had all belonged to Flamsteed, and therefore, most naturally, had been removed by his widow. The Observatory had practically to be begun de novo, and Halley had now almost attained the age at which in the present day an Astronomer Royal would have to retire. More fortunate, however, than his predecessor, he was able to get a grant for instruments, and he equipped the Observatory as well as the resources of the time permitted, and his transit instrument and great eight-foot quadrant still hang upon the Observatory walls.

As Astronomer Royal his great work was the systematic observation of the positions of the moon through an entire saros. As is well known, a period of eighteen years and ten or eleven days brings the sun and moon very nearly into the same positions relatively to the earth which they occupied at the commencement of the period. This period was well known to the ancient Chaldeans, who gave it its name, since they had noticed that eclipses of the sun or eclipses of the moon recurred at intervals of the above length. It was Halley's desire to obtain such a set of observations of the moon through an entire saros period as to be able to deduce therefrom an improved set of tables of the moon's motion. It was an ambitious scheme for a man so much over sixty to undertake, nevertheless he carried it through successfully.

His desire to complete this scheme, and to found upon it improved lunar tables, hindered him from publishing his observations, for he feared that others might make use of them before he was in a position to complete his work himself. This omission to publish troubled Newton, who, as President of the Royal Society—the Greenwich Board of Visitors having lapsed at Queen Anne's death—drew attention at a meeting of the Royal Society, March 2, 1727, to Halley's disobedience of the order issued under Queen Anne, for the prompt communication of the Observatory results. That Newton should thus have put public pressure upon Halley, the man to whom he was so much indebted, and with whom there was so close an affection, is sufficient proof that his similar attitude towards Flamsteed was one of principle and not of arbitrariness. Halley, on his side, stood firm, as Flamsteed had done, urging the danger that, by publishing before he had completed his task, he might give an opportunity to others to forestall his results. It is said—probably without sufficient ground—that this refusal broke Newton's heart and caused his death. Certainly Halley's writings in that very year show his reverence and affection for Newton to have been as keen and lively as ever.

Halley's work at the Observatory went on smoothly, on the lines he had laid down for himself, for ten years after Newton's death; but in 1737 he had a stroke of paralysis, and his health, which had been remarkably robust up to that time, began to give way. He died January 14, 1742, and was buried in the cemetery of Lee Church.

As an astronomer, his services to the science rank higher than those of his predecessor; but as Astronomer Royal, as director, that is to say, of Greenwich Observatory, he by no means accomplished as much as Flamsteed had done. Professor Grant, in his History of Physical Astronomy, says that he seems to have undervalued those habits of minute attention which are indispensable to the attainment of a high degree of excellence in the practice of astronomical observation. He was far from being sufficiently careful as to the adjustment of his instruments, the going of his clocks, or the recording of his own observations. The important feature of his administration was that under him the Observatory was first supplied with instruments which belonged to it.

HALLEY'S QUADRANT.
(From an old print.)

His astronomical work apart from the Observatory was of the first importance. He practically inaugurated the study of terrestrial magnetism, and his map giving the results of his observations during his voyage in the Paramour introduced a new and most useful style of recording observations. He joined together by smooth curves places of equal variation, the result being that the chart shows at a glance, not merely the general course of the variation over the earth's surface, but its value at any spot within the limits of the chart.

Another work which has justly made his name immortal was the prediction of the return of the comet which is called by his name, to which reference will be made later. Another great scheme, and one destined to bear much fruit, was the working out of a plan to determine the distance of the sun by observations of the transit of Venus.

Of attractive appearance, pleasing manners, and ready wit, loyal, generous, and free from self-seeking, he probably was one of the most personally engaging men who ever held the office.

The salary of the Astronomer Royal remained under Halley at the same inadequate rate which it had done under Flamsteed—£100, without provision for an assistant. But in 1729 Queen Caroline, learning that Halley had actually had a captain's commission in the Royal Navy, secured for him a post-captain's pay.

JAMES BRADLEY.
(From the painting by Hudson.)

Halley's work is represented at the Observatory by two of his instruments which are still preserved there, and which hang on the west wall of the present transit room: the Iron Quadrant afterwards made famous by the observations of Bradley, and 'Halley's Transit,' the first of the great series of instruments upon which the fame of Greenwich chiefly rests. This transit instrument seems to have been set up in a small room at the west end of what is now known as the North Terrace. His quadrant was mounted on the pier which is now the base of the pier of the astrographic telescope. This pier was the first extension which the Observatory received from the original building.

On the breakdown of his health Halley nominated as his successor, James Bradley; indeed, it is stated that he offered to resign in his favour. He had known him then for over twenty years, and that keen and generous appreciation of merit in others which was characteristic of Halley had led him very early to recognize Bradley's singular ability.

James Bradley was born in 1692 or 1693, of an old North of England family. His birthplace was Sherbourne, in Gloucestershire, and he was educated at North Leach Grammar School and at Baliol College, Oxford. During the years of his undergraduateship he resided much with his uncle, the Rev. James Pound, Rector of Wanstead, Essex, an ardent amateur astronomer, a frequent visitor at the Observatory in Flamsteed's time, and one of the most accurate observers in the country. From him, no doubt, he derived his love of the science, and possibly some of his skill in observation.

Bradley's earliest observations seem to have been devoted to the phenomena of Jupiter's satellites and to the measures of double stars. The accuracy with which he followed up the first drew the attention of Halley, and so began a friendship which lasted through life. His observations of double stars, particularly of Castor, only just failed to show him the orbital movement of the pair, because his attention was drawn to other subjects before it had become sufficiently obvious.

In 1719 Bradley and his uncle made an attempt to determine the distance of the sun through observations of Mars when in opposition, observations which were so accurate that they sufficed to show that the distance of the sun could not be greater than 125 millions of miles, nor less than about 94 millions. The lower limit which they thus found has proved to be almost exactly correct, our best modern determinations giving it as 93 millions. The instrument with which the observations were made was a novel one, being 'moved by a machine that made it to keep pace with the stars;' in other words, it was the first, or nearly the first, example of what we should now call a clock-driven equatorial.

That same year he was offered the Vicarage of Bridstow, near Ross, in Monmouthshire, where, having by that time taken priest's orders, he was duly installed, July, 1720. To this was added the sinecure Rectory of Llandewi-Velgry; but he held both livings only a very short time. In 1721 the death of Dr. John Keill rendered vacant the Savilian Professorship of Astronomy at Oxford, for which Bradley became a candidate, and was duly elected, and resigned his livings in consequence.

It was whilst he was Savilian Professor that Bradley made that great discovery which will always be associated with his name. Though professor at Oxford, he had continued to assist his uncle, Mr. Pound, at his observations at Wanstead, and after the death of the latter he still lived there as much as possible, and continued his astronomical work. But in 1725 he was invited by Mr. Samuel Molyneux, who had set up a twenty-four-foot telescope made by Graham as a zenith tube at his house on Kew Green, to verify some observations which he was making. These were of the star Gamma Draconis, a star which passes through the zenith of London, and which, therefore, had been much observed both by Flamsteed and Hooke, inasmuch as by fixing a telescope in an absolutely vertical position—a position which could be easily verified—it was easy to ascertain if there was any minute change in the apparent position of the star. Dr. Hooke had declared that there was such a change, a change due to the motion of the earth in its orbit, which would prove that the star was not an infinite distance from the earth, the seeming change of its place in the sky corresponding to the change in the place of the earth from which the observer was viewing it.

Bradley found at once that there was such a change—a marked one. It amounted to as much as 1´´ of arc in three days; but it was not in the direction in which the parallax of the star would have moved it, but in the opposite. Whether, therefore, the star was near enough to show any parallax or not, some other cause was giving rise to an apparent displacement of the star, which entirely masked and overcame the effect of parallax.

So far, Bradley had but come to the same point which Flamsteed had reached. Flamsteed had detected precisely the same apparent displacement of stars, and, like Hooke, had ascribed it to parallax. Cassini had shown that this could not be the case, as the displacement was in the wrong direction; and there the matter had rested. Bradley now set to follow the question up. Other stars beside Gamma Draconis were found to show a displacement of the same general character, but the amount varied with their distance from the plane of the ecliptic, the earth's orbit. The first explanation suggested was that the axis of the earth, which moves very nearly parallel to itself as the earth moves round the sun, underwent a slight regular 'wobble' in the course of a year. To check this, a star was observed on the opposite side of the pole from Gamma Draconis; then Bradley investigated as to whether refraction might explain the difficulty, but again without success. He now was most keenly interested in the problem, and he purchased a zenith telescope of his own, made, like that of Molyneux, by Graham, and mounted it in his aunt's house at Wanstead, and observed continuously with it. The solution of the problem came at last to him as he was boating on the Thames. Watching a vane at the top of the mast, he saw with surprise that it shifted its direction every time that the boat was put about. Remarking to the boatmen that it was very odd that the wind should change just at the same moment that there was a shift in the boat's course, they replied that there was no change in the wind at all, and that the apparent change of the vane was simply due to the change of direction of the motion of the boat.

GRAHAM'S ZENITH SECTOR.
(From an old print.)

This supplied Bradley with a key to the solution of the mystery that had troubled him so long. It had been discovered long before this that light does not travel instantaneously from place to place, but takes an appreciable time to pass from one member of the solar system to another. This had been discovered by Römer from observations of the satellites of Jupiter. He had noted that the eclipses of the satellites always fell late of the computed time, when Jupiter was at his greatest distance from the earth; and Bradley's own work in the observation of those satellites had brought the fact most intimately under his own acquaintance. The result of the boating incident taught him, then, that he might look upon light as analogous to the wind blowing on the boat. As the wind, so long as it was steady, would seem to blow from one fixed quarter so long as the boat was also in rest, but as it seemed to shift its direction when the boat was moving and changed its direction, so he saw that the light coming from a particular star must seem to slightly change the direction in which it came, or, in other words, the apparent position of the star, to correspond with the movement of the earth in its orbit round the sun.

This was the celebrated discovery of the Aberration of Light, a triumph of exact observation and of clear insight. As to the exactness of Bradley's observations, it is sufficient to say that his determination of the value of the 'Constant of Aberration' gave it as 20·39´´; the value adopted to-day is 20·47´´.

On the death of Halley, in 1742, Bradley was appointed to succeed him. He found the Observatory in as utterly disheartening a condition as his predecessors had done. As already mentioned, Halley had not the same qualifications as an observer that Flamsteed had. He was, further, an old man when appointed to the post, he had no assistant provided for him, and the last five years of his life his health and strength had entirely given way. Under these circumstances, it was no wonder that Bradley found the instruments of the Observatory in a deplorable state. Nevertheless, he set to work most energetically, and in the year of his appointment he made 1500 observations in the last five months of the year. He was particularly earnest in examining the condition and the errors of his instruments; and as their defects became known to him, he was more and more anxious for a better equipment. He moved the Royal Society, therefore, to apply on his behalf for the instruments he required; and a petition from that body, in 1748, obtained what in those days must be considered the generous grant of £1000, the proceeds of the sale of old Admiralty stores. The principal instruments purchased therewith were a mural quadrant and a transit instrument, both eight feet in focal length, still preserved on the walls of the transit-room. It is interesting also to note that, following in the steps of Halley, and forecasting, as it were, the magnetic observatory which Airy would found, he devoted £20 of the grant to purchasing magnetic instruments.

Meantime he had continued his observations on aberration, and had discovered that the aberration theory was not sufficient entirely to account for the apparent changes in places of stars which he had discovered. A second cause was at work, a movement of the earth's axis, a 'wobble' in its inclination, technically known as Nutation, which is due to the action of the moon, and goes through its course in a period of nineteen years.

Beside these two great discoveries of aberration and nutation, Bradley's reputation rests upon his magnificent observations of the places of more than three thousand stars. This part of his work was done with such thoroughness, that the star-places deduced from them form the basis of most of our knowledge as to the actual movements of individual stars. In particular, he was careful to investigate and to correct for the errors of his instrument, and to determine the laws of refraction, introducing corrections for changes in the readings of thermometer and barometer. His tables of refraction were used, indeed, for seventy years after his death. Of his other labours it may be sufficient to refer to his determination of the longitudes of Lisbon and of New York, and to his effort to ascertain the parallax of the sun and moon, in combination with La Caille, who was observing at the Cape of Good Hope.

As Astronomer Royal, Bradley's great achievement was the high standard to which he raised the practical work of observation. From his day onwards, also, there was always at least one assistant. His first assistant was his own nephew, John Bradley, who received the munificent salary of ten shillings a week. Still, this was not out of proportion to the then salary of the Astronomer Royal, which practically amounted only to £90. However, in 1752, Bradley was awarded a Crown pension of £250 a year. He refused the living of Greenwich, which was offered him in order to increase his emoluments, on the ground that he could not suitably fulfil the double office. Bradley's later assistants were Charles Mason and Charles Green.

Bradley's last work was the preparation for the observations of the transit of Venus of 1761, according to the lines laid down by his predecessor, Halley. His health gave way, and he became subject to melancholia, so that the actual observations were taken by the Rev. Nathaniel Bliss, who succeeded him in his office after his death, in 1762. He was buried at Minchinhampton.

So far as we know Bradley's character, he seems to have been a gentle, modest, unassuming man, entirely free from self-seeking, and indifferent to personal gain. He was in many ways an ideal astronomer, exact, methodical, and conscientious to the last degree. His skill as an observer was his chief characteristic; and though his abilities were not equal as a mathematician or a mechanician, yet, on the one hand, he had a very clear insight into the meaning of his observations, and, on the other, he was skilful enough to himself adjust, repair, and improve his instruments.

Of Bradley's instruments, there are still preserved his famous twelve-and-a-half-foot zenith sector, with which he made his two great discoveries; his brass quadrant, which in 1750 he substituted for Halley's iron quadrant; his transit instrument, and equatorial sector. Bradley added to the buildings of the Observatory that portion which is now represented by the upper and lower computing rooms, and the chronometer room, which adjoins the latter. This room—the chronometer room—was his transit room, and the position of the shutters is still marked by the window in the roof.

The Rev. Nathaniel Bliss, who succeeded Bradley, only held the office for a couple of years, and during that time was much at Oxford. He, therefore, has left no special mark behind him as Astronomer Royal.

He was born November 28, 1700. His father, like himself, Nathaniel Bliss, was a gentleman, of Bisley, Gloucestershire.

NATHANIEL BLISS.
(From an engraving on an old pewter flagon.)

Bliss graduated at Pembroke College, Oxford, as B.A. in 1720, and M.A. in 1723. He became the Rector of St. Ebb's, Oxford, in 1736, and on Halley's death succeeded him as Savilian Professor of Geometry. He supplied Bradley with his observations of Jupiter's satellites, and from time to time, at his request, rendered him some assistance at the Royal Observatory. This was particularly the case, as has been already mentioned, with respect to the transit of Venus of 1761, the observations of which were carried out by Bliss, owing to Bradley's ill-health. It was natural, therefore, that on Bradley's death he should succeed to the vacant post; but he held it too short a time to do any distinctive work. Such observations as he made seem to have been entirely in continuation of Bradley's. He took a great interest, however, in the improvement of clocks, a department in which so much was being done at this time by Graham, Ellicott, and others.

Nevil Maskelyne, the fifth Astronomer Royal, was, like Bliss, a close friend of Bradley's. He was the third son of a wealthy country gentleman, Edmund Maskelyne, of Purton, in Wiltshire. Maskelyne was born in London, October 6, 1732, and was educated at Westminster School. Thence he proceeded to Cambridge, where he graduated seventh Wrangler in 1754. He was ordained to the curacy of Barnet in 1755, and, twenty years later, was presented by his nephew, Lord Clive, to the living of Shrawardine, in Shropshire. In 1782 he was presented by his college to the Rectory of North Runcton, Norfolk.

The event which turned his thoughts in the direction of astronomy was the solar eclipse of July 25, 1748; and about the time that he was appointed to the curacy of Barnet he became acquainted with Bradley, then the Astronomer Royal, to whom he gave great assistance in the preparation of his table of refractions.

Like Halley before him, he made an astronomical expedition to the island of St. Helena. This was for the special purpose of observing the transit of Venus of June 6, 1761, Bradley having induced the Royal Society to send him out for that purpose. Here he stayed ten months, and made many observations. But though the transit of Venus was his special object, it was not the chief result of the expedition: not because clouds hindered his observations, but because the voyage gave him the especial bent of his life.

Halley had actually held a captain's commission in the Royal Navy, and commanded a ship; Maskelyne, more than any of the Astronomers Royal before or since, made the improvement of the practical business of navigation his chief aim. None of all the incumbents of the office kept its original charter—'To find the so much desired Longitude at Sea, for the perfecting the Art of Navigation,' so closely before him.

The solution of the problem was at hand at this time—its solution in two different ways. On the one hand, the offer by the Government of a reward of £20,000 for a clock or watch which should go so perfectly at sea, notwithstanding the tossing of the ship and the wide changes of temperature to which it might be exposed, that the navigator might at any moment learn the true Greenwich time from it, had brought out the invention of Harrison's time-keeper; on the other hand, the great improvement that had now taken place in the computation of tables of the moon's motion, and the more accurate star-catalogues now procurable, had made the method of 'lunars,' suggested a hundred and thirty years before by the Frenchman, Morin, and others, a practicable one.

NEVIL MASKELYNE.

In principle, the method of finding the longitude from 'lunars,' that is to say, from measurements of the distances between the moon and certain stars, is an exceedingly simple one. In actual practice, it involves a very toilsome calculation, beside exact and careful observation. The principle, as already mentioned, is simply this: The moon travels round the sky, making a complete circuit of the heavens in between twenty-seven and twenty-eight days. It thus moves amongst the stars, roughly speaking, its own diameter, in about an hour. When once its movements were sufficiently well known to be exactly predicted, almanacs could be drawn up in which the Greenwich time of its reaching any definite point of the sky could be predicted long beforehand; or, what comes to the same thing, its distances from a number of suitable stars could be given for definite intervals of Greenwich time. It is only necessary, then, to measure the distances between the moon and some of these stars, and by comparing them with the distances given in the almanac, the exact time at Greenwich can be inferred. As has been already pointed out, the determination of the latitude of the ship and of the local time at any place where the ship is, is not by any means so difficult a matter; but the local time being known and the Greenwich time, the difference between these gives the longitude; and the latitude having been also ascertained, the exact position of the ship is known.

There are, of course, difficulties in the way of working out this method. One is, that whilst it takes the sun but twenty-four hours to move round the sky from one noon to the next, and consequently its movements, from which the local time is inferred, are fairly rapid, the moon takes nearly twenty-eight days to move amongst the stars from the neighbourhood of one particular star round to that particular star again. Consequently, it is much easier to determine the local time with a given degree of exactness than the Greenwich time; it is something like the difference of reading a clock from both hands and from the hour hand alone.

There are other difficulties in the case which make the computation a long and laborious one, and difficult in that sense; but they do not otherwise affect its practicability.

During this voyage to St. Helena, both when outward bound and when returning, Maskelyne gave the method of 'lunars' a very thorough testing, and convinced himself that it was capable of giving the information required. For by this time the improvement of the sextant, or quadrant as it then was, by the introduction of a second mirror, by Hadley, had rendered the actual observation at sea of lunar distances, and of altitudes generally, a much more exact operation.

This conclusion he put at once to practical effect, and, in 1763, he published the British Mariner's Guide, a handbook for the determination of the longitude at sea by the method of lunars.

At the same time, the other method, that by the time-keeper or chronometer, was practically tested by him. The time-keeper constructed by John Harrison had been tested by a voyage to Jamaica in 1761, and now, in 1763, another time-keeper was tested in a voyage to Barbadoes. Charles Green, the assistant at Greenwich Observatory, was sent in charge of the chronometer, and Maskelyne went with him to test its performance, in the capacity of chaplain to his Majesty's ship Louisa.

HADLEY'S QUADRANT.
(From an old print.)

The position which Maskelyne had already won for himself as a practical astronomer, and the intimate relations into which he had entered with Bradley and Bliss, made his appointment to the Astronomer Royalship, on the death of the latter, most suitable. At once he bent his mind to the completion of the revolution in nautical astronomy which his British Mariner's Guide had inaugurated, and in the year after his appointment he published the first number of the Nautical Almanac, together with a volume entitled, Tables Requisite to be Used with the Nautical Ephemeris, the value of which was so instantly appreciated, that 10,000 copies were sold at once.

The Nautical Almanac was Maskelyne's greatest work, and it must be remembered that he carried it on from this time up to the day of his death—truly a formidable addition to the routine labours of an Astronomer Royal who had but a single assistant on his staff. The Nautical Almanac was, however, in the main not computed at the Observatory; the calculations were effected by computers living in different parts of the country, the work being done in duplicate, on the principle which Flamsteed had inaugurated in the preparation of his Historia Cœlestis.

Maskelyne's next service to science was almost as important. He arranged that the regular and systematic publication of the observations made at Greenwich should be a distinct part of the duties of an Astronomer Royal, and he procured an arrangement by which a special fund was set apart by the Royal Society for printing them. His observations covering the years 1776 to 1811 fill four large folio volumes, and though, as already stated, he had but one assistant, they are 90,000 in number. Thus it was Maskelyne who first rendered effective the design which Charles II. had in the establishment of the Observatory. Flamsteed and Halley had been too jealous of their own observations to publish; Bradley's observations—though he himself was entirely free from this jealousy—were made, after his death, the subject of litigation by his heirs and representatives, who claimed an absolute property in them, a claim which the Government finally allowed. None of the three, however much their work ultimately tended to the improvement of the art of navigation, made that their first object. Whereas Maskelyne set this most eminently practical object in the forefront, and so gave to the Royal Observatory, which under his predecessors somewhat resembled a private observatory, its distinctive characteristics of a public institution.

It fell to Maskelyne to have to advise the Government as to the assignment of their great reward of £20,000 for the discovery of the longitude at sea. Maskelyne, while reporting favourably of the behaviour of Harrison's time-keeper, considered that the method of 'lunars' was far too important to be ignored, and he therefore recommended that half the sum should be given to Harrison for his watch, whilst the other half was awarded for the lunar tables which Mayer, before his death, had sent to the Board of Longitude. This decision, though there can be no doubt it was the right one, led to much dissatisfaction on the part of Harrison, who urged his claim for the whole grant very vigorously; and eventually the whole £20,000 was paid him. The whole question of rewards to chronometer-makers must have been one which caused Maskelyne much vexation. He was made the subject of a bitter and most voluminous attack by Thomas Mudge, for having preferred the work of Arnold and Earnshaw to his own.

Otherwise his reign at the Observatory seems to have been a singularly peaceful one, and there is little to record about it beyond the patient prosecution, year by year, of an immense amount of sober, practical work. To Maskelyne, however, we owe the practice of taking a transit of a star over five wires instead of over one, and he provided the transit instrument with a sliding eye-piece, to get over the difficulty of the displacement which might ensue if the star were observed askew when out of the centre of the field. To Maskelyne, too, we owe in a pre-eminent degree the orderly form of recording, reducing, and printing the observations. Much of the work in this direction which is generally ascribed to Airy was really due to Maskelyne. Indeed, without a wonderful gift of organization, it would have been impossible to plan and to carry the Nautical Almanac.

Beside the editing of various works intended for use in nautical astronomy or in general computation, the chief events of his long reign at Greenwich were the transit of Venus in 1769, which he himself observed, and for which he issued instructions in the Nautical Almanac; and his expedition in 1774 to Scotland, where he measured the deviation of the plumb-line from the vertical caused by the attraction of the mountain Schiehallion, deducing therefrom the mean density of the earth to be four and a half times that of water.

JOHN POND.
(From an old engraving.)

He died at the Observatory, February 9, 1811, aged 79, leaving but one child, a daughter, who married Mr. Anthony Mervin Story, to whom she brought the family estates in Wiltshire, inherited by Maskelyne on the deaths of his elder brothers, and, in consequence, Mr. Story added the name of Maskelyne to his own.

Maskelyne's character and policy as Astronomer Royal have been sufficiently dwelt upon. His private character was mild, amiable, and generous. 'Every astronomer, every man of learning, found in him a brother;' and, in particular, when the French Revolution drove some French astronomers to this country to find a refuge, they received from the Astronomer Royal the kindest reception and most delicate assistance.

Maskelyne added no instrument to the Observatory during his reign, though he improved Bradley's transit materially. He designed the mural circle, but it was not completed until after his death. His additions to the Observatory buildings consisted of three new rooms in the Astronomer Royal's house, and the present transit circle room.

John Pond was recommended by Maskelyne as his successor at Greenwich. At the time of his succession he was forty-four years of age, having been born in 1767. He was educated at Trinity College, Cambridge, and then spent some considerable time travelling in the south of Europe and Egypt. On his return home he settled at Westbury, where he erected an altazimuth by Troughton, with a two-and-a-half-foot circle. A born observer, his observations of the declinations of some of the principal fixed stars showed that the instrument which Maskelyne was using at Greenwich—the quadrant by Bird—could no longer be trusted. Maskelyne, in consequence, ordered a six-foot mural circle from Troughton, but did not live to see it installed, and in 1816 this was supplemented by Troughton's transit instrument of five inches aperture and ten feet focal length.

The introduction of these two important instruments, and of other new instruments, together with new methods of observation, form one of the chief characteristics of Pond's administration. Under this head must be specially mentioned the introduction of the mercury trough, both for determining the position of the vertical, and for obtaining a check upon the flexure of the mural circle in different positions; and the use in combination of a pair of mural circles for determining the declinations of stars.

Another characteristic of his reign was that under him there was the first attempt to give the Astronomer Royal a salary somewhat higher than that of a mechanic, and to support him with an adequate staff of assistants. His salary was fixed at £600 a year, and the single assistant of Maskelyne was increased to six.

This multiplication of assistants was for the purpose of multiplying observations, for Pond was the first astronomer to recognize the importance of greatly increasing the number of all observations upon which the fundamental data of astronomy were to be based.

In 1833 he finished his standard catalogue of 1113 stars, at that time the fullest of any catalogue prepared on the same scale of accuracy. 'It is not too much to say,' was the verdict of the Royal Astronomical Society, 'that meridian sidereal observation owes more to him than to all his countrymen put together since the time of Bradley.'

A yet higher testimony to the exactness of his work is given by his successor, Airy.

'The points upon which, in my opinion, Mr. Pond's claims to the gratitude of astronomers are founded, are principally the following. First and chief, the accuracy which he introduced into all the principal observations. This is a thing which, from its nature, it is extremely difficult to estimate now, so long after the change has been made; and I can only say that, so far as I can ascertain from books, the change is one of very great extent; for certainty and accuracy, astronomy is quite a different thing from what it was, and this is mainly due to Mr. Pond.'

The same authority eulogizes him further for his laborious working out of every conceivable cause or indication of error in his declination instruments, for the system which he introduced in the observation of transits, for the thoroughness with which he determined all his fundamental data, and for the regularity which he infused into the Greenwich observations.

One result of this great increase of accuracy was that Pond was able at once authoritatively to discard the erroneous stellar parallaxes that had been announced by Brinkley, Royal Astronomer for Ireland.

But Pond's administration was open, in several particulars, to serious censure, and the Board of Visitors, which had been for many years but a committee of the Royal Society, but which had recently been reconstituted, proved its value and efficiency by the remonstrances which it addressed to him, and which eventually brought about his resignation. His personal skill and insight as an observer were of the highest order; but either from lack of interest or failing health, he absented himself almost entirely from the Observatory in later years, visiting it only every ninth or tenth day. He had caused the staff of assistants to be increased from one to six, but had stipulated that the men supplied to him should be 'drudges.' His minute on the subject ran—

'I want indefatigable, hard-working, and, above all, obedient drudges (for so I must call them, although they are drudges of a superior order), men who will be contented to pass half their day in using their hands and eyes in the mechanical act of observing, and the remainder of it in the dull process of calculation.'

This was a fatal mistake, and one which it is very hard to understand how any one with a real interest in the science could have made. Men who had the spirit of 'drudges,' to whom observation was a mere 'mechanical act,' and calculation a 'dull process,' were not likely to maintain the honour of the Observatory, particularly under an absentee Astronomer Royal. Pond tried to overcome the difficulty by devising rules for their guidance of iron rigidity. The result was that after his resignation, in 1835, the First Lord and the Secretary of the Admiralty expressed their feeling to Airy, Pond's successor, 'that the Observatory had fallen into such a state of disrepute that the whole establishment should be cleared out.' A further evil was the excessive development of chronometer business, so as practically to swamp the real work of the Observatory, whilst the prices paid for the chronometers at this time were often much larger than would have been the case under a more business-like administration.

With all his merits, therefore, as an observer, the administration of Pond was, in some respects, the least satisfactory of all that the Observatory has known, and he alone of all the Astronomers Royal retired under pressure. He did not long survive his resignation, dying in September, 1836. He was buried by the side of Halley, in the churchyard at Lee.

Of Pond's instruments, the Observatory retains the fine transit instrument which was constructed by Troughton at his direction, and the mural circle, designed by Maskelyne, but which Pond was the first to use. Both of these have, of course, long been obsolete, and now hang on the walls of the transit room. The small equatorial, called, after its donor, the Shuckburgh equatorial, was also added in Pond's day, and though practically never used, still remains mounted in its special dome.

CHAPTER IV

AIRY

One hundred and sixty years from the day when Flamsteed laid the foundation stone of the Observatory, the Royal Warrant under the sign manual was issued, appointing the seventh and strongest of the Astronomers Royal, August 11, 1835. He actually entered on his office in the following October, but did not remove to the Observatory until the end of the year.

George Biddell Airy was born at Alnwick, in Northumberland, on July 27, 1801. His father was William Airy, of Luddington, in Lincolnshire, a collector of excise; his mother was the daughter of George Biddell, a well-to-do farmer, of Playford, near Ipswich. He was educated at the Grammar School, Colchester, and so distinguished himself there that although his father was at this time very straitened in his circumstances, it was resolved that young Airy should go to Cambridge. Here he was entered as sizar at Trinity College, and his robust, self-reliant character was seen in the promptness with which he rendered himself independent of all pecuniary help from his relatives. In 1823 he graduated as Bachelor of Arts, being Senior Wrangler and Smith's prizeman, entirely distancing all other men of his year. He had already begun to pay attention to astronomy, at first from the side of optics, to the study of which he had been very early attracted; a paper of his on the achromatism of eye-pieces and microscopes, written in 1824, being one of especial value. In 1826 he attempted to determine 'the diminution of gravity in a deep mine'—that of Dolcoath, in Cornwall. In the winter of 1823-24 he was invited to London by Mr. (afterwards Sir) James South, who took him, amongst other places, to Greenwich Observatory, and gave him his first introduction to practical astronomy. In 1826 he was appointed Lucasian Professor at Cambridge, and in 1828, Plumian Professor, with the charge of the new University Observatory. Prior to his election he had definitely told the electors that the salary proposed was not sufficient for him to undertake the responsibility of the Observatory. He followed this up by a formal application for an increase, which created not a little commotion at the time, the action being so unprecedented; and after a delay of a little over a year he obtained what he had asked for. The delay gave rise, however, to the remark of a local wit, that the University had given 'to Airy, nothing, a local habitation and a name.'

GEORGE BIDDELL AIRY.

The seven years which he spent in the Cambridge Observatory were the best possible preparation for that greater charge which he was to assume later. When he entered on his duties the Observatory had been completed four years, but no observations had been published; there was no assistant, and the only instruments were a couple of good clocks and a transit instrument. But Airy set to work at once with so much energy that the observations for 1828 were published early in the following year, and he had very quickly worked out the best methods for correcting and reducing his observations. In 1829 an assistant was granted to him, in 1833 a second, and in the latter year Mr. Baldrey, the senior assistant, observed about 5000 transits, and Mr. Glaisher, the junior, about the same number of zenith distances.

A syndicate had been appointed at Cambridge for the purpose of visiting the Observatory once in each term, and making an annual report to the senate. A smaller-minded and less acute man than Airy might have resented such an arrangement. He, on the contrary, threw himself heartily into it, and made such formal written reports to the syndicate as best helped them in the performance of their duty, and at the same time secured for the Observatory the support and assistance which from time to time it required. On his appointment to Greenwich, he at once entered into the same relations to the Board of Visitors of that Observatory, and from that time forth the friction that had occasionally existed between the Board and the Astronomer Royal in the past entirely ceased. The Board was henceforth no longer a body whose chief function was to reprove, to check, or to quicken the Astronomer Royal, but rather a company of experts, before whom he might lay the necessities of the Observatory, that they in turn might present them to the Government.

Such representations were not likely to be in vain. For, as Mr. Sheepshanks has left on record—

'When Mr. Airy wants to carry anything into effect by Government assistance, he states, clearly and briefly, why he wants it; what advantages he expects from it; and what is the probable expense. He also engages to direct and superintend the execution, making himself personally responsible, and giving his labour gratis. When he has obtained permission (which is very seldom refused), he arranges everything with extraordinary promptitude and foresight, conquers his difficulties by storm, and presents his results and his accounts in perfect order, before men like ... or myself would have made up our minds about the preliminaries. Now, men in office naturally like persons of this stamp. There is no trouble, no responsibility, no delay, no inquiries in the House; the matter is done, paid for, and published, before the seekers of a grievance can find an opportunity to be heard. This mode of proceeding is better relished by busy statesmen than recommendations from influential noblemen or fashionable ladies.'

His first action towards the Board was, however, a very bold and independent one. He made strong representations on the subject of the growth of the chronometer business, which proved displeasing to the Hydrographer, Captain Beaufort, who was one of the official visitors, and by his influence the report was not printed. Airy 'kept it, and succeeding reports, safe for three years, and then the Board of Visitors agreed to print them, and four reports were printed together, and bound with the Greenwich Observations of 1838.'

With the completion of arrangements which put the chronometer business in proper subordination to the scientific charge of the Observatory, Airy was free to push forward its development on the lines which he had already marked out for himself. To go through these in detail is simply to describe the Observatory as he left it. Little by little he entirely renovated the equipment. Greatly as Pond had improved the instruments of the Observatory, Airy carried that work much further still. Though he did not observe much himself, and was not Pond's equal in the actual handling of a telescope, he had a great mechanical gift, and the detail in its minutest degree of every telescope set up during his long reign was his own design.

In the work of reduction he introduced the use of printed skeleton forms, to which Pond had been a stranger. The publication of the Greenwich results was carried on with the utmost regularity; and, in striking contrast to the reluctance of Flamsteed and Halley, he was always most prompt in communicating any observations to every applicant who could show cause for his request for them.

It is most difficult to give any adequate impression of his far-reaching ability and measureless activity. Perhaps the best idea of these qualities may be obtained from a study of his autobiography, edited and published some four years after his death by his son. The book, to any one who was not personally acquainted with Airy, is heavy and monotonous, chiefly for the reason that its 400 pages are little but a mere catalogue of the works which he undertook and carried through; and catalogues, except to the specialist, are the dullest of reading. To enter into the details of his work might fill a library.

THE ASTRONOMER ROYAL'S ROOM.